p525™/d3 draft guide for the design and installation of

P525D3 April 2015 Draft Guide for the Design and Installation of Cable Systems in Substations

Copyright copy 2015 IEEE All rights reserved This is an unapproved IEEE Standards Draft subject to change

P525tradeD3 1

Draft Guide for the Design and 2

Installation of Cable Systems in 3

Substations 4

Sponsor 5 6 Substations Committee 7 of the 8 IEEE Power and Energy Society 9 10 11 Approved ltDate Approvedgt 12 13 IEEE-SA Standards Board 14 15 Copyright copy 2015 by the Institute of Electrical and Electronics Engineers Inc 16 Three Park Avenue 17 New York New York 10016-5997 USA 18

All rights reserved 19

This document is an unapproved draft of a proposed IEEE Standard As such this document is subject to 20 change USE AT YOUR OWN RISK Because this is an unapproved draft this document must not be 21 utilized for any conformancecompliance purposes Permission is hereby granted for IEEE Standards 22 Committee participants to reproduce this document for purposes of standardization consideration Prior to 23 adoption of this document in whole or in part by another standards development organization permission 24 must first be obtained from the IEEE Standards Activities Department (stdsiprieeeorg) Other entities 25 seeking permission to reproduce this document in whole or in part must also obtain permission from the 26 IEEE Standards Activities Department 27

IEEE Standards Activities Department 28 445 Hoes Lane 29 Piscataway NJ 08854 USA 30

31



Abstract The design installation and protection of wire and cable systems in substations are 1 covered in this guide with the objective of minimizing cable failures and their consequences 2 Keywords acceptance testing cable cable installation cable selection communication cable 3 electrical segregation fiber-optic cable handling power cable pulling tension raceway 4 recommended maintenance routing separation of redundant cable service conditions 5 substation transient protection 6



Notice and Disclaimer of Liability Concerning the Use of IEEE Documents IEEE Standards documents are developed 1 within the IEEE Societies and the Standards Coordinating Committees of the IEEE Standards Association (IEEE-SA) 2 Standards Board IEEE develops its standards through a consensus development process approved by the American National 3 Standards Institute which brings together volunteers representing varied viewpoints and interests to achieve the final product 4 Volunteers are not necessarily members of the Institute and serve without compensation While IEEE administers the process 5 and establishes rules to promote fairness in the consensus development process IEEE does not independently evaluate test or 6 verify the accuracy of any of the information or the soundness of any judgments contained in its standards 7

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Comments on Standards Comments for revision of IEEE Standards documents are welcome from any interested party 34 regardless of membership affiliation with IEEE However IEEE does not provide consulting information or advice pertaining 35 to IEEE Standards documents Suggestions for changes in documents should be in the form of a proposed change of text 36 together with appropriate supporting comments Since IEEE standards represent a consensus of concerned interests it is 37 important to ensure that any responses to comments and questions also receive the concurrence of a balance of interests For 38 this reason IEEE and the members of its societies and Standards Coordinating Committees are not able to provide an instant 39 response to comments or questions except in those cases where the matter has previously been addressed Any person who 40 would like to participate in evaluating comments or revisions to an IEEE standard is welcome to join the relevant IEEE 41 working group at httpstandardsieeeorgdevelopwg 42

Comments on standards should be submitted to the following address 43

Secretary IEEE-SA Standards Board 44 445 Hoes Lane 45 Piscataway NJ 08854 46 USA 47

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Copyright copy 2015 IEEE All rights reserved

This is an unapproved IEEE Standards Draft subject to change

iv

Notice to users 1

Laws and regulations 2

Users of IEEE Standards documents should consult all applicable laws and regulations Compliance with 3 the provisions of any IEEE Standards document does not imply compliance to any applicable regulatory 4 requirements Implementers of the standard are responsible for observing or referring to the applicable 5 regulatory requirements IEEE does not by the publication of its standards intend to urge action that is not 6 in compliance with applicable laws and these documents may not be construed as doing so 7

Copyrights 8

This document is copyrighted by the IEEE It is made available for a wide variety of both public and 9 private uses These include both use by reference in laws and regulations and use in private self-10 regulation standardization and the promotion of engineering practices and methods By making this 11 document available for use and adoption by public authorities and private users the IEEE does not waive 12 any rights in copyright to this document 13

Updating of IEEE documents 14

Users of IEEE Standards documents should be aware that these documents may be superseded at any time 15 by the issuance of new editions or may be amended from time to time through the issuance of amendments 16 corrigenda or errata An official IEEE document at any point in time consists of the current edition of the 17 document together with any amendments corrigenda or errata then in effect In order to determine whether 18 a given document is the current edition and whether it has been amended through the issuance of 19 amendments corrigenda or errata visit the IEEE-SA Website at httpstandardsieeeorgindexhtml or 20 contact the IEEE at the address listed previously For more information about the IEEE Standards 21 Association or the IEEE standards development process visit IEEE-SA Website at 22 httpstandardsieeeorgindexhtml 23

Errata 24

Errata if any for this and all other standards can be accessed at the following URL 25 httpstandardsieeeorgfindstdserrataindexhtml Users are encouraged to check this URL for errata 26 periodically 27

Patents 28

Attention is called to the possibility that implementation of this standard may require use of subject matter 29 covered by patent rights By publication of this standard no position is taken by the IEEE with respect to 30 the existence or validity of any patent rights in connection therewith If a patent holder or patent applicant 31 has filed a statement of assurance via an Accepted Letter of Assurance then the statement is listed on the 32 IEEE-SA Website at httpstandardsieeeorgaboutsasbpatcompatentshtml Letters of Assurance may 33 indicate whether the Submitter is willing or unwilling to grant licenses under patent rights without 34 compensation or under reasonable rates with reasonable terms and conditions that are demonstrably free of 35 any unfair discrimination to applicants desiring to obtain such licenses 36




v

Essential Patent Claims may exist for which a Letter of Assurance has not been received The IEEE is not 1 responsible for identifying Essential Patent Claims for which a license may be required for conducting 2 inquiries into the legal validity or scope of Patents Claims or determining whether any licensing terms or 3 conditions provided in connection with submission of a Letter of Assurance if any or in any licensing 4 agreements are reasonable or non-discriminatory Users of this standard are expressly advised that 5 determination of the validity of any patent rights and the risk of infringement of such rights is entirely 6 their own responsibility Further information may be obtained from the IEEE Standards Association 7




vi

Participants 1

At the time this draft guide was completed the D2 Working Group had the following membership 2

Debra Longtin Chair 3 Steve Shelton Vice Chair 4 Brian Farmer Secretary 5

Adam Zook Technical Editor 6

7 Hanna Abdallah 8 Radoslav Barac 9 Kevin Buhle 10 Michael Chavis 11 Randy Clelland 12 Walter Constantine 13 Alan Gaetz 14 Joseph Gravelle 15

Charles Haahr 16 Zachary Hoffmann 17 Benjamin Hooley 18 William Lively 19 Donnie Moreau 20 Michael Nadeau 21 Kimberly Nuckles 22 Pathik Patel 23

Shashi Patel 24 Shashikant Patel 25 Craig Preuss 26 Hamid Sharifnia 27 Kenneth Strahl 28 William Thompson 29 Diane Watkins 30

31

The following members of the ltindividualentitygt balloting committee voted on this guide Balloters may 32 have voted for approval disapproval or abstention 33

[To be supplied by IEEE] 34

Balloter1 35 Balloter2 36 Balloter3 37



44

When the IEEE-SA Standards Board approved this guide on ltDate Approvedgt it had the following 45 membership 46


ltNamegt Chair 48 ltNamegt Vice Chair 49 ltNamegt Past Chair 50 ltNamegt Secretary 51

SBMember1 52 SBMember2 53 SBMember3 54



Member Emeritus 61 62

Also included are the following nonvoting IEEE-SA Standards Board liaisons 63

ltNamegt DOE Representative 64 ltNamegt NIST Representative 65

66 ltNamegt 67

IEEE Standards Program Manager Document Development 68 69

ltNamegt 70




vii

IEEE Standards Program Manager Technical Program Development 1

2




viii

Introduction 1

This introduction is not part of P525D3 Draft Guide for the Design and Installation of Cable Systems in Substations 2

This revision of the guide makes the following changes 3

a) Annex P was added to describe a large station example 4

b) The communications cable information was expanded throughout the document 5

c) Miscellaneous updates were made throughout the document 6

7




ix

Contents 1

1 Overview 1 2 11 Scope 1 3 12 Purpose 2 4

2 Normative references 2 5

3 Definitions acronyms and abbreviations 2 6

4 Control and instrumentation cable 3 7 41 General 3 8 42 Service conditions (see Annex B) 4 9 43 Cable selection (see Annex C) 4 10 44 Cable raceway design (see Annex E) 8 11 45 Routing (see Annex F) 8 12 46 Transient protection (see Annex G) 8 13 47 Electrical segregation (see Annex H) 9 14 48 Separation of redundant cable (see Annex I) 9 15 49 Cable pulling tension (see Annex J) 9 16 410 Handling (see Annex K) 9 17 411 Installation (see Annex L) 9 18 412 Acceptance testing (see Annex M) 9 19 413 Recommended maintenance (see Annex N) 9 20

5 Metallic Communication cables 9 21 51 General 10 22 52 Service conditions 21 23 53 Metallic cable selection 22 24 54 Cable system design 23 25 55 Transient protection 25 26 56 Cable pulling tension (see Annex J) 27 27 57 Handling 28 28 58 Installation (see Annex L) 28 29 59 Acceptance testing 29 30 510 Recommended maintenance (see Annex N) 30 31

6 Fiber-optic cable 30 32 61 General 31 33 62 Fiber types 32 34 63 Service conditions 42 35 64 Cable selection 43 36 65 Cable system design 45 37 66 Transient protection 49 38 67 Cable pulling tension (see Annex J) 50 39 68 Handling (see Annex K) 51 40 69 Installation (see Annex L) 51 41 610 Acceptance testing (see Annex M) 52 42 611 Recommended maintenance (see Annex N) 53 43

7 Low-voltage power cable (ac and dc lt= 1 kV) 53 44 71 General 53 45 72 Service conditions (see Annex B) 53 46




x

73 Cable selection (see Annex C) 54 1 74 Cable raceway design (see Annex E) 54 2 75 Routing (see Annex F) 54 3 76 Transient protection (see Annex G) 54 4 77 Electrical segregation (see Annex H) 54 5 78 Separation of redundant cable (see Annex I) 55 6 79 Cable pulling tension (see Annex J) 55 7 710 Handling (see Annex K) 55 8 711 Installation (see Annex L) 55 9 712 Acceptance testing (see Annex M) 55 10 713 Recommended maintenance (see Annex N) 55 11

8 Medium voltage power cable (1 kV to 35 kV) 55 12 81 Service conditions (see Annex B) 56 13 82 Cable selection (see Annex C) 56 14 83 Cable raceway design (see Annex E) 57 15 84 Routing (see Annex F) 57 16 85 Transient protection (see Annex G) 57 17 86 Electrical segregation (see Annex H) 57 18 87 Separation of redundant cable (see Annex I) 57 19 88 Cable pulling tension (see Annex J) 57 20 89 Handling (see Annex K) 58 21 810 Installation (see Annex L) 58 22 811 Acceptance testing (see Annex M) 58 23 812 Recommended maintenance (see Annex N) 58 24

Annex A (informative) Flowchart 59 25

Annex B (normative) Service conditions for cables 61 26

Annex C (normative) Control and power cable selection 70 27 C1 Conductor 70 28 C2 Ampacity 72 29 C3 Voltage drop 73 30 C4 Short-circuit capability 81 31 C5 Insulation 82 32 C6 Jacket 83 33 C7 Attenuation 84 34 C8 Cable capacitance 84 35

Annex D (informative) Design checklist for metallic communication cables entering a substation 85 36 D1 Pre-design 85 37 D2 Communications requirements 85 38 D3 Cable protection requirements 86 39 D4 Site conditions 86 40 D5 Interface with telephone companyservice provider 86 41 D6 Cost considerations 87 42 D7 Communications system design 87 43

Annex E (normative) Cable raceway design 88 44 E1 Raceway fill and determining raceway sizes 88 45 E2 Conduit 89 46 E3 Cable tray 92 47 E4 Cable tray installation 95 48 E5 Wireways 96 49 E6 Direct burial tunnels and trenches 96 50




xi

Annex F (normative) Routing 99 1 F1 Length 99 2 F2 Turns 99 3 F3 Physical location and grouping 99 4 F4 Fire impact 100 5

Annex G (normative) Transient protection of instrumentation control and power cable 101 6 G1 Origin of transients in substations101 7 G2 Protection measuresmdashGeneral considerations 103 8 G3 Protection measuresmdashspecial circuits 107 9

Annex H (normative) Electrical segregation 112 10

Annex I (normative) Separation of redundant cables 113 11 I1 Redundant cable systems 113 12 I2 Design considerations 113 13 I3 Separation 114 14

Annex J (normative) Cable pulling tension calculations 115 15 J1 Cable pulling design limits and calculations 115 16 J2 Design limits 115 17 J3 Cable-pulling calculations 118 18 J4 Sample calculation 121 19

Annex K (normative) Handling 126 20 K1 Storage 126 21 K2 Protection of cable 126 22

Annex L (normative) Installation 127 23 L1 Installation 127 24 L2 Supporting cables in vertical runs 129 25 L3 Securing cables in vertical runs 129 26 L4 Training cables 129 27 L5 Cable conductor terminations 129 28

Annex M (normative) Acceptance testing 131 29 M1 Purpose 131 30 M2 Tests 131 31

Annex N (normative) Recommended maintenance and inspection 133 32 N1 General 133 33 N2 Inspections 133 34 N3 Testing methods for metallic cables 134 35 N4 Maintenance 134 36

Annex O (informative) Example for small substation 136 37 O1 General 136 38 O2 Design parameters 136 39 O3 Select cables construction 138 40 O4 Determine raceway routing 139 41 O5 Cable sizing 142 42 O6 Design cable raceway 162 43

Annex P (informative) Example for large substation 170 44 P1 General 170 45




xii

P2 Design parameters 170 1 P3 Select cables construction 175 2 P4 Determine raceway routing 177 3 P5 Cable sizing 184 4 P6 Design cable raceway 214 5

Annex Q (informative) Bibliography 231 6 7




1



Substations 3

IMPORTANT NOTICE IEEE Standards documents are not intended to ensure safety 4 health or environmental protection or ensure against interference with or from other 5 devices or networks Implementers of IEEE Standards documents are responsible for 6 determining and complying with all appropriate safety security environmental health and 7 interference protection practices and all applicable laws and regulations 8

This IEEE document is made available for use subject to important notices and legal 9 disclaimers 10 These notices and disclaimers appear in all publications containing this document and may 11 be found under the heading ldquoImportant Noticerdquo or ldquoImportant Notices and Disclaimers 12 Concerning IEEE Documentsrdquo They can also be obtained on request from IEEE or viewed 13 at httpstandardsieeeorgIPRdisclaimershtml 14

1 Overview 15

The main clauses of the guide are organized by cable type and each of these clauses has been 16 organized to match the general steps involved in the design process for a substation cable 17 system (see Annex A for a flowchart diagram) Common information for each type of cable is 18 placed in the annexes and is referenced from the body of the guide The rationale for 19 organizing the guide in this manner is to make it easier for the user to find the information 20 needed as quickly and efficiently as possible especially for those individuals unfamiliar with 21 the design of cable systems in substations 22

11 Scope 23

This document is a guide for the design installation and protection of insulated wire and cable 24 systems in substations with the objective of helping to minimize cable failures and their 25 consequences High voltage (greater than 35 kV) cable systems are not covered in this guide 26


2 Copyright copy 2015 IEEE All rights reserved


12 Purpose 1

The purpose of this guide is to provide guidance to the substation engineer in established 2 practices for the application and installation of metallic and optical cables in electric power 3 transmission and distribution substations with the objective of helping to minimize cable 4 failures and their consequences This guide emphasizes reliable electrical service and safety 5 during the design life of the substation 6

Regarding cable performance no single cable characteristic should be emphasized to the 7 exclusion of others In addition to good installation design and construction practices an 8 evaluation of cable characteristics is necessary to provide a reliable cable system 9

Solutions presented in this guide may not represent the only acceptable practices for resolving 10 problems 11

This guide should not be referred to or used as an industry standard or compliance standard 12 This document is being presented as a guide to aid in the development of insulated wire and 13 cable system installations in substations 14

2 Normative references 15

The following referenced documents are indispensable for the application of this document 16 (ie they must be understood and used so each referenced document is cited in text and its 17 relationship to this document is explained) For dated references only the edition cited applies 18 For undated references the latest edition of the referenced document (including any 19 amendments or corrigenda) applies 20

Accredited Standards Committee C2 National Electrical Safety Codereg (NESC)1 2 21

IEEE Std 575 IEEE Guide for the Application of Sheath-Bonding Methods for Single-22 Conductor Cables and the Calculation of Induced Voltages and Currents in Cable Sheaths3 4 23

IEEE Std 835 IEEE Standard Power Cable Ampacity Tables 24

3 Definitions acronyms and abbreviations 25

For the purposes of this document the following terms and definitions apply The IEEE 26 Standards Dictionary Online should be consulted for terms not defined in this clause 1 27

ABS Conduit fabricated from acrylonitrile-butadiene-styrene 28

ADSS All-dielectric self-supporting 29

Design life of the substation The time during which satisfactory substation performance can 30 be expected for a specific set of service conditions based upon component selection and 31 applications 32 1IEEE Standards Dictionary Online subscription is available at wwwieeeorggostandardsdictionary




EPC-40 Electrical plastic conduit for type DB applications fabricated from PE or for type 1 DB and normal duty applications fabricated from PVC 2

EPC-80 Electrical plastic conduit for heavy duty applications fabricated from PVC 3

EPT Electrical plastic tubing for type EB applications fabricated from PVC 4

FRE Conduit fabricated from fiberglass reinforced epoxy 5

IED Intelligent electronic device 6

IMC Intermediate metal conduit 7

IRIG-B Inter-range instrumentation groupmdashtime code format B a serial time code format to 8 correlate data with time 9

OPGW Optical power ground wire or optical ground wire 10

RMC Rigid metal conduit 11

ROW Right-of-way a leased or purchased corridor for utility lines 12

STP Shielded twisted pair 13

Type DB Duct designed for underground installation without encasement in concrete 14

Type EB Duct designed to be encased in concrete 15

UTP Unshielded twisted pair 16

4 Control and instrumentation cable 17

41 General 18

Substation control cables are multiconductor cables used to transmit electrical signals with low 19 voltage levels (600 V or less) and relatively low current levels between apparatus [eg power 20 transformers circuit breakers disconnect switches and voltage or current transformers (CTs) 21 etc] and protection control and monitoring devices (eg relays and control switches status 22 lights alarms annunciators etc) Substation control signals may be digital or analog [eg 23 voltage transformer (VT) and CT signals] and the control signal may be continuous or 24 intermittent Control signals may be ldquoonrdquo or ldquooffrdquo with short or long time delays between a 25 change of state 26

The complete substation control cable assembly should provide reliable service when installed 27 in equipment control cabinets conduits cable trenches cable trays or other raceway systems 28 in the electric substation environment 29

Instrumentation cables are multiconductor cables used to transmit low-energy (power-limited) 30 electrical signals with low voltage levels (typically less than 130 V) and relatively low current 31 levels between equipment (usually electronic such as monitors and analyzers) and control 32




equipment for apparatus Signals in instrumentation cables could be continuous or intermittent 1 depending on application 2

As used in this guide instrumentation cables consist of cables transmitting coded information 3 (digital or analog) for Supervisory Controls and Data Acquisition (SCADA) systems 4 substation networks event recorders and thermocouple and resistance temperature detector 5 (RTD) cables 6

In the United States cables are usually designed and constructed in accordance with NEMA 7 WC 57ICEA S-73-532 [B140] Other standards may apply outside the United States 8

As used in this guide leads from CTs and VTs are considered control cables since in most 9 cases they are used in relay protection circuits 10

42 Service conditions (see Annex B) 11

43 Cable selection (see Annex C) 12

431 Conductor sizing 13

The function and location of the control and instrumentation cable circuits affect the conductor 14 size A conductor that is used to connect the CT secondary leads may have different 15 requirements than a cable that is used for the VT secondary leads Outdoor control cables may 16 require larger conductor size to compensate for voltage drop due to the relatively long distance 17 between the equipment and the control building especially for high-voltage and extra-high-18 voltage (EHV) substations Smaller size control cables can be used inside the control building 19 due to the short runs between the panels 20

Because of new designs using microprocessor relays and programmable logic devices there 21 has been a general trend to increase the number of wire terminals on individual panel segments 22 andor racks when metallic cables are used This trend is limited by the practicality of 23 decreasing terminal block and test switch size in order to accommodate the additional 24 terminals Decreasing terminal size creates a practical limit of maximum wire size However 25 violation of minimum wire size requirements could cause voltage drop that results in a failure 26 to trip or current overload that damages the cable Consideration should also be given for 27 minimum sizing for mechanical strength 28

4311 CT circuits 29

CT secondary circuits connect the CT secondaries to protective and metering devices A 30 multiconductor control cable is typically used for a CT secondary circuit which contains all 31 three phases (or one phase only for a single phase CT circuit) and the neutral The CT cable 32 conductor should be sized such that the CT standard burden is not exceeded The CT cable 33 conductor should also be sized to carry the CT continuous thermal rating (eg 10 A 15A) and 34 up to 20 times its normal load current from 01 s to 05 s during a fault (IEEE Std C57133 35 [B113]) 36

Excessive impedance in CT secondary circuits can result in CT saturation The loop lead 37 resistance of a CT secondary should not exceed the required maximums for relay instrument 38




and revenue metering circuits Long cable runs such as those found in large transmission 1 stations can lead to increased impedance values Methods to reduce impedance of the CT 2 secondary circuit include increasing the conductor size and though not preferred running 3 parallel conductors The physical parameters of the termination points should be considered 4 when utilizing large andor multiple conductors 5

4312 VT circuits 6

VT secondary circuits connect the VT secondaries to the protective and metering devices The 7 load current for these devices is very small however the voltage drop should be considered 8 The conductor size should be selected such that the VT standard burden is not exceeded and 9 so that the voltage drop is very small in order to provide the protective and metering devices 10 with the actual voltage at the location of the VTs 11

4313 Trip and close coil circuits 12

Ampacity and voltage drop requirements should be considered when determining the size of 13 the control cables that connect control devices to the trip and close coils of the circuit breakers 14 The conductor size should be capable of carrying the maximum trip coil current and allow for 15 adequate voltage drop based on the trip coil rating The circuit protection should be selected 16 with a trip rating that is significantly higher than the expected duty to help ensure that 17 actuation of a circuit protective device does not result in a failure to trip The trip and close 18 cable conductor should have an ampacity that exceeds the trip rating of the fuse or circuit 19 breaker protecting the circuit 20

4314 Circuit breaker motor backup power 21

Some high-voltage circuit breakers use an acdc spring-charging motor connected to the dc 22 control circuit to operate the breaker mechanism These motors can run on dc if the normal ac 23 station service voltage supply to the circuit breaker is lost The circuit breaker motor supply 24 cable should be selected with a continuous duty ampacity that equals or exceeds the expected 25 ac and dc motor current The conductor should be sized such that the voltage drop at the 26 minimum expected ac and dc supply voltage provides a voltage at the motor within the motor 27 rating 28

The load characteristic of a typical spring charging motor is shown in Figure 1 The typical 29 current draw is much higher than the specified ldquorunrdquo current and should be considered in the 30 design 31




1 Figure 1 mdashSpring charging motor load characteristic 2

4315 Alarm and status circuits 3

Alarm and status circuits carry very small current and voltage drop is not a concern As a 4 result a smaller size conductor can be used for these circuits 5

4316 Battery circuits 6

The station battery will have an operating range with a minimum terminal voltage The battery 7 cable conductors should be selected so that the voltage drop from the battery terminals to the 8 utilization equipment for the expected load current does not result in a voltage below the 9 minimum voltage rating of the utilization equipment DC utilization equipment such as 10 breaker trip coils and protective relays will have a minimum voltage rating for operation A 11 designer should use end of discharge voltage for critical circuits These would include circuit 12 breaker trip and close coils that are required to operate at the end of a batteryrsquos discharge 13 period 14

432 Voltage rating 15

Low-voltage control cable rated 600 V and 1000 V are currently in use For control cables 16 applied at 600 V and below 600 V rated insulation is most commonly used Some engineers 17 use 1000 V rated insulation because of past insulation failures caused by inductive voltage 18 spikes from de-energizing electromechanical devices eg relays spring winding motors The 19 improved dielectric strength of todayrsquos insulation materials prompted some utilities to return to 20 using 600 V rated insulation for this application 21




433 Cable construction 1

The principal components of substation control cables include conductors conductor 2 insulation shielding tape and filler and jacket 3

Conductors for substation control cables may be solid or stranded and may be uncoated 4 copper tin-coated copper or leadlead alloy coated wires Stranded conductors usually consist 5 of 7 or 19 wires for Class B stranding Conductor size typically ranges from 6 to 14 AWG 6 (American Wire Gauge) but other conductor sizes may also be utilized Refer to Annex C 7 Table C3 for parameters of common AWG and circular mil (cmil) sizes Caution should be 8 exercised before using small conductors because of the possibility of mechanical damage 9

Insulation for each conductor in a control cable is made from an extruded dielectric material 10 suitable for use in either wet or dry locations or dry-only locations and at maximum conductor 11 temperatures ranging from 60 degC to 125 degC depending on the type of insulation material 12 utilized Common insulation materials include but are not limited to polyethylene (PE) cross-13 linked PE (XLPE) Types 1 and 2 silicone rubber (SR) synthetic rubber (SBR) and ethylene 14 propylene rubber (EPR) Types 1 and 2 and polyvinyl chloride (PVC) The thickness of 15 insulation varies with the type of insulation material conductor size and voltage rating 16

Shielding is used in some control and instrumentation cables to reduce or eliminate 17 electrostatic interference from outside sources on cable conductors groups of conductors or to 18 reduce or eliminate electrostatic interference between cable conductors or groups of cable 19 conductors within a cable Cable shields typically consist of metal braid helical wrapped tape 20 longitudinally corrugated tape or foil tape that encloses the insulated conductor or group of 21 conductors The shield type can affect the physical characteristics of the cable (flexibility 22 weight etc) and should be considered in relation to the installation requirements A drain 23 wire is frequently found on shielded cables using metal foil tape to aid in the ease of shield 24 termination Shields and drain wires are usually constructed of copper copper alloy or 25 aluminum 26

Tape consisting of dielectric material is utilized to bind and separate layers of construction 27 and fillers made from thermoplastic or other materials are utilized to form a cylindrical shape 28 for most cable assemblies 29

Control and instrumentation cables are provided with an outer jacket that can provide 30 mechanical protection fire resistance or moisture protection Care should be taken to utilize a 31 jacket material that is suitable for the environment in which it is installed Factors to consider 32 include moisture chemicals fire temperature UV exposure personnel occupancy etc 33

Methods for identification of control cable conductors by number with base and tracer colors 34 on each conductor are discussed in Appendix E of NEMA WC 57ICEA S-73-532 [B140] 35 Inner jackets for multi-conductor cables may be color-coded as well (reference Table E-1 36 Table E-2 and Table E-3 of NEMA WC 57ICEA S-73-532 [B140] for guidance) 37




44 Cable raceway design (see Annex E) 1

45 Routing (see Annex F) 2

All control circuits in a substation should be installed in a radial configuration ie route all 3 conductors comprising a control circuit in the same cable and if conduit is used within the 4 same conduit 5

Radial arrangement of control circuitry reduces transient voltages Circuits routed into the 6 switchyard from the control building should not be looped from one piece of apparatus to 7 another in the switchyard with the return conductor in another cable All supply and return 8 conductors should be in a common cable to avoid the large electromagnetic induction possible 9 because of the very large flux-linking-loop arrangement otherwise encountered Also this 10 arrangement helps avoid common impedances that cause differential and common-mode 11 voltages This recommendation is especially important for supply and ground circuits 12

If the substation has a capacitor bank all control cables not specifically associated with 13 capacitor controls or protection should be removed from the immediate area around the 14 capacitor bank to help avoid induction of surges into relaying systems and reduce the risk of 15 possible control cable failure during capacitor bank switching The routing of control cables 16 from capacitor bank neutral CTs or VTs should be kept at right angles with respect to the 17 common neutral for single point grounding and in parallel with the tie to the substation ground 18 for peninsular grounding to minimize induction (ldquoShunt capacitor switching EMI voltages 19 their reduction in Bonneville Power Administration substationsrdquo [B37]) Control cables 20 entering the capacitor bank area should be kept as close as possible to the ground grid 21 conductors in the cable trench or on top of the duct run or in contact with the ground grid 22 conductor if directly buried (see IEEE Std C3799 [B109]) 23

All dc circuits are normally ldquoradialrdquo ie the positive and negative leads (ldquogordquo and ldquoreturnrdquo 24 circuits) are kept within the same cable In alarm and relay circuits where there might be one 25 positive and several negative returns all leads should be in the same jacketed cable 26

In circuits where the positive and negative are in separate cables for specific reasons the 27 positive and negative should be physically close together wherever practical Measures should 28 be taken to avoid shorting the positive and negative such as barriers insulation separate 29 conduits or by landing on non-adjacent terminals etc The positive and negative could be in 30 separate cables due to the required size of the conductors or the physical location of the 31 connected positive and negative terminals such as the circuit between the station battery and 32 the battery charger or DC panel board 33

Where dc motors are connected to the substation control battery as for motor operated 34 disconnect switches or circuit breakers the voltage may be provided by a ldquoyard busrdquo The yard 35 bus is a single pair of large conductors that are sized to supply several or all of the connected 36 motor loads simultaneously 37

46 Transient protection (see Annex G) 38

High energy transients may cause failures in low-voltage substation equipment such as solid-39 state relays transducers measuring instruments and remote terminal units (RTUs) connected 40 at the ends of control or instrumentation cables In a substation environment the high energy 41 sources typically include power- frequency fault currents lightning or switching transients 42




Sometimes these influences are also responsible for erroneous operations of relays causing 1 partial or entire substation shutdown The overvoltages may even damage transient surge 2 suppressor devices such as metal oxide varistors or gas discharge tubes at the terminals 3 Shielded cables are typically applied in higher voltage substations (voltages at 230 kV and 4 higher) or at lower voltages for specific applications including shunt capacitor banks 5 capacitive voltage transformers and gas insulated substations 6

47 Electrical segregation (see Annex H) 7

Segregation of control cables in the substation cable trench or cable tray system is generally 8 not necessary 9

Control cables should not be installed in ducts or trenches containing medium-voltage cables 10 (greater than 1000 V) 11

48 Separation of redundant cable (see Annex I) 12

49 Cable pulling tension (see Annex J) 13

410 Handling (see Annex K) 14

411 Installation (see Annex L) 15

412 Acceptance testing (see Annex M) 16

Control cables should be insulation-resistance tested prior to connecting cables to equipment 17 They may be tested as part of the system checkout 18

413 Recommended maintenance (see Annex N) 19

5 Metallic Communication cables 20

This clause covers the following for metallic communication cables within and to 21 substations 22

1) General 23

2) Service conditions 24

3) Cable selection 25




4) Cable system design 1

5) Transient protection 2

6) Cable pulling 3

7) Handling 4

8) Installation 5

9) Acceptance testing 6

10) Recommended maintenance 7

51 General 8

Substation communications may require multi-conductor metallic communication cables to 9 transfer communication signals at low voltage and current levels using a protocol to the 10 substation andor within the substation Those cables that enter the substation either overhead 11 or underground are addressed by other IEEE standards such as 12

IEEE Std 487 [B77] This standard presents engineering design practices for special 13

high-voltage protection systems intended to protect wire-line telecommunication 14

facilities serving electric supply locations IEEE 487 has been broken down into a 15

family of related documents (ie dot-series) segregated on the basis of technology Std 16

487 contains the General Considerations common to the entire lsquodot-series The 17

documents in the entire series are 18

a) IEEE Std 487 [B77] General Considerations 19

b) IEEE Std 4871 [B78] for applications using On-Grid Isolation Equipment 20

c) IEEE Std 4872 [B79] for applications consisting entirely of optical fiber cables 21

d) IEEE Std 4873 [B80] for applications of hybrid facilities where part of the 22

circuit is on metallic wire-line and the remainder of the circuit is on optical fiber 23

cable 24

e) IEEE Std 4874 [B81] for applications using Neutralizing Transformers 25

f) IEEE Std 4875 [B82] for applications using Isolation Transformers 26

IEEE Std 789 [B88] This standard covers the appropriate design requirements 27

electrical and mechanical parameters the testing requirements and the handling 28

procedures for wires and cables used principally for power system communications 29

and control purposes that are to be installed and operated in high-voltage 30

environments where they may be subjected to high voltages either by conduction or 31

induction coupling or both Coaxial and fiber optic cables except for those used in 32

Ethernet applications are specifically excluded 33




This guide addresses the design and installation of metallic cable types wholly contained 1 within a substation 2

a) Telephone cables and other multiconductor communications cables that are not serial 3

Ethernet or coaxial cables 4

b) Serial cables (RS232 RS485 and Universal Serial Bus (USB)) 5

c) Ethernet cables 6

d) Coaxial cables 7

This clause also addresses the different terminations used for these types of cables Metallic 8 communication cables are typically unshielded twisted pairs (UTP) such as many types of 9 Ethernet and serial telephone and Ethernet cables Shielded twisted pairs (STP) are also 10 common IEC 11801 [B115] attempts to standardize the definitions for different combinations 11 of cable screening (unscreened foil screened braid screened braid and foil screened) and pair 12 shielding (unscreened or foil screened) and number of twisted conductors (twisted pair and 13 twisted quad) 14

511 Telephone cable and multiconductor communication cables 15

These types of cables have been essential for providing voice and data circuits to substations 16 for decades Phone cable types can be dictated by whether the connection is dial-up or leased 17 line In many cases two copper wires (tip and ring) for each dial-up telephone line are run 18 from a substation to a local telephone companyrsquos point of presence (POP) usually addressing 19 the GPR design issues in IEEE Std 487 [B77] Tip and ring refers to the two wires or sides of 20 an ordinary telephone line where tip is the ground side (positive) and ring is the battery 21 (negative) side 22

Phone circuits are typically identified with the Plain Old Telephone Service (POTS) or voice 23 grade communications which are limited in bandwidth to between 300 and 3400 Hz so 24 modems provide digital service over the analog phone lines POTS lines are part of the public 25 switched telephone network (PSTN) Today the PSTN has migrated from the original days of 26 copper telephone lines to include fiber optic cables microwave transmission links cellular 27 networks communications satellites and undersea cables The PSTN connects these together 28 in switching centers allowing any telephone in the world to communicate with any other The 29 PSTN is now almost entirely digital in its core and includes mobile as well as fixed telephones 30

Multiconductor communication cables may also be used for pilot wire protection using pilot 31 wires which may use any combination of private wires and telco wires Pilot wire connects 32 together two or more protective relays where dc or ac signals are connected together using 33 pilot wires where ac pilot wire protection is mostly akin to modern line differential protection 34 A relay at each end of the protected circuit converts the current flow at one line terminal to a 35 composite single-phase quantity Because the two relays are connected by pilot wires the 36 quantity at one terminal can be electrically compared with the quantity at the other terminal If 37 the correct match between terminals does NOT occur a trip of the circuit breakers at each 38 terminal will be initiated More information on pilot wire systems exists in IEEE Std 487 39 [B77] and IEEE Std C37236 [B111] Once inside a substation pilot wire cables will be run 40 from some terminal point to the end device 41

In addition to POTS lines and pilot wires multiconductor communications cables are used for 42 dedicated four-wire leased line phone circuits typically providing low-speed serial SCADA 43




communications and teleprotection applications as described in IEEE Std C37236 [B111] 1 Unlike dial-up connections a leased line is always active is not connected to a telephone 2 exchange (no phone number) does not provide DC power dial tone busy tone or ring signal 3 The fee for a connection is a fixed monthly rate The primary factors affecting the monthly fee 4 are distance between end points and the speed of the circuit Because the connection is 5 dedicated the carrier can assure a given level of quality typically considered class A B or C 6 service As defined in IEEE Std C3793 [B108] and IEEE Std 487 [B77] Class A is non-7 interruptible service performance (must function before during and after the power fault 8 condition) class B is self-restoring interruptible service performance (must function before 9 and after power fault condition) and class C is interruptible service performance (can tolerate 10 a station visit to restore service) Not all leased lines are four wire circuits Leased lines can 11 transmit full duplex (transmit and receive at the same time) or half duplex (transmit or receive 12 one at a time) Leased lines can be synchronous where the data is transmitted at a fixed rate 13 with the transmitter and receiver synchronized Leased lines are not just limited to low-speed 14 serial communications 15

Phone cable conductors regardless of dial-up or leased line are individually insulated The 16 conductors range in size from 22 to 26 AWG copper The conductors are twisted and may be 17 shielded in pairs from as few as 2 pairs up to hundreds of pairs and in groups of 25 pairs The 18 twisted pairs also have a de-facto standard color code for up to 25 pairs Cables over 25 pairs 19 have the first 25 pairs isolated with ribbons using the colors of the color code starting with the 20 first color code the second 25 pairs with a ribbon with the second color code and so on until 21 all cables are identified into a ldquosuperrdquo binder Those super binders can then be combined using 22 the same color code scheme too forming even larger cables 23

512 Serial cables 24

Serial cables have traditionally been essential for the transfer of basic digital data signals to 25 and within a substation Typically serial cables do not enter a substation but can be abundant 26 within a substation The conductors are twisted and can be STP or UTP with or without 27 overall shielding Serial communications is commonly known as ldquoRS232rdquo and ldquoRS485rdquo The 28 official standards for each (TIA-232-F and TIAEIA-485-A) do not define specific cable 29 construction requirements only cable characteristics such as capacitance Both RS232 and 30 RS485 cables are typically unshielded but there may be an overall cable shield andor braid 31 The cables may have twisted pairs (more typical of RS485) or not (more typical of RS232) 32

Serial cables may need to support baud rates between 1200 to 115 kbps for RS232 and can 33 extend to over 1 Mbps for RS485 Baud rates are typically limited by several factors including 34 cable length and capacitance See IEEE C371 [B106] 35

5121 Serial RS232 cables 36

RS232 cables typically have between 2 and 9 conductors depending upon what signals are 37 required by the devices being connected together The standard actually specifies 20 different 38 signal connections typically substation intelligent electronic devices (IEDs) today use only 39 transmit data (TX) receive data (RX) and signal ground others that may be included are 40 request to send (RTS) and clear to send (CTS) and are commonly referred to as ldquohardware 41 handshakingrdquo signals When RTS and CTS are not present software flow control or 42 handshaking is used Connections with modems will typically have even more signals and 43 conductors Cables should be properly selected in tandem with the connectors used as 44 discussed in clause 515 45




RS232 devices are classified as either data communications equipment (DCE) or data terminal 1 equipment (DTE) DCE devices are digital devices that connect to a communications line for 2 the purpose of data transfer without regard to its content (eg a modem) DTE devices are 3 digital devices that transmit or receive data and require communications equipment for the 4 data transfer DTE devices terminate a communication line and require DCE equipment for the 5 data transfer DCE devices are connected directly to the communication circuit used between 6 two DTE devices DTE devices usually use a male plug connector and DCE devices a female 7 connector As a general rule nine pin DTE devices transmit on pin 3 and receive on pin 2 and 8 nine pin DCE devices transmit on pin 2 and receive on pin 3 Avoiding the use of DCE 9 equipment is very common between two devices This is accomplished through the use of a 10 null modem cable that acts as a DCE between the devices by swapping the corresponding 11 signals (such as TX-RX and RTS-CTS) 12


True RS485 cables have three conductors two for the communication bus and one for signal 14 ground There does exist ldquo4 wirerdquo RS485 but these do not strictly adhere to the TIAEIA-485-15 A standard RS485 has three signal wires typically denoted as 16

a) ldquoArdquo ldquo-ldquo and ldquoTxD-RxD-rdquo 17

b) ldquoBrdquo ldquo+ldquo and ldquoTxD+RxD+rdquo 18

c) ldquoSCrdquo ldquoGrdquo 19

This does not mean that all vendors denote them the same way which means care is required 20 in wiring together devices that are from different vendors Re-wiring an RS485 circuit is not 21 uncommon because of this labeling problem and good documentation is recommended 22 especially when vendorsrsquo implementations do not agree and the A line should be connected to 23 the B line for the circuit to work Care should be used to not use the shield as the third 24 conductor (ldquoSCrdquo or ldquoGrdquo) as this may introduce noise into the communications circuit and 25 cause the communications to fail when noise becomes an issue Optical isolation provided in 26 many devices may remove the need for the signal ground and circuits may combine devices 27 that use optical isolation and those that do not 28

Serial cable conductors are typically individually insulated and range in size from 22 to 26 29 AWG copper The cables may be assembled with terminations may be twisted may have 30 shielded pairs may have an overall shieldfoilbraid and may have armor - in any 31 combination The shield protects the signal conductors from interference A bare drain 32 conductor may be present to provide a grounding connection for the shield 33

5123 USB cables 34

USB was designed to standardize the connection of typical computer peripherals such as 35 keyboards pointing devices and printers but also digital cameras portable media players disk 36 drives and network adapters USB is used to communicate and to supply low-voltage dc 37 power It has become commonplace on other devices such as smart phones and video game 38 consoles USB has effectively replaced a variety of earlier communication interfaces such as 39 serial and parallel ports as well as separate power sources for portable devices because of the 40 power supply allowed in the specification USB USB 20 USB 30 and USB wireless 41 specifications are maintained by the USB Implementers Forum and are available for 42 download 43




USB 20 is most common today where the specification specifies a cable with four 1 conductors two power conductors and two signal conductors plus different connector styles 2 The cable impedance should match the impedance of the signal drivers The specification 3 allows for a variable cable length where the maximum cable length is dictated by signal pair 4 attenuation and propagation delay as well as the voltage drop across the ground conductor The 5 minimum wire gauge is calculated from the current consumption There are differences 6 between high-full speed cables and low-speed cables most notably the required shield in the 7 former and an optional shield in the latter also the required drain wire in the latter The 8 specification requires a shield be terminated to the connector plug for completed assemblies 9 The shield and chassis are bonded together The user-selected grounding scheme for USB 20 10 devices and cables is to be consistent with accepted industry practices and regulatory agency 11 standards for safety and EMIESDRFI 12

USB cable may be used for applications of RS232 andor RS485 communication provided 13 there is a proper converter from USB to RS232RS485 These converters are commonplace 14 today Other applications which may be critical are for peripheral connections from 15 computers to keyboards pointing devices and touch screens Care should be used in selecting 16 USB cables and converters that meet the environmental requirements of the application 17 Rugged USB cables and connectors are available but the connectors may be vendor-specific 18 and may not be supported by devices Cable lengths should be carefully considered given the 19 performance-based length specification It is possible to convert USB to Ethernet or extend 20 USBrsquos range by converting to Ethernet cable given the proper converter 21

513 Ethernet cables 22

There are several designations for communication cables which originally started out as 23 ldquolevelsrdquo and eventually became known as categories and then abbreviated to ldquoCATrdquo (for 24 category) designations that today primarily apply to Ethernet cables Some are still official 25 categories maintained by the TIAEIA Cable category characteristics and use are listed below 26




Table 1 mdashCable characteristics or ldquoCATrdquo cables 1

Category Use Standard Frequency BandwidthMaximum

Distance (m)

1

Known as ldquovoice graderdquo UTP copper circuits used for POTS (plain old telephone service)

No standard exists

Originally called Anixter

level 1

Less than 1 MHz

2

Low speed UTP cabling for older computer networks telephone networks and is no longer commonly used

No standard exists

Originally called level 2 by Anixter

4 MHz 4 Mbps

3

Typically UTP cabling although also available in screened twisted pair commonly called ldquostation wirerdquo that was the first cabling category standardized by the TIAEIA and commonly used on 10BaseT Ethernet networks in the 1990s

TIAEIA-568-C

16 MHz 10 Mbps100 Ethernet 10BASE-T

4

UTP cabling briefly used for 10BaseT networks that was quickly superseded by CAT55e cable that is no longer recognized by the TIAEIA

20 MHz 16 Mbps

5

Cabling that is typically UTP but also could be STP can also carry video telephony and serial signal and is no longer recognized by the TIAEIA

Originally defined in

TIAEIA-568-A

100 MHz10 Mbps

100 Mbps 1000 Mbps

100 Ethernet 10BASE-T

100Base-TX 1000BaseT

5e

Enhanced CAT5 cabling that can be 24-26 awg UTP or STP which improved upon CAT5 cablersquos performance and resulted in CAT5 cable being no longer recognized by the TIAEIA


TIAEIA-568-A-5 in 1999

100 Mhz10 Mbps

100 Mbps 1000 Mbps



6Standard cabling for gigabit Ethernet networks is 22-24 awg UTP or STP

TIAEIA-568-C

250 MHz

10 Mbps 100 Mbps

1000 Mbps 10GBaseT


100Base-TX 1000BaseT 55

10GBaseT

6AAugmented CAT6 cabling can be UTP or STP

TIAEIA-568-C

500 MHz


100Base-TX 1000BaseT 10GBaseT 2

3




Cat 7 cable with four individually-shielded pairs inside an overall shield has been proposed 1 but is not in common use today Cat 7 is designed for transmission frequencies up to 600MHz 2 which should enable it to carry 10-Gigabit Ethernet (10GBaseT) but requires a redesigned RJ-3 45 connector (called a GG45) to achieve this speed 10GBaseT networks are not yet widely 4 available and may not be able to compete with fiber optic networks 5

514 Coaxial cables 6

Coaxial cable consists of 7

a) An outer jacket 8

b) An outer shield consisting of one or more layers of braid andor foil 9

c) A dielectric insulator such as polyethylene (PE) 10

d) An inner solid or stranded conductor 11

The outer shield of foil andor braid acts as both a shield and a return path conductor An ideal 12 shield would be a perfect conductor without bumps gaps or holes and connected to a perfect 13 ground However a smooth solid and highly conductive shield would be heavy inflexible 14 and expensive Thus cables compromise between shield effectiveness and flexibility which 15 may have a bearing on cost Braided copper wire for the shield allows the cable to be flexible 16 but it also means there are gaps in the shield layer thus reducing the shieldrsquos effectiveness Foil 17 improves the coverage when combined with the braid 18

There are names for coaxial cables originating from military uses in the form ldquoRG-rdquo or ldquoRG-19 Urdquo The RG designation stands for Radio Guide the U designation stands for Universal 20 These date from World War II and were listed in MIL-HDBK-216 published in 1962 which is 21 now withdrawn The RG unit indicator is no longer part of the military standard now MIL-C-22 17 Some of the new numbers have similar characteristics as the old RG numbers One 23 example is Mil-C-172 and RG-6 cables These cables are very similar however Mil-C-172 24 has a higher working voltage at 3000 V (versus 2700 V for RG-6) and the operating 25 temperature of Mil-C-172 is much higher at 185 degC (versus 80 degC for RG-6) 26

The RG designations are still common Cable sold today under any RG label is unlikely to 27 meet military MIL-C-17 specifications Subsequently there is no standard to guarantee the 28 electrical and physical characteristics of a cable described as ldquoRG- typerdquo Today RG 29 designators are mostly used to identify compatible connectors that fit the inner conductor 30 dielectric and jacket dimensions of the old RG-series cables Because of these issues care 31 should be used to select the proper cable based upon the application and installation 32 requirements for temperature and other environmental factors 33

Most coaxial cables have a characteristic impedance of 50 52 75 or 93 Ω 34

Table 2 mdashCommon coaxial RG designations 35

Cable type Use RG-6 A 75 Ω cable type Commonly used for satellite clock antennas

Commonly used for cable television (CATV) distribution coax used to route cable television signals to and within homes CATV distribution coax typically has a copper-clad steel (CCS) center conductor and an aluminum foilaluminum braid shield with coverage around 60




RG-6 type cables are also used in professional video applications carrying either base band analog video signals or serial digital interface (SDI) signals in these applications the center conductor is ordinarily solid copper the shielding is much heavier (typically aluminum foil95 copper braid) and tolerances are more tightly controlled

RG-8 RG-8 is a 50 Ω cable used in radio transmission or in computer networks RG-58 is a larger diameter cable than RG-8

RG-11 A 75 Ω cable type RG-58 RG-58 is a 50 Ω cable Commonly used for IRIG-B distribution radio

transmission computer networks or power line carrier applications RG-58 is a smaller cable than RG-8

RG-59 A 75 Ω cable originally used for CATV but is being replaced by RG-6 RG-213 A 50 Ω cable used for power line carrier applications 1

Advantages of coaxial cable include the following high bandwidth low signal distortion low 2 susceptibility to cross-talk and noise low signal losses and greater information security 3 However coaxial cable is more difficult to install heavier and does not have the flexibility 4 offered by twisted pair cables 5

The shield of a coaxial cable is normally grounded so if even a single bit of shield touches the 6 center conductor the signal will be shorted causing significant or total signal loss This occurs 7 at improperly installed end connectors and splices In addition the connectors require proper 8 attachment to the shield as this provides the path to ground for the interfering signal Despite 9 being shielded coaxial cable can be susceptible to interference which has little relationship to 10 the RG designations (eg RG-59 RG-6) but is strongly related to the composition and 11 configuration of the cable shield Foil shielding typically used with a tinned copper or 12 aluminum braid shield with anywhere from 60 to 95 coverage The braid is important to 13 shield effectiveness because the braid 14

a) Is more effective than foil at preventing low-frequency interference 15

b) Provides higher conductivity to ground than foil and 16

c) Makes attaching a connector easier and more reliable 17

For better shield performance some cables have a shield with only two braids as opposed to a 18 thin foil shield covered by a wire braid ldquoQuad-shieldrdquo cables use four alternating layers of foil 19 and braid which is typically used in situations involving troublesome interference Quad-20 shield is less effective than a single layer of foil and single high-coverage copper braid shield 21 Other shield designs reduce flexibility in order to improve performance 22

Typical uses of coaxial cable are for transmission of radio frequency signals The most 23 common uses in substations are for antenna connections to satellite clocks and satellite clock 24 timing signal distribution using IRIG-B communication Other substation uses include 25 microwave radio and power line carrier (PLC) applications Equipment manufacturers should 26 be contacted to provide guidance on application-specific cable selection 27

515 Terminations 28

Terminations are used to connect communication cables to the various IEDs for the purpose of 29 communications There are various types of terminations A different type of termination can 30 be used on either end of the cable Regardless of the terminations used for communication 31 cables care should be taken to match each signal assigned to each conductor terminal or pin 32




on each end of the communication cable This helps ensure that the communications work 1 properly Terminals and signals should be identified clearly on drawings typically in common 2 details especially when a custom cable and termination are required for the application These 3 are typically referred to pin-out diagrams Also note that while there are common connectors 4 for serial cables and Ethernet cables as discussed the presence of the one of these connectors 5 does not guarantee the port signaling is the typical type This is especially true for RJ45 ports 6 which are commonly used for Ethernet RS232 or RS485 communications 7

5151 Punchdown blocks 8

Phone cables are typically terminated to a 66-block punchdown block common to telephone 9 systems or a 110-block punchdown block common to higher speed cable terminations for 10 CAT 5 and 6 cables A punchdown block is named because the solid copper wires are 11 ldquopunched downrdquo into short open-ended slots that are a type of insulation-displacement 12 connectors These slots typically cut crosswise across an insulating plastic bar with two sharp 13 metal blades that cut through the wirersquos insulation as it is punched down These blades hold 14 the wire in position and make the electrical contact with the wire as well A punchdown tool is 15 used to push the wire firmly and properly into the slot making the termination easy because 16 there is no wire stripping and no screw terminals Patch panels are commonly replacing 17 punchdown blocks for non-voice applications because of the increasing performance demands 18 of Ethernet cabling 19

5152 Terminals 20

A terminal strip may be used to land the communication conductors These types of 21 connections are typically used for terminating RS485 cables but may also be seen for RS232 22 connections and rarely for Ethernet connections or coaxial connections Care should be used to 23 properly identify the conductor signals and terminal block labels so as to properly associate 24 them with the signals for the terminal connection being used 25

5153 DB connectors 26

RS232 cables are typically terminated in connectors commonly called DB9 or DB25 today 27 The original RS232 connector was a 25 pin connector but that connector is much larger than 28 the connector associated with the DB25 connector seen today The D-subminiature connector 29 was invented by Cannon 1952 with an operating temperature between -54 degC and 150 degC The 30 product had a standard series prefix of ldquoDrdquo and different shell sizes (A B C D E) followed 31 by the number of pinssockets Connectors of six different sizes were later documented in 32 MIL-24308 (now withdrawn) with a temperature range from -55 degC to +125 degC A similar 25 33 pin connector is defined in ISOIEC 60211 without any temperature range The DB connectors 34 with crimp connectors are standardized in IEC 60807-3 and solder style connectors in IEC 35 60870-2 both with five shell sizes for 9 15 25 37 and 50 pins The temperature ranges from -36 55 degC to +125 degC and -55 degC to +100 degC for IEC 60870-3 IEC 60870-2 adds another 37 temperature range from -40 degC to +100 degC 38

Each DB connector is designated as male (plug) or female (jack) The pins may be crimped or 39 soldered onto the conductors in the cable The most common connectors are 9 pins (DB9) 15 40 pins (DB15) 25 pins (DB25) 37 pins (DB37) and 50 pins (DB50) though others are used 41 Serial cables have various combinations of gender and pins such as a DB9 female connector 42 on one end (DB9F) and a DB25 male connector on the other (DB25M) In addition just 43 because a cable has connectors with nine pins on both ends this does not mean all nine pins 44




are actually connected through the cable How the pins are connected through the cable may 1 only be discoverable by pinning out the cable with a simple ohm meter to test connectivity 2 between one pin on one end with each pin on the other end The pin out may be specified on a 3 specification sheet or drawing Providing a pin out diagram is typically required when 4 requesting a custom cable from a cable manufacturer A pin out diagram also validates that 5 the selected cable will actually work with the signals on the pins for the connected IEDs 6

Use care when connecting serial ports together via serial cables because the signal pins may 7 not be properly connected by the cable possibly resulting in damage to the communication 8 port that may not be readily repaired 9

Please reference the vendorrsquos documentation to properly identify the pin signal definitions for 10 both cable connectors and IEDs 11

12 Figure 2 mdashTypical serial DB-style connectors 13

5154 RJ (registered jack) connectors 14

Registered jack (RJ) connectors typically terminate communication cables and jacks located 15 on devices The RJ designation describes the physical geometry of the connectors and a wiring 16 pattern in the jack inspection of the connector will not necessarily show which registered jack 17 wiring pattern is used The same modular connector type can be used for different registered 18 jack connections While registered jack refers to both the female physical connector (modular 19 connector) and its wiring the term is often used loosely to refer to modular connectors 20 regardless of wiring or gender The six-position plug and jack commonly used for telephone 21 line connections may be used for RJ11 RJ14 or even RJ25 all of which are names of interface 22 standards that use this physical connector The RJ abbreviations only pertain to the wiring of 23 the jack (hence the name registered jack) it is commonplace but not strictly correct to refer to 24 an unwired plug connector by any of these names 25

The types of cable connectors are a plug type of connector when the device has a receptacle 26 They are typically used for telephone and network type applications but can be used for serial 27 ports and other ports as well Some common designations are shown below TIA-1096-A 28 specifies some temperature range for the connectors based upon change in contact resistance 29 between -40 degC and +66 degC under varying humidity conditions There is no specification for 30 vibration only mating and unmating cycles 31

IEC 60603-7 specifies a temperature ranges and vibration conditions The temperature range is 32 between -40 degC and +70 degC for 21 days based upon climatic category 4007021 from IEC 33 61076-12006 The vibration requirements are taken from IEC 60512 with a frequency range 34 between 10 Hz to 500 Hz Amplitude at 035 mm acceleration at 50 ms-2 and 10 sweeps per 35 axis 36

For Ethernet cables TIA-598-C [B6] requires connecting hardware be functional for 37 continuous use over the temperature range from -10 to 60 degC 38




Table 3 mdashCharacteristics of RJ connectors 1

Common Name

Wiring Connector Usage

RJ11 RJ11C RJ11W

6P2C For one telephone line (6P4C if power on second pair) RJ11W is a jack from which you can hang a wall telephone while RJ11C is a jack designed to have a cord plugged into it

RJ45 8P8C 8P8C modular connectors are typically known as ldquoRJ45rdquo an informal designation for TIA-568A or TIA-568B jacks including Ethernet that is not the same as the true RJ45RJ45S The shape and dimensions of an 8P8C modular connector are specified in TIA-1096-A but this standard does not use the term 8P8C (only as a miniature 8 position plug unkeyed and related jack) and covers more than just 8P8C modular connectors however the 8P8C modular connector type is described in TIA-1096-A with eight contacts installed The international standard for the 8P8C plug and jack for ISDN is ISO-8877 For Ethernet cables the IEC 60603-7 series specifies not only the same physical dimensions as the 8P8C for shielded and unshielded versions but also high-frequency performance requirements for shielded and unshielded versions of this connector for frequencies up to 100 250 500 600 and 1000 MHz

RJ48 RJ48 8P8C Used for T1 and ISDN termination and local area data channelssubrate digital services

RJ48 RJ48C 8P8C Commonly used for T1 lines and uses pins 1 2 4 and 5 RJ48 RJ48S 8P8C

keyed Commonly used for local area data channelssubrate digital services and carries one or two lines

RJ48 RJ48X 8P8C with shorting bar

A variation of RJ48C containing shorting blocks in the jack creating a loopback used for troubleshooting when unplugged The short connects pins 1 and 4 and 2 and 5 Sometimes this is referred to as a ldquosmart jackrsquo

2

Figure 3 shows a generic 8P8C receptacle 3

Most vendors do not provide detailed specifications on the RJ45 jack provided in their devices 4 In some situations where temperature or vibration is a concern the vendor should be consulted 5 regarding their specifications 6

7 Figure 3 mdashGeneric 8P8C receptacle 8

5155 Coaxial connectors 9

Coaxial cables are frequently terminated using different styles of connectors including BNC 10 (Bayonet Neill Concelman) TNC (threaded NeillndashConcelman) and N The BNC connectors 11 are miniature quick connectdisconnect connectors that feature two bayonet lugs on the female 12 connector mating is achieved with only a quarter turn of the coupling nut BNCs are ideally 13 suited for cable termination for miniature-to-subminiature coaxial cable (RG-58 RG-59 etc) 14




The BNC was originally designed for military use and is widely used in substations for IRIG-1 B time distribution signals The connector is widely accepted for use up to 2 GHz The BNC 2 uses a slotted outer conductor and some plastic dielectric on each gender connector This 3 dielectric causes increasing losses at higher frequencies Above 4 GHz the slots may radiate 4 signals so the connector is usable but not necessarily stable up to about 11 GHz BNC 5 connectors exist in 50 and 75 Ω versions matched for use with cables of the same 6 characteristic impedance BNC connectors are typically found on IEDs for IRIG-B input 7 although terminal blocks are also used on some IEDs for IRIG-B input 8

The TNC connectorrsquos impedance is 50 Ω and the connector operates best in the 0ndash11 GHz 9 frequency spectrum and has better performance than the BNC connector TNC connectors can 10 be found on some satellite clocks for the coaxial cable connection to the antenna 11

The N connector is a threaded connector used to join coaxial cables It was one of the first 12 connectors capable of carrying microwave-frequency signals Originally designed to carry 13 signals up to 1 GHz todayrsquos common N connector easily handles frequencies up to 11 GHz 14 and beyond 15

MIL-PRF-39012 covers the general requirements and tests for RF connectors used with 16 flexible cables and certain other types of coaxial transmission lines in military aerospace and 17 spaceflight applications 18

Also used with coaxial connectors are tee connectors that allow coaxial cable runs to be 19 tapped These are commonly found in IRIG-B time distribution systems There also may be a 20 need to convert from coaxial cable to TSP cable which can be accomplished by using 21 breakout connectors Care should be used in properly terminating the coaxial cable with a 22 termination resistor Work is underway to create a recommended practice for cabling the 23 distribution of IRIG-B signals within substations 24

52 Service conditions 25

For typical service conditions (or environmental performance) for metallic communication 26 cables serving and within substations and switching stations see Annex B Typical 27 environmental ratings are discussed in Annex B but the specific types of metallic 28 communication cables (ie serial and Ethernet cables) and terminations are discussed 29 previously in this clause 30

Environmental performance for indoor and outdoor cable will likely impact the cable jacket 31 For indoor cables the NEC [B144] divides a buildingrsquos inside area into three types of sections 32 plenums risers and general purpose areas A plenum area is a building space used for air flow 33 or air distribution system which is typically above a drop ceiling or under a raised floor that is 34 used as the air return for the air handling Cables burning in the plenum space could give off 35 toxic fumes and the fumes could be fed to the rest of the building by the air handling system 36 potentially injuring people in other areas of the building A riser area is a floor opening shaft 37 or duct that runs vertically through one or more floors Anything that is not riser or plenum is 38 general purpose 39

The NEC [B144] designates the following metallic communication cable types 40

a) CMP as communications plenum cable 41

b) CMR as communications riser cable 42




c) CMG as communications general-purpose cable 1

d) CM as communications general-purpose cable 2

e) CMX as communications cable limited use 3

f) CMUC as under-carpet communications wire and cable 4

Note that none of these specifically include ldquotray cablerdquo in the name Tray-rated metallic 5 communication cable is a complicated topic as the NEC [B144] allows CMP CMR CMG 6 and CM cables to be installed in cable trays without any ratings However there is no exact 7 specification of tray rated cable leaving the user to define the requirements of tray rated cable 8 Ultimately a tray rated metallic cable (and perhaps fiber optic cable) is likely to conform to 9

a) NEC Article 318 [B144] ldquoCable Traysrdquo and Article 340 ldquoPower and Control Cable 10

Type TCrdquo 11

b) Flame tests per UL 1277 [B168] ICEA T-29-520 [B47] ICEA T-30-520 [B48] and 12

the 70000 BTU ldquoCable Tray Propagation Testrdquo per IEEE Std 1202 [B97] 13

c) Rated 600 V 14

Outside plant cable can be run inside a building per the NEC [B144] requirements up to 1524 15 m (50 ft) Outside plant cables generally differ from inside plant cables in the jacket and any 16 filling compound or gel used to limit the ingress of water into the cable Conductor 17 deterioration from water will cause noise on metallic communication cables either from the 18 cable or from the termination 19

Service conditions include ground potential rise (GPR) for metallic communication cables 20 originating from outside the substation 21

Any metallic communication cable connection to a substation or switchyard from outside the 22 substation is where IEEE Std 487 [B77] applies Here GPR should be considered in order to 23 protect sensitive equipment This consideration requires coordination with the engineering 24 staff of outside entities (eg telephone company) to help ensure that appropriate isolation 25 equipment is installed and that offsite equipment is adequately protected from unacceptable 26 voltage increases in the event of a fault See IEEE Std 487 [B77] for the IEEE recommended 27 practice for protecting wire-line communication facilities serving substations or switchyards 28

Even inside a substation GPR and other environmental effects may also be a concern when 29 using metallic communication cables IEEE Std 1615 [B104] provides recommendations on 30 when to use fiber and metallic cables within a substation 31

53 Metallic cable selection 32

Selection of metallic communication cable types depends upon the application used for the 33 cable for example RS232 RS485 or Ethernet communications In selecting a cable generally 34 the larger conductor sizes help reduce the effects of resistance on signal transmission but 35 many standards dictate the size range of the conductors as indicated previously 36




Ultimately metallic cable selection depends upon meeting the installation requirements as 1 noted above and compliance with the type of communication circuits involved This clause 2 specifically addresses the following types 3

a) Telephone cable (and multiconductor cable that is not serial Ethernet or coaxial) 4

b) Serial cable 5

c) Ethernet cable 6

d) Coaxial cable 7

Note that it is now common to use Ethernet cable for both serial cables and telephone cables 8 Using Ethernet cable in this manner requires care to confirm not only the proper termination of 9 the cable but also the connection of the cable to the correct communication port (ie it 10 becomes very easy to connect a cable used for serial communications into an RJ45 plug 11 function as an Ethernet port) 12

Selection of RS232 and RS485 serial cables depends upon how many signal wires are required 13 by the communication ports what shielding is required the transmission speed the distance 14 and the environmental requirements The RS232 and RS485 standards are protocol agnostic 15 not defining any kind of message structure These standards were only designed to connect 16 devices together so they could communicate using protocols RS232 is typically used for point 17 to point communications that may be just a simple ASCII protocol or more complex 18 masterslave protocol RS485 is selected for point to multipoint communications using a 19 protocol that is masterslave in function See Annex H of IEEE Std C371 [B106] for more 20 information on RS232 and RS485 circuits including their distance limitations correct shield 21 termination practices and the options available for extending the cable length 22

Selection of the termination method is heavily dependent upon end devices Some devices 23 provide serial port connections that are DB9F terminal strips or RJ45 connectors There may 24 or may not be a difference between what signals are present in each termination type It is 25 highly recommended to use the termination form factor most common with the 26 implementation DB9F when using serial RS232 terminal block when using RS485 and RJ45 27 when using Ethernet However this may not be the optimum approach for a particular 28 application because signal pins are not available in one form factor versus another 29

In other cases such as IRIG-B distribution there may be multiple port types supported by the 30 IEDs and satellite clock For example the satellite clock IRIG-B output may only support a 31 BNC connector and the IEDs support a variety of BNC terminal block and DB9 connectors 32 One approach here might be to use coaxial cable as the main distribution bus with breakout 33 cables to support the connection to the IEDs Use of a coaxial cable may provide added noise 34 immunity and provide differentiation between other communication cables It may also be 35 decided that STP cable is the better approach with appropriate converters to each of the IEDs 36 and satellite clock 37

54 Cable system design 38

Cable system design includes issues related to raceway routing segregation and separation 39




541 Raceway design 1

Annex E contains more details on electrical cable raceway design noting that when metallic 2 communication cables are installed in raceway without other electrical cables raceway fill is 3 not required (Article 800 of NEC 2011 [B144]) Fill ratios for metallic Ethernet cables may be 4 in accordance with TIA-569-C [B5] pathway percent fill requirement when installed in a 5 raceway without current carrying conductors 6

The metallic communication cable raceway will be different inside and outside the substation 7 control building Inside the control building use of cable tray and conduit is common When 8 installed in its own raceway that raceway should be supported per TIA-569-C [B5] NEC 9 Article 800 [B144] contains the installation requirements for raceways that support metallic 10 communication cables 11

In the substation yard use of cable tray conduit underground duct and a trench system is 12 common Conduit and duct offers protection from crushing ground disruption rodents and 13 other environmental abuse In addition the cable is easier to replace or upgrade in the future 14 Several methods and types of conduit systems are used For example one configuration 15 includes pre-manufactured segregated ducts or large ducts with multiple plastic high-density 16 PE ldquoinner ductsrdquo installed inside The inner ducts can be smooth walled or corrugated either 17 longitudinally or horizontally 18

One of the types of conduit used for buried communication cable is the continuous-reeled type 19 Such continuous duct is popular because it is relatively inexpensive and may offer enough 20 protection to allow the use of less expensive cable constructions 21

542 Routing 22

Metallic communication cables are typically routed in a manner to increase electrical 23 segregation as well as physical damage in order to maintain a high level of availability Also 24 see Annex F for more routing information common to communication cables regardless of 25 type Routing for diversity or redundancy is discussed in Annex I 26

543 Electrical segregation 27

If it is necessary to run communications cable in parallel with control or power cable it is 28 recommended that the separation be as great as possible and consideration given to using a 29 shielded cable While separation standards exist for Ethernet cabling it is good practice to 30 follow the same requirements for all other metallic communication cables Metallic 31 communication cables can be installed in a route that is parallel to control cable and AC power 32 distribution cables TIA-569-C [B5] provides general guidelines for separation of metallic 33 Ethernet cabling from branch power circuits in an office environment or a MICE E1 34 classification where pathway separation is generally not required TIA-1005-1 [B8] addresses 35 separation in industrial spaces with an E2 and E3 MICE classification However power circuit 36 types are not typical of a substation environmentrsquos CT and VT circuits 37

Co-installation of telecommunications cable and power cable is addressed by TIA-569-C [B5] 38 and the NEC [B144] where minimum separation requirements of electrically conductive 39 telecommunications cable from typical branch circuits requires 40

a) Separation from power conductors 41




b) Separation and barriers within raceways and 1

c) Separation within outlet boxes or compartments 2

Zero pathway separation distance can be utilized when the electrically conductive 3 telecommunications cables the power cables or both are enclosed in metallic pathways that 4 meet the following conditions 5

a) The metallic pathway(s) completely enclose the cables and are continuous 6

b) The metallic pathway(s) are properly bonded and grounded per TIA-607-B [B7] and 7

c) The walls of the pathway(s) have a minimum thickness 1 mm (004 in) nominal if 8

made of steel or 15 mm (006 in) nominal if made of aluminum 9

No separation is generally required between power and metallic telecommunications cables 10 crossing at right angles 11

In addition metallic communication cable should not be installed near fluorescent lights TIA-12 1005-1 [B8] requires metallic Ethernet cabling be separated from fluorescent lamps and 13 associated fixtures by a minimum of 5 in 14

Also see Annex H for more information on electrical segregation common to communication 15 cables regardless of type 16


55 Transient protection 18

551 High-speed data circuits 19

The following guidelines are provided for computer circuits and the circuits for high-speed 20 data logging applications using low level analog signals 21

a) The circuits should be made up of STP cables For noncomputer-type applications 22 such as annunciators shielding may not be required 23

b) Twisting and shielding requirements for both digital input and digital output signals 24 vary among different manufacturers of computerized measuring systems Separation 25 of digital input cables and digital output cables from each other and from power 26 cables may be required Where digital inputs originate in proximity to each other 27 twisted pair multiple conductor cables with overall shield should be used or multiple 28 conductor cable with common return may be permitted and overall shielding may not 29 be required Digital output cables of similar constructions may also be permitted 30 Individual twisted and shielded pairs should be considered for pulse-type circuits 31

c) Cable shields should be electrically continuous except when specific reasons dictate 32 otherwise When two lengths of shielded cable are connected together at a terminal 33 block an insulated point on the terminal block should be used for connecting the 34 shields 35




d) At the point of termination the shield should not be stripped back any further than 1 necessary from the terminal block 2

e) The shield should not be used as a signal conductor 3

f) Use of STP cable into balanced terminations greatly improves transient suppression 4

g) Use of a common line return both for a low-voltage signal and a power circuit should 5 not be allowed (Garton and Stolt [B33]) 6

h) Digital signal circuits should be grounded only at the power supply 7

i) The shields of all grounded junction thermocouple circuits and the shields of 8 thermocouple circuits intentionally grounded at the thermocouple should be grounded 9 at or near the thermocouple well 10

j) Multi-pair cables used with thermocouples should have twisted pairs with 11 individually insulated shields so that each shield may be maintained at the particular 12 thermocouple ground potential 13

k) Each resistance temperature detector (RTD) system consisting of one power supply 14 and one or more ungrounded RTDs should be grounded only at the power supply 15

l) Each grounded RTD should be on a separate ungrounded power supply except that 16 groups of RTDs embedded in the windings of transformers and rotating machines 17 should be grounded at the frame of the respective equipment as a safety precaution A 18 separate ungrounded power supply should be furnished for the group of RTDs 19 installed in each piece of equipment 20

m) When a signal circuit is grounded the low or negative voltage lead and the shield 21 should be grounded at the same point 22

552 Metallic cables 23

Metallic communication cable is vulnerable to transients that occur within a substation IEEE 24 Std 1615 [B104] recommends metallic cable only within the same panel in all circumstances 25 fiber or metallic cable between panels and fiber optic cable for cables leaving the control 26 building and terminating in the substation yard Communication ports can be protected against 27 transients when compliant to standards such as IEEE Std 1613 [B103] or IEC 61850-3 [B63] 28 but error-free communications before during and after the transient is only specified by IEEE 29 Std 1613 [B103] 30

Cable shielding using metal braid or Mylar film is an important requirement for telephone 31 cabling within a substation Crosstalk electromagnetic interference (EMI) and transient spikes 32 can seriously affect the transmission of digital signals The most effective method to provide a 33 low signal to noise ratio is to shield the individual pairs An overall shield limits exterior 34 interferences but will not protect against internal coupling and cross-talk In general 35 communications cable shields are grounded at one end to prevent ground loop potentials and 36 the associated noise In cases where equipment designs require grounds at both ends 37 capacitors can be used between the shield and ground to block dc voltages Isolation amplifiers 38 have also been employed 39




Isolation devices may be used to protect communication ports that are not rated for substation 1 transients per IEEE Std 1613 [B103] This can be accomplished using surge protection devices 2 that are commonly available for RS485 circuits or fiber optic transceivers that are commonly 3 available for RS232 RS485 and Ethernet ports 4

553 Isolation of telephone cables 5

In general the local telephone company provides or requires the electric utility to provide one 6 or more isolating devices in the substation When provided by the telephone company they 7 may lease and leases the protection interface including its maintenance to the electric utility 8 One or more of the following protection devices may be installed to protect against power-9 frequency GPR 10

Typically the following isolation equipment is used 11

a) Drainage unit (drainage reactormutual drainage reactor) is a center-tapped inductive 12 device designed to relieve conductor-to-conductor and conductor-to-ground voltage 13 stress by draining extraneous currents to ground 14

b) Isolating (insulating) transformers provide longitudinal (common mode) isolation for 15 the facility They can also be used in a combined isolating-drainage transformer 16 configuration 17

c) Neutralizing transformers introduce a voltage into a circuit pair to oppose an 18 unwanted voltage They neutralize extraneous longitudinal voltages resulting from 19 ground voltage rise or longitudinal induction or both while simultaneously allowing 20 ac or dc metallic signals to pass 21

d) Optical couplers (isolators) provide isolation using a short-length optical path 22

For additional information on these methods see IEEE Std 487 [B77] IEEE Std 4872 [B79] 23 IEEE Std 4873 [B80] and IEEE Std C3793 [B108] for cables carrying voice grade telephone 24 circuits and the most current version of IEEE Std 789 [B88] 25


The pull tension of the communication cable being installed should not be exceeded For 27 metallic Ethernet cable this is 110 N (25 lbf) per TIA-568-C [B10] There are no cable 28 specifications for RS232 and RS485 cables while USB cables are typically too short for 29 pulling and the USB standard does not include any specification for cable pulling tensions 30 For all cables always follow the vendor specifications on maximum cable pulling tension 31

TIA-569-C [B5] states that the following will impact cable pulling tension 32

a) Conduit size 33

b) Length of conduit 34

c) Location and severity of bends 35

d) Cable jacket material 36




e) Cable weight 1

f) Number of cables 2

g) Conduit material 3

h) Lubricants 4

i) Direction of pull 5

j) Firestopping 6

Conduit sizing is directly related to the planned diameter of the cable and the maximum pull 7 tension that can be applied to the cable without degradation of the cable transmission 8 properties It also depends upon whether the cable termination is pulled with the cable or not 9 The pull tension limit is based on the strength of the conduit (including sidewall pressure) the 10 tensile strength of the pull line the geometry of the conduit system and the tensile strength of 11 the cable The position of the bends and length of the conduit system will affect the pull 12 tension that will be imposed on a cable Pulling cables from different directions may result in 13 different pulling tensions Lubricants can be used to reduce pulling tensions but care should 14 be practiced in lubricant selection taking into consideration compatibility with cable jacket 15 composition safety lubricity adherence stability and drying speed 16

57 Handling 17

The conductors in communications cable are typically twisted pairs Cable performance will 18 degrade when the cable is improperly handled Cable stress such as that caused by tension in 19 suspended cable runs and tightly cinched bundles should be minimized Cable bindings if 20 used to tie multiple cables together should be irregularly spaced and should be loosely fitted 21 (easily moveable) The cable should not be subjected to pulling tension exceeding the pulling 22 strength rating of the cable The cable bend radius should be greater than or equal to the 23 minimum bend radius requirement during and after installation 24

See Annex K for common requirements for cable handling 25


In order to support the full speed and capability of communication cables it is essential that 27 the cables be installed with care to avoid kinks excessive pulling tension and exceeding the 28 minimum bend radius of the cable TIA-568-C [B10] provides cabling installation 29 requirements for Ethernet cabling 30

Communication cable installation should meet the requirements of the National Electrical 31 Safety Code (NESC) (Accredited Standards Committee C2) Although the National Electrical 32 Code (NEC) (NFPA 70) [B144] is not applicable to substations under the exclusive control of 33 electric utilities it provides valuable guidance 34

Probably the most common installation mistake is making tight bends in any communication 35 cable Tight bends kinks knots etc in communication cable can result in a loss of 36 performance The minimum bending radius should be considered by the engineer when 37 specifying the communication pathway 38




Specific coefficients of friction depend on cable jacket type conduit type and the lubricant 1

59 Acceptance testing 2

Note that Annex M is not applicable to communication cables This clause covers test 3 procedures for metallic communication cables 4


Communication cable performance is dependent upon the quality of the terminations Unlike 6 power and control cable the number of connectors available can vary greatly for 7 communication cables Ethernet cables should be terminated per TIA-569-C [B5] Termination 8 of other communications cables are generally not governed by standards Proper termination is 9 usually confirmed by monitoring the communication channel for errors and finding no errors 10 over an extended period of time such as days or weeks after termination 11

Many Ethernet cables in substations should be tested to meet TIA-1005-A [B8] which is for 12 telecommunications cabling in industrial premises This standard provides additional 13 requirements to the tests in TIA-568-C2 [B4] However this only covers Category 3 5e 6 14 and 6A and there are a variety of ldquoEthernet cablesrdquo so acceptance testing may be specified by 15 any of the following 16

Category 3 5e 6 and 6A per ANSITIA-568-C2 [B4] 17

Category 5 (1000BaseT) per TIA TSB-95 [B9] 18

Category 6 per TIAEIA-568B2-1 [B10] 19

TIA TSB-155-A [B12] (for installed Category 6 cable to support 10GBaseT) 20

ISO TR 24750 [B117] (for installed channels to support 10GBaseT) 21

ISOIEC 11801 [B115] (for Category 1 2 3 5e 6 6A 7 and 7A in general purpose 22

cabling systems) 23

EN 50173 as the European equivalent to ISOIEC 11801 [B115] 24

IEEE 8023 [B89] 10BASE-T 100BASE-TX 1000BASE-T 25

IEEE 8023an [B90] 10GBASE-T 26

For all other Ethernet cables follow the manufacturerrsquos recommendations 27

592 USB cables 28

USB cables are tested to the USB specification but can be tested by third parties using the 29 ldquoCables and Connectors Class Documentrdquo available from the USB website 30





For power line carrier based systems using coaxial cable see IEEE Std 643-2004 clause 2 10122 [B87] for installation testing procedures 3

594 Other cables 4

Because of the low voltage requirements of non-Ethernet communication systems a continuity 5 check for all conductors is all that is typically required but this can be difficult when the cable 6 connectors are not located near each other In addition continuity does not mean that a 7 communications cable will function properly There can be additional issues causing the 8 problem such as improper 9

a) Cable shield connections 10

b) Cable ground connections 11

c) Signal wire connections 12

d) Connector installation 13

e) Cable selection 14

f) Cable capacitance 15

g) Termination (RS485 and IRIG-B typically exhibit these problems) 16

h) Power to connected devices andor port-powered converters 17

i) Application layer protocol configuration (ie Modbus IEEE 1815 [B105] (DNP3) etc) 18

This is typically why these cables are only checked when there is a communication problem 19


6 Fiber-optic cable 21

This clause covers the following for fiber optic communication cables within and to 22 substations 23

1) General information regarding fiber optic cable types 24

2) Fiber types 25

3) Cable construction 26

4) Overall jackets 27

5) Terminations 28








10) Cable pulling 2

11) Handling 3

12) Installation 4



61 General 7

Fiber optic cables are commonly used inside the substation fence because a substation 8 typically has an electrically noisy environment (see IEEE Std 1613 [B103] and IEEE Std 1615 9 [B104]) Fiber optic cables rely on the principle of the total internal reflection of light This 10 means that fiber optic cables ldquoconductrdquo light (infrared or visible) over distances that depend 11 upon the cable construction installation and transmitter strength and receiver sensitivity 12

Inside the substation fence fiber optic cable is commonly used to connect together substation 13 IEDs instrumentation such as optical CTs and VTs and communication devices These 14 devices are commonly located in the control building or somewhere within the substation yard 15 typically in yard equipment cabinets Fiber optic cables are typically used in point-to-point 16 links however one point may be a passive or active and allow the creation of multipoint fiber 17 optic loops It is not recommended that metallic armored fiber optic cable be installed when 18 the entire cable is within a substation See clause 644 19

Fiber optic cables are also used to connect the substation IEDs to other equipment located 20 outside the substation transporting communications between protective relays for protective 21 relay applications between substations and interconnecting simple to large substation networks 22 to utility enterprise and operational networks Refer to IEEE Standard Std 4872 [B79] and 23 IEEE Std 4873 [B80] as reference for fiber optic cable entering a substation and crossing the 24 zone of influence (ZOI) 25

All fiber cables have the same basic components that vary with the type of fiber core and cable 26 construction as shown in Figure 4 27

a) Core The core is transparent to light and is typically made from glass or plastic 28

b) Cladding The cladding consists of an optical material on the layer outside the core 29

that reflects or bends the light back into the core Cladding is typically 125 μm thick 30

c) Buffer The buffer can be made of multiple layers that do not carry light The buffer 31

protects the inner layers from moisture and damage where moisture inhibits the 32

performance of the core The buffer also includes strength members typically made of 33

aramid yarn to prevent the fiber from breaking 34

d) Jacket The jacket provides the outermost layer or layers of protection for the fibers 35

The jacket materials depend on the application and serves as mechanical protection to 36

the fiber core and cladding inside Metallic and non-metallic armoring can be 37




considered part of the cable jacket Common types of fiber optic cable jackets with and 1

without armoring are discussed in clause 64 2 3

Cable color and fiber colors have color codes per TIA-598-C [B6] when containing a single 4 type of fiber 5

6 Figure 4 mdashTypical fiber cable construction 7

62 Fiber types 8

Three types of optical fibers find common usage singlemode glass multimode glass and 9 plastic Comparisons between cabled versions of glass fiber are shown in Table 4 based upon 10 amendment 2 of IEC 11801 [B115] (for glass fiber) with TIA and IEC cross references 11 Distances shown are typical 12

Table 4 mdashFiber type characteristics 13

Specification Multimode Singlemode Plastic OM1 OM2 OM3 OM4 OS1 OS2

ITU-T NA NA G6511 G6511 G6511 G652 Table 2

G655C G655D

TIA NA 492AAAA 492AAAB 492AAAC-B 492AAAD 492CAAA 492CAAB IEC 60793-2-10 Type (MM) IEC 60793-2-50 Type (SM)

NA A1b A1a1 Type A1a2 Type A1a3

B13 B4C B4D

Core μm NA 625 50 50 50 9 9 Cladding μm NA 125 125 125 125 125 125 Laser Optimized NA No No Yes Yes No No Wavelength of transmitted light nm

NA 850 1300

850 1300

850 1300

850 1300

1310 1550

1310 1383 1550

Maximum attenuation dBkm

NA 3515 3515 3515 3515 10 04

Minimum modal bandwidth-length for overfilled launch at 850 nm (MHzmiddotkm)

NA 200 500 1500 3500 NA NA

Minimum modal bandwidth-length

NA 500 500 500 500 NA NA




for overfilled launch at 1300 nm (MHzmiddotkm) Minimum effective modal bandwidth-length at 850 nm (MHzmiddotkm)

NA Not specified

Not specified

2000 4700 NA NA

100 MB Ethernet channel distance m

NA 2000 2000 2000 2000 2000 2000

1 GB Ethernet channel distance m

NA 275 550 550 1000 2000 2000


NA 33 82 300 550 2000 2000


NA Not supported

Not supported

100 150 2000 2000


NA Not supported

Not supported

100 150 2000 2000

1

Other types of fiber exist that are not in Table 4 Plastic fibers are not shown because there are 2 no standards for plastic fiber optic cables Bend-insensitive fiber has been introduced for 3 singlemode (BISMF) and multimode fiber (BIMMF) Bend insensitive fiber is of interest when 4 tight bends can not be avoided in the cable installation Any bend insensitive fiber only 5 addresses the optical performance at tight bends and does not change the fiberrsquos other 6 capabilities Bend insensitive fibers are generally available in OM2 OM3 and OM4 7 multimode versions and singlemode versions Some manufacturers have decided to make all 8 multimode fiber as bend-insensitive fiber Care should be used when testing bend insensitive 9 fibers and when installing both normal and bend insensitive fiber It is still being argued within 10 industry whether or not interoperability exists between standard and bend-insensitive fibers 11 Standards for BIMMF and BISMF are 12

a) ITU-T G657 [B120] provides two categories of single mode fiber 13

1) Category A fiber that is ITU-T G652 [B119] compliant 14

i) A1 provides a minimum 10 mm bending radius 15

ii) A2 provides a minimum 75 mm bending radius 16

2) Category B fiber that is not ITU-T G652 [B119] compliant 17

i) B2 provides a minimum 75 mm bending radius 18

ii) B3 provides a minimum 5 mm bending radius 19

b) IEC 60793-2-10 [B58] for multimode fiber provides a 375 mm bending radius 20

c) ITU-T G6511 [B118] for multimode fiber provides a 15 mm bending radius 21

Table 5 compares the different fiber alternatives 22

Table 5 mdashComparison of fiber types 23

Consideration Singlemode fiber Multimode fiber Plastic fiber (HCS) Distance Longest Moderate Shortest Cost Moderate Moderate Lowest Use Inter-substation fiber Intra-substation fiber

Moderate distances to Intra-substation fiber of short length




outside substation

1

621 Singlemode fiber 2

Singlemode glass fiber has a fiber core diameter of about 9 microm which is much closer in size to 3 the wavelength of light being propagated about 1 microm The result is that only a light ray at a 0deg 4 incident angle can pass through the length of fiber without much loss The core is small 5 enough to restrict transmission to a singlemode This singlemode propagation happens in all 6 fibers with smaller cores when light can physically enter the fiber The mode depends on the 7 wavelength of the light used as calculated by EIATIA-455-191 (FOTP-191) [B23] 8 Singlemode fiber typically has a core diameter of 8 to 10 μm and uses near infrared 9 wavelengths of 1310 nm and 1550 nm Because of a singlemode of light transmission the 10 number of light reflections created as the light passes through the core decreases lowering 11 attenuation and creating the ability for the signal to travel faster and farther than multimode 12

Because of the small core singlemode fiber transmitters require very precisely mounted lasers 13 and the receivers require very precisely-mounted photodiodes The cost of the laser and 14 associated driver circuitry contributes to the cost of fiber links Singlemode is typically used 15 for high data rates or between substations where distances are longer than a few kilometers 16

Cable performance classifications of singlemode fiber are unclear 17

OS1 is dispersion-unshifted singlemode fiber that has a nominal zero-dispersion 18 wavelength at 1310 nm OS1 is appropriate to internal tight buffered cable 19 construction OS1 is an old specification for singlemode fiber traceable to ISOIEC 20 11801 [B115] published in 1995 The term OS1 was introduced around 2002 OS1 is a 21 general term used to specify singlemode optical fibers that comes under the heading of 22 ITU-T G652 23

OS2 is dispersion-unshifted singlemode fiber that has a nominal zero-dispersion 24 wavelength in the 1310 nm transmission window The origins of OS2 fiber are in the 25 industrial premises standard ISOIEC 24702 [B116] and OS2 was introduced in 2006 26 These fibers are characterized by having a low environmentally stable attenuation 27 coefficient in the vicinity of 1383 nm which is traditionally referred to as the ldquowater 28 peakrdquo The low attenuation values of OS2 fiber are typically only realistic in loose 29 tube cables or blown fiber where the original optical fiber is almost unaltered by the 30 cabling process 31

There may be a problem of interoperability between OS1 and OS2 fibers because an OS1 32 cable is not simply an indoor version of an OS2 cable When using the OS1OS2 performance 33 specifications make sure they are for the constructed cables and not just the optical fibers 34 contained within them 35

622 Multimode fiber 36

Multimode fiber has a core diameter that is relatively large compared to a wavelength of light 37 50 to 1000 microm compared to lightrsquos wavelength of about 1 microm Light can propagate through 38 the fiber in many different ray paths or modes for this reason the name is multimode There 39 are two types of multimode fibers the simpler and older step-index multimode and graded-40 index 41




Step-index fiber has same index of refraction (the ability of a material to bend light) all across 1 the core Modal dispersion causes pulses to spread out as they travel along the fiber the more 2 modes the fiber transmits the more pulses spread out Different rays travel different distances 3 taking different amounts of time to transit the fiberrsquos length When a short pulse of light is 4 transmitted the various rays emanating from that pulse arrive at the other end of the fiber at 5 different times and the output pulse will be longer in duration than the input pulse This is 6 called modal dispersion or pulse spreading which limits the number of pulses per second that 7 can be transmitted down a fiber and still be recognizable as separate pulses at the other end 8 This limits the bit rate or bandwidth of a multimode fiber A typical step-index multimode 9 fiber with a 50 microm core is limited to approximately 20 MHz for one kilometer or a bandwidth 10 of 20 MHzbullkm 11

Graded index multimode fiber has a gradual change in the index of refraction across the core 12 from a maximum at the center to a minimum near the edges This design leverages the 13 phenomenon of light traveling faster in a low-index-of-refraction material than in a high-index 14 material The graded index allows light rays that travel near the edges of the core travel faster 15 for a longer distance thereby transiting the fiber in approximately the same time as other rays 16 traveling more slowly near the center of the core A typical graded-index fiber may have 17 bandwidth between 200 MHzbullkm and 3 GHzbullkm Subsequently multimode fiber allows high 18 data rates at long distances (for example 100 Mbps at approximately 2000 m) Multimode 19 fiber transmitters typically use precision-mounted LEDs and the receivers use precision-20 mounted photo-diodes The main limitation of the media is the optical pulse dispersion which 21 is predominant at high data rates and long distances 22

High performance multimode fibers are also available for use with gigabit Ethernet networks 23 utilizing laser light sources Laser optimized cables are specifically designed for these 24 networks because of the smaller optical budget limits or link loss budgets By optimizing the 25 link loss of the cable longer cable runs are possible However multi-mode fiber is usually 26 confined to intra-substation applications due to distance limitations 27

The OM designations are to specify the cabled performance of the fiber and are as follows 28

OM1 is a legacy grade fiber originally was designed for use with 1300 nm LEDs that 29 operate at speeds of 100 Mbps 30

OM2 fiber enables extension of legacy 50 μm MMF cabling and is typically used for 31 entry-level 1 Gb speed performance 32

OM3 laser-optimized fiber is the minimum recommended performance level for new 33 installations today OM3 is fully compatible with legacy OM2 installations 34

OM4 is a laser-optimized fiber that further extends the capabilities of OM3 and is 35 fully compatible with legacy OM3 and OM2 installations OM4 is recommended when 36 OM3 distance ranges are exceeded or it is anticipated they will be exceeded in the 37 future 38

Using two different types of fiber in the same run should be avoided because it can cause 39 severe losses Connecting a 50125 multimode fiber to a 625125 multimode fiber results in 40 easy coupling of the smaller core of the 50125 to the 625125 fiber and is very insensitive to 41 offset and angular misalignment However the larger core of 625125 fiber overfills the core 42 of the 50125 fiber creating excess loss 43

623 Plastic fiber 44

Plastic fiber optic cable as a general term can be organized into the following types of 45 multimode cables 46




a) hard-clad silica (HCS) 1

b) polymer-clad fiber (PCF) 2

c) hard plasticpolymer clad silica (HPCS) 3

d) plastic clad silica (PCS) 4

These plastic cables have a glass core and plastic cladding These typically have a step index 5 profile and exhibit a limited bandwidth of approximately 20 MHzbullkm to 30 MHzbullkm The 6 most successful implementation is HCS of a 200 microm or 230 microm size 7

There is also polymerplastic optical fiber (POF) that is made out of plastic with the core 8 material as polymethylmethacrylate (PMMA) and fluorinated polymers used for the cladding 9 material POF could also be based on perfluorinated polymers (mainly 10 polyperfluorobutenylvinylether) that offer greater bandwidth performance POF is transparent 11 to light within the visible spectrum from 400-780 nm where the most commonly used LEDs 12 and photodiodes work with red light at 650 nm The POF core size can be up to 100 times 13 larger than the core of glass fiber 14

Plastic fiber losses are extremely high but the material is very inexpensive Plastic fiber 15 selection can be driven by very low-cost LEDs and detected by inexpensive photo-transistors 16 but the fiber can only be used over shorter distances that are also very typical in substation 17 applications However there are no available applicable standards for plastic fiber 18

POF and HCS characteristics make it more suited for some applications over traditional glass 19 fiber such as applications that require 20

very tight bend radius where these products may have a bend radius as low as 20-21 25 mm without excessive attenuation 22

visual troubleshooting where the assemblies transmit the signal using visible light 23 making the user aware of its attachment to an active laser and helping to increase 24 the awareness of possible associated dangers 25

wide tolerance for scratching and contamination (when using higher frequencies) 26 that allows performance at an acceptable level despite some compromise in 27 physical condition 28

resistance to an environment that includes strong vibration 29

POF is typically used for illumination and medical applications where communications is 30 a specialty application and there are no standards for this POF as there are for multimode 31 and singlemode fibers Care should be used when using POF from different vendors to 32 confirm they are compatible 33


There are a wide variety of fiber optic cable constructions using the fiber types discussed in the 35 previous clause In addition to choices of fiber type the number of fibers can range from two 36 to hundreds 37

In addition there is an internal dielectric tension member aramid strength member a duct that 38 is integral with the cable and armor The cable diameter is a function of the construction and 39 ranges from 4 mm to more than 20 mm Additional information about available cable 40




constructions is available from various manufacturers Cable types are loose tube tight buffer 1 and ribbon types 2

625 Loose tube cables 3

Loose tube cables are composed of several fibers inside a small plastic tube each tube is 4 wound around a central strength member surrounded by aramid strength members and 5 jacketed 6

The buffer tubes are color-coded A gel filling compound or water absorbent powder impedes 7 water penetration through the loose tube and the fiber can freely move within the tube This 8 construction provides a small high fiber count cable This provides less strain and the fiber 9 expands and contracts with changes in temperature Loose tube fiber can be used in conduits 10 strung overhead or buried directly into the ground In addition the fibers have better bending 11 performances as the fiber inside can wander inside the loose tube cable Loose tube cables can 12 be stretched more during installation without stressing the optical fiber Loose tube cables are 13 most widely used in outside plant applications because it offers the best protection for the 14 fibers under high pulling tensions and can be easily protected from moisture with water-15 blocking gel or tapes Some outdoor cables may have double jackets with a metallic armor 16 between them to protect from chewing by rodents or kevlar for strength to allow pulling by the 17 jackets Loose tube fibers can be constructed into cables that are armored all-dielectric self-18 supporting (ADSS) or optical ground wire (OPGW) 19

626 Tight buffered cables 20

Tight buffered cables have the buffering material in direct contact with the fiber which tightly 21 wraps around the optical fiber This provides a rugged cable structure for better mechanical 22 protection of fibers during handling and installation The strength members are placed either 23 after the outer cable jacket or around each individual fiber optic jacket which is often referred 24 to as sub-jackets 25

Tight buffer cables are typically used when cable flexibility and ease of termination are 26 important with the following types 27

Simplex and zipcord are used mostly for patch cord or jumper applications where the 28 fiber is installed between patch panels between end devices or between end devices 29 and patch panels Simplex cables are one fiber tight-buffered (coated with a 900 30 micron buffer over the primary buffer coating) with aramid fiber strength members 31 and jacketed The jacket is usually 3mm (18 in) diameter Zipcord is simply two of 32 these joined with a thin web Simplex and zipcord cable constructions may allow for 33 indoor andor outdoor installations 34

35 Distribution cable is a very popular indoor cable because it is small in size and light in 36

weight They typically contain several tight-buffered fibers bundled under the same 37 jacket with aramid strength members and sometimes fiberglass rod reinforcement to 38 stiffen the cable and prevent kinking These cables are used for short dry conduit runs 39 riser and plenum applications The fibers are typically double buffered and can be 40 directly terminated but because their fibers are not individually reinforced these 41 cables need to be broken out or terminated inside a patch panel or junction box to 42 protect individual fibers 43

44




Breakout cable is very popular for rugged applications for direct termination without 1 patch panels Breakout cables consist of several simplex cables bundled together 2 inside a common jacket This provides a strong rugged design however the cable is 3 larger and more expensive than distribution cables Breakout cable is suitable for 4 conduit runs riser and plenum applications Breakout cable can be more economic in 5 some situations because there they require much less labor to terminate 6

627 Ribbon cables 7

Ribbon cable is preferred where high fiber counts and small diameter cables are needed 8 Ribbon cable has the most fibers in the smallest cable because all the fibers are laid out in rows 9 in ribbons and the ribbons are laid on top of each other Ribbon cable may be available at 10 lower cost and 144 fibers may have only a cross section of about 32 mm 6 mm for the fiber 11 and 13 mm for the jacket Ribbon cable is outside plant cable and can be filled with gel or 12 water absorbent powder to help prevent harm to the fibers from water 13

628 Overall jackets 14

This includes temperature sunlight and exposure to water 15

Some available constructions include cables designed for the following 16

a) Indoor (plenum and riser) 17

b) Outdoor including 18

1) OPGW (see IEEE Std 1138 [B95]) 19

2) all-dielectric self-supporting (ADSS) (see IEEE Std 1222 [B99]) 20

3) wrapped (see IEEE Std 1594 [B102]) 21

4) direct-bury armored 22

c) Multi-use or indooroutdoor 23

629 Indoor cable jackets 24

Indoor cables use flame-retardant jackets cables may have double jackets with metallic or non-25 metallic armor between them to protect from chewing by rodents or aramid for strength 26 allowing the jacket to be pulled Indoor-outdoor cables have a PE outer jacket that can be 27 removed to expose a flame-retardant inner jacket for use within buildings 28

The overall jacket should be suitable for the conditions in which the fiber optic cable will be 29 installed The NEC 2011 [B144] designates the following indoor fiber optic cables 30

Optical Fiber Nonconductive Plenum (OFNP) cables have fire-resistance and low 31 smoke production characteristics They can be installed in ducts plenums and other 32 spaces used for building airflow This is the highest fire rating fiber cable and no other 33 cable types can be used as substitutes 34

Optical Fiber Conductive Plenum (OFCP) cables have the same fire and smoking 35 rating as OFNP cables but they have a conducting armor or central strength member 36 which is usually steel OFCP cables should be properly grounded at both ends As a 37




result OFCP cables can not be installed in the same cable tray or conduit as power 1 cables 2

Optical Fiber Nonconductive Riser (OFNR) cables are used in riser areas that are 3 building vertical shafts or runs from one floor to another floor OFNR cables can not 4 be installed in plenum areas since they do not have the required fire and smoking 5 rating as plenum cables 6

Optical Fiber Conductive Riser (OFCR) cables have the same fire rating 7 characteristics as OFNR cables but they have conducting armor or central strength 8 member such as steel OFCR cables should be properly grounded at both ends OFCR 9 cables can not be installed in the same cable trays or conduits as power cables 10

Optical Fiber Nonconductive General-Purpose (OFNG) cables are typically used in 11 horizontal cabling single floor applications OFNG cables can not be used in plenums 12 or risers 13

Optical Fiber Conductive General-Purpose (OFCG) cables have the same fire 14 characteristics as OFNG cables but they have conducting armor or central strength 15 members such as steel OFCG cables should be properly grounded at both ends They 16 should not be installed in the same cable tray or conduits as power cables 17

Nonconductive optical fiber general-purpose cable (OFN) 18

Conductive optical fiber general-purpose cable (OFC) Some fiber optic installations may 19 require extra protection for the cable due to an installation environment with congested 20 pathways damage due to rodents construction work weight of other cables and other factors 21 Both metallic and dielectric armored options exist Inside a substation control building or other 22 building use of indoor rated cables with metallic armor is avoided For discussion of armor 23 see clause 642 24

When jacket coloring is used for indoor cable the following are the typical jacket colors for 25 indoor cable of a single fiber type for non-military applications per TIA-598-C [B6] 26

Yellow ndash singlemode optical fiber (TIA-492C000TIA-492E000) 27 Orange ndash multimode optical fiber (50125 TIA-492AAAB 625125 TIA-492AAAA 28

100140) 29 Aqua ndash Laser optimized 50125 micrometer multi-mode optical fiber (TIA-492AAAC) 30 Grey ndash outdated color code for multimode optical fiber 31 Blue ndash polarization-maintaining fiber 32

Other jacket colors may be used as long as they are agreed to by the user and manufacturer 33

The cable can also be installed in a colored conduit (or innerduct) in lieu of the jacket coloring 34 to better differentiate the cable from the other substation cables 35

6210 Outdoor cable jackets 36

Outdoor rated cable requires protecting the fibers from the environment especially water 37 Either a gel or absorbent tape or powder is used to prevent water from entering the cable and 38 causing harm to the fibers Generally this applies to loose tube or ribbon cables but dry water-39 blocking is used on some tight buffer cables used in short outdoor runs Outside cables 40 generally have black polyethelene (PE) jackets that resist moisture and sunlight exposure 41 sometimes these jackets are color-coded like indoor cable when they indooroutdoor rated 42 The cable can also be installed in a colored conduit (or innerduct) in lieu of the jacket coloring 43 to better differentiate the cable from the other substation cables 44




Some outdoor cables may have double jackets with metallic or non-metallic armor between 1 them to protect from chewing by rodents or aramid for strength allowing the jacket to be 2 pulled Indoor-outdoor cables have a PE outer jacket that can be removed to expose a flame-3 retardant inner jacket for use within buildings 4

Fiber optic cable installed in underground applications may have an armored jacket Armored 5 fiber optic cables are often installed for added mechanical protection Two types of metallic 6 armor exist 7

Interlocked armor is an aluminum armor that is helically wrapped around the cable and 8 found in indoor and indooroutdoor cables It offers ruggedness and superior crush 9 resistance 10

Corrugated armor is a coated steel tape folded around the cable longitudinally It is 11 found in outdoor cables and offers extra mechanical and rodent protection 12

Use of metallic armoring in fiber cables should be avoided in substations and power plants 13 The use of metallic armoring for fiber cables is a carryover from the phone companies that 14 were not familiar with installations with substantial ground potential rise Metallic armored 15 cable is terminated outside the substation to transition to another fiber cable type that is more 16 appropriate for installation in a substation See IEEE Std 4872 [B79] 17

OPGW is not considered metallic armored cable but when used should not be used for 18 building entrance Even with the best grounding practices it is possible for a severe ground 19 potential rise to vaporize a section of the fiber cable and damage other cables andor 20 equipment or personnel in its proximity Typically OPGW cable is terminated in an outdoor 21 cable enclosure where it is spliced to another cable type more suitable for building entrance 22

Dielectric-armored cable options exist offering the protection of armor without the 23 requirement for grounding and bonding the armor and without the need for a conduit 24 Dielectric armored fiber-optic cable (also called metal-free armored rodent resistant or 25 dielectric conduited) eliminates the need for accessing and grounding a typical armored cable 26 Cable is available for use as indoor (riser plenum and general purpose) and outdoor cable that 27 is direct-buried or installed in ducts All-dielectric armor can offer more than four or six times 28 the crush protection (ICEA S-83-596 [B46] test criteria) or a crush rating of approximately 6 29 N-m (or around 52 in-lbs) compared to unarmored cables The cable typically provides 30 increased tensile strength when cables require high pulling tensions There are no metallic 31 components within the all-dielectric armor reducing installation time and expense by 32 eliminating the need to ground the cable and simplifying access to the fiber 33

Dielectric-armored cable is particularly useful in fiber runs with challenging mechanical 34 exposure conditions high pulling tensions pronounced rodent infestation and where armored 35 cable would be normally required where other means of protection would be needed to protect 36 the fiber cable tight areas where only a single cable tray is available for power and fiber or 37 other installations where cable tray is not available and J-hook installation is used 38

With J-hook installations under normal load conditions standard non-armored fiber optic 39 cables may sag between the J-hooks due to the normal weight of the cabling solution TIA-569 40 [B5] specifies a maximum J-hook installation between four and five feet If the cable is heavy 41 enough it is possible to pinch the fibers located at the bottom of the cable in contact with the 42 J-hook and cause increased signal loss Dielectric-armored fiber will not sag as much and all 43 of the weight is placed upon the armor 44

Cable tray installations may be used to provide a single pathway for different cables or it may 45 be required because there is no room for a separate cable tray When fiber optic cable is placed 46




in a cable tray with large amounts of other cable the fiber cable should be placed on top of the 1 cable bundles to prevent crushing or large downward pressure causing high attenuation in the 2 cable Unfortunately keeping this fiber on top of all the other cable is difficult to guarantee 3 over the life of the cabling installation Dielectric-armored cable provides improved crush 4 resistances that prevent degradation in fiber performance due to micro-bends in the fiber 5 strands 6

6211 Terminations 7

Loose tube cables with singlemode fibers are generally terminated by splicing pigtails onto the 8 fibers and protecting them in a splice enclosure Multimode loose tube cables can be 9 terminated directly by installing a breakout kit or fan-out kit which sleeves each fiber for 10 protection In each case the fibers are ultimately terminated with connectors 11

There are hundreds of fiber optic connectors that can be used to terminate fiber optic cables 12 The ones in common use are shown in the Table 6 Multimode connectors typically follow the 13 cable color code Singlemode connectors are blue when angle-polished singlemode are green 14 Outlets are also similarly color coded In most cases the choice of a devicersquos fiber termination 15 is done by a vendor who may provide no or limited options The introduction of the SFP 16 (small form-factor pluggable) transceivers allows the user to install the transceiver appropriate 17 for each application (fiber type and distance) SFP transceivers may usually use the LC 18 connector but in some instances different connector types may be available to provide the 19 desired connector type 20

Table 6 mdashFiber optic cable connectors 21

Acronym Name Standard Description SM MM POF Ferrule

mm ST 1 Stab and

Twist 2 Straight Tip 3 Square Tip

1 IEC 61754-2

2 FOCIS 2 EIATIA-604-2

The most common connector used in substations that features an individual bayonet locking system for each fiber Similar in appearance to a BNC connector

Rare X 25

SC 1 Square Connector

2 Stick and Click

3 Subscriber Connector

4 Standard Connector

1 IEC 61754-4

2 TIA-568-A


Contains housing for both fibers and has a push-pull locking mechanism Snaps into place Can be a single ferrule or duplex Replaced by LC connector

25

MT-RJ 1 Mechanical Transfer Registered Jack

2 Media Termination Recommended Jack

1 IEC 61754-18


Uses a latch mechanism similar to the 8P8C connector There are male and female connectors Only allows removal of both fibers

X 245times44 mm

LC 1 Little Connector

2 Lucent Connector

1 IEC 61754-20

2 FOCIS

Allows independent removal of the fibers Snaps into place Used for high density applications

X X 125




3 Local Connector

10 EIATIA-604-10

Commonly found on small form pluggable (SFP) transceivers Replaced the SC connector

FC 1 Ferrule Connector

2 Fiber Channel

3 Face Contact

1 IEC 61754-13

2 FOCIS EIATIA-604-4

A legacy competitor to the ST with better performance for single-mode fiber Have been replaced by SC and LC connectors Used for high density installations

X 25

SMA 1 Sub Miniature A

Screws into place Considered obsolete

X X Varies

VPIN Snaps into place with push-pull coupling Used in industrial and electrical utility applications

X 22

1

V-pin (VPIN) Versatile Link and VersaLink and are all names given to the proprietary fiber 2 optic connector originally developed by Hewlett-Packard which is now owned by Avago 3 These are connectors are not typically used on singlemode and multimode fiber cables 4

Single-mode fiber typically uses FC or ST connectors expect LC on high bandwidth 5 equipment Multimode fiber typically uses ST connectors expect LC on high-bandwidth 6 products (Ethernet) equipment 7


The service conditions listed in fiber optic cable specifications likely differ from the service 9 conditions experienced in substations See Annex B for the general discussion of the 10 mechanical ingress climatic or electromagnetic (MICE) characteristics IEC TR 62362 [B64] 11 offers additional guidance on the selection of optical fiber cable specifications relative to 12 MICE 13

Mapping the MICE characteristics onto existing fiber optic cable standards will likely change 14 the cable construction so the cable can perform within the required environment Fiber optic 15 cables are typically classified as outside plant (OSP) or inside plant Environmental 16 requirements are specified in several fiber optic cable standards where operating temperature 17 is a typical concern in substations Telcordia GR-20 and ICEA S-87-640 contain reliability 18 and quality criteria to protect optical fiber in all operating conditions installed as outside plant 19 Outdoor cable standard ANSIICEA S-87-640 defines very low temperatures as -50 degC with 20 normal operation of -40 to 70 degC 21

For indoor plant Telcordia GR-409 and ICEA S-83-596 [B46] define the environmental 22 requirements ICEA S-83-596 defines normal operating temperature ranges for different types 23 of indoor cable 0 to 70 degC for backbone horizontal and all interconnect cables -20 to 70 degC 24 for riser and general purpose vertical backbone and 0 to 70 degC for vertical plenum The 2011 25 NEC Article 770179 [B144] requires all indoor optical fiber cables have a temperature rating 26 of not less than 60 degC (140 degF) The TIA standards for multimode and singlemode fiber also 27 contain temperature performance requirements over the range of -60 to 85 degC 28




For OPGW IEEE Std 1138 [B95] references TIAEIA-455-3 for a temperature range of at 1 least ndash40 ordmC to at least 85 ordmC For ADSS IEEE Std 1222 [B99] references a temperature range 2 of ndash40 ordmC to 65 ordmC For wrapped fiber IEEE Std 1594 [B102] references TIAEIA 455-3A for 3 a maximum temperature range of ndash40 ordmC to 85 ordmC These standards also include other 4 environmental requirements and tests for these types of cables 5

In addition to the service conditions for the cable service conditions for the optical connectors 6 are also important The IEC 61754 series and the TIA-604 series have no temperature 7 requirements for fiber optic connectors Annex A of TIA-568-C3 [B10] requires fiber optic 8 connectors perform from -10 degC to 60 degC using TIA-455-4 (FOTP-4) and TIA-455-188 9 (FOTP-188) The referenced TIA-455 standards actually allow wider temperature ranges from 10 -65 degC to 500 degC Connectors and cable used in the same environment should be rated for the 11 same temperature range 12

64 Cable selection 13

Each fiber optic cable is typically specified with the following information for proper 14 application Before starting the selection process determine the options available in the end 15 devices for each fiber run including fiber type connectors wavelength and bandwidth These 16 will likely impact the selection of fiber cables to be used as designated by 17

a) Fiber type 18

b) Buffer tube configuration 19

c) Number of total fibers 20

d) Cable jacket 21

e) Terminations 22

641 Fiber type 23

Selecting the proper fiber type (plastic multimode singlemode) typically follows the 24 following steps 25

a) Calculate the distance involved (route) 26 b) Determine the required bandwidth 27 c) Determine the attenuation requirements 28

If possible consideration should be given to using the same type of fiber and wavelength and 29 mode-type throughout the substation This will minimize the number of converters needed 30 but it is likely that all three fibertypes are required for different applications 31

Fiber type selection results in the specification of the following 32

a) Fiber type glass that can be single mode or multimode or plastic with the following 33

specifications 34

1) Corecladding diameter 35




i) Singlemode 9125 μm 1

ii) Multimode 50125 or 625125 μm 2

2) Fiber performance designation (including attenuationloss performance) as listed 3

in the table above 4

i) OM1 OM2 OM3 and OM4 for multimode 5

ii) OS1 and OS2 for singlemode 6

3) Wavelength of transmitted light 7

i) Singlemode is typically 1310 or 1550 nm 8

ii) Multimode is typically 850 or 1300 nm 9

642 Buffer tube configurations 10

Loose or tight 11

643 Total number of fibers and tubes 12

Cables with more than two fibers (ie patch cables) require selecting the total number of 13 fibers and the number of tubes and the number of fibers per tube requires color coding per TIA 14 598-C [B6] Total fiber cable capacity and the number of fibers per tube both typically contain 15 even number of fiber counts based upon powers of two 2 4 8 16 32 64 etc This is not 16 always the case and no standard exists for how many fiber strands are allowed per tube andor 17 per cable 18

When fiber cables are terminated on each end by patch panels the total number of fibers and 19 fibers per tube should be matched with the patch panel capacity so that any one fiber cable is 20 not terminated across different patch panels 21

Consideration should be given in the final fiber count to provide adequate spare capacity 22 Spare capacity provides for the failure of individual strands which can be replaced by using an 23 available spare strand But this may also increase the number of supporting equipment (patch 24 panels splice trays enclosure size etc) that will increase installation and maintenance costs 25

644 Cable jacket 26

Select the cable jacket characteristics required for the application These are typically based 27 upon the following 28

1) Environmental considerations such as temperature 29 2) Bend requirements 30 3) Installation requirements such as low installation andor operating temperature 31 4) Armoring For safety considerations the use of non-metallic armoring is 32

recommended over metallic armor 33 5) Other 34

Cable jacket selection depends upon the installation location such as indoor outdoor or 35 indooroutdoor See IEC TR 62362 [B64] for guidance on the selection of optical fiber cable 36




specifications relative to mechanical strength ingress of moisture climatic or electromagnetic 1 characteristics See Annex B for the applicable characteristics for a substation 2

Plastic fiber cables are typically the most inexpensive cables and connectors but are distance 3 limited that may or may not impact their selection in the substation Multi-mode cables are 4 less expensive to install less efficient than single-mode cables and are used for shorter runs 5 within substations and outside substations The termination devices are less expensive than for 6 single-mode Regardless of fiber the transmission distance is impacted by the optical loss of 7 the cable the insertion loss of any splices or connectors the reflection loss of any splices or 8 connectors and the transmitter power and receiver sensitivity 9


Because fiber optic cables typically have many strands of fiber in them they differ from other 11 communication cables and require more planning and design Consideration should be 12 undertaken at the start of the design for 13

a) Future expansion 14

b) Type of splicing to be used (fusion andor mechanical) 15

c) Type of connectors to be used 16

d) Patching of fiber strands to complete a communication path and subsequent location of 17

patch panels and splice enclosures 18

e) Level of system reliability required that may impact the routing 19

f) Pole clearance requirements when run overhead within or exiting a substation 20

g) Right of way or easements for boring or installing underground conduit when exiting a 21

substation 22

With fiber cable system designs the use of lasers in equipment designed for long fiber runs 23 may result in overdriving the receiver photodiode on shorter runs which can cause the fiber 24 link to fail 25

Impurities in the glass fibers degrade the light signal within the fiber depending upon the 26 wavelength of the transmitted light and the distance between transmitter and receiver When 27 the signal is transmitted over great distances optical regenerators may be required to boost 28 signal strength 29

The following clauses specifically address cable route design routing electrical segregation 30 and separation of redundant cable 31

651 Cable route design 32

Fiber optic cable route design is more than just a raceway design where Annex E contains 33 more details on electrical cable raceway design and Annex I contains information on 34 diversityredundancy 35




Fiber optic cable route design includes raceway support hardware splice enclosures and 1 patch panels Splicing is integral to the enclosures and patch panels 2

6511 Raceway 3

When fiber optic cables are installed in raceway without electrical conductors raceway fill is 4 not required raceway fill is required when optical fiber is located within the same raceway as 5 electrical cable (NEC 2011 [B144]) 6

The substation fiber optic cable raceway will be different inside and outside the substation 7 control building Inside the control building use of cable tray and conduit is common Trays 8 and conduit dedicated for fiber runs may be colored yellow or orange for the specific 9 application When installed in its own raceway that raceway should be supported per TIA-10 569-C [B5] NEC Article 770 [B144] contains the installation requirements for raceways that 11 support fiber optic cables and compositehybrid cables which combine optical fibers with 12 current-carrying metallic conductors 13


One of the types of conduit used for buried fiber optic cable is the continuous-reeled type 21 Such continuous duct is popular because it is inexpensive and may offer enough protection to 22 allow the use of less expensive cable constructions 23

Transitions from indoor plant to outdoor plant require careful planning when not using 24 indooroutdoor rated fiber optic cable Proper patch panel placement is required to provide 25 proper transitioning between outdoor only cable to indoor only cable 26

For better transient avoidance use all-dielectric cable within appropriately sized PVC conduit 27 where rodent protection is required 28

6512 Support hardware 29

Support hardware is used for connecting the cable to support structures such as poles or 30 towers Fiber optic cable can include a messenger wire when not using ADSS cable trunions 31 with a cushion for a typical pole connection deadend ties storage loops etc 32

For OPGW hardware can be dependent on existing transmission line structures and design if it 33 is replacement of an existing static wire For a new transmission line there are different types 34 of supports available 35

For OPGW hardware see IEEE Std 1138 [B95] For ADSS hardware see IEEE Std 1222 36 [B99] 37

For storage loops there are H frames cross arms or spools available for poletower mounting 38 that can be used with or without a splice enclosure mounting These are typically used to store 39 the extra cable needed to remove the splice enclosure and bring it down to a hut or splice 40




trailer for additional splicing or testing Other types of storage units exist that are typically for 1 slack storage that can be utilized for restoration and repairs It is preferred to have stored fiber 2 built into the design 3

Particular care for the cable jacket is very important with fiber optic cables Tight tie wraps 4 staples clamps and such that may be acceptable for electrical cables should not be used with 5 fiber cables Non-metallic cable straps (with ultraviolet protection and other proper 6 environmental ratings) may be used 7

6513 Splice enclosures 8

Splice enclosures are sealed canisters that mount on distribution or transmission poles with a 9 storage loop or can also be hung from a cable These contain splice trays for splicing between 10 two or more fiber optic cables There are multiple sizes of enclosures depending on the cable 11 types counts and number of splices to be housed in the enclosure Bullet resistant covers are 12 available for these as well if required Splice enclosures for fiber optic applications are 13 required to seal so they prevent moisture from entering the closure Moisture is detrimental to 14 the fiber splices Splice installation procedures may include a pressure test to verify that the 15 assembly has been executed properly and that there are no leaks For example 5 psi may be 16 pumped into the closure through an air valve and soapy water sprayed in the sealing areas to 17 identify any leaks 18

Qualified products can withstand use in a variety of environments such as inside plant outside 19 plant below ground above ground etc 20

Splice enclosures may also be required in an underground location either in a handhole or 21 splice vaults GR-902 provides requirements for handholes and other below-ground non-22 concrete splice vaults 23

6514 Patch panels 24

Patch panels come in a variety of types from very small housing only 4 count fiber strand 25 cables to very large housing multiple large count fiber strand cables Patch panels can be 26 ordered with pre-terminated fiber pigtails pre-terminated fiber cable of specified length or no 27 pre-terminated connectors to the patch panel The pre-terminated type is preferred as field 28 termination of fiber is very tedious and requires high precision for acceptable losses at the 29 connectors Larger patch panels are typically located in a communications rack in substations 30 and smaller patch panels in yard cabinets 31

Patch panels typically include connectors splice trays splice protectors hook and loop cable 32 tie-downs fiber management spools and built-in strain relief lugs for securing fiber cable 33

When patch panels are installed on the front of cabinets the front rails should be recessed at 34 least 102 cm (4 in) to provide room for cable management between the patch panels and 35 cabinet doors and to provide space for cabling between cabinets Similarly if patch panels are 36 to be installed on the rear of cabinets the rear rails should be recessed at least 102 cm (4 in) 37

Patch panels should not be installed in a manner that prevents service access 38

Some implementers believe patch panels to be potential points of failure and prefer to 39 minimize or avoid such connections as much as possible Patch panels and the additional 40 connections can impact the overall systemrsquos reliability 41




Patch panels should be used to maintain system flexibility in a substation to accommodate 1 frequent adds moves and changes Patch panels may require additional space in racks and 2 cabinets They are also used to provide a centralized location for testing and monitoring 3

6515 Splicing 4

The most common type of splicing although the machines are expensive is fusion splicing 5 due to accuracy and speed Mechanical splices are less expensive but generally require more 6 time for installation and typically have losses ranging from 02 to over 10 dB depending on 7 the type of splice Fusion splicing have lower losses usually less than 01 dB where a loss of 8 005 dB or less is usually achieved with good equipment and an experienced splicing crew 9

Mechanical splicing is also performed but these can be larger and take up more space in a 10 splice tray When mechanical splices are used the size of the splice tray needs to be confirmed 11 to properly contain the splices 12

Splicing of all fibers in a cable may or may not be required The number of splices required 13 balances current needs against splicing time and costs 14

652 Routing 15

Fiber optic cable routing follows the same principles as described in Annex F However 16 unlike electrical conductors fiber optic cables have patch panels for interconnecting fibers that 17 are similar to termination cabinets or terminal blocks for metallic conductor cables However 18 there is a significant difference because optical fibers are commonly spliced as an accepted 19 practice 20

The designer should plan the route using a detailed written plan of installation for each 21 required run of fiber cable This plan includes the fiber cable specification location of 22 equipment patch plans splice details testing requirements data forms for testing personnel 23 experience level and assignment installation methods identification of potential problem 24 areas safety issues etc 25

The cable length should be long enough for the run because fiber splicing is expensive and 26 complicates the design installation and testing The cable route should not include any bends 27 that exceed the cable bend radius 28

Use patch panels to terminate cables inside the control building and inside yard cabinets 29

Fiber optic cable routing should follow the requirements of TIA-569-C [B5] regardless of 30 support for Ethernet Care should be used when routing fiber cables through areas with 31 different environmental requirements 32

NEC 2011 Article 77048 [B144] provides guidance on optical fiber cable that enters a 33 building Unlisted conductive and nonconductive outside plant optical fiber cables are 34 permitted in building spaces other than risers ducts used for environmental air plenums used 35 for environmental air and other spaces used for environmental air This is allowed only when 36 the length of the cable within the building from its point of entrance does not exceed 50 ft the 37 cable enters the building from the outside and the cable is terminated in an enclosure like a 38 patch panel or splice enclosure This exception allows for reasonable conversion from outdoor 39 cable to indoor cable at a convenient location Nonconductive fiber optic cable does not need 40 to be listed and marked where the cable enters the building from the outside and is run in 41




raceway consisting of Intermediate Metal Conduit (IMC) Rigid Metal Conduit (RMC) Rigid 1 Polyvinyl Chloride Conduit (PVC) and Electrical Metallic Tubing (EMT) 2

Once the cable system is completely designed calculate the link loss budget or power link 3 budget or optical budget This calculation is based upon the fiber characteristics number of 4 splices and connectors and transmitter power and receiver sensitivity If the calculated losses 5 are too great the design process needs to be redone looking for ways to decrease losses such 6 as reducing the number of splices or improving the fiber performance If the fiber run is too 7 short the transmitter power may overwhelm the receiver causing the link to fail 8


Electrical segregation is not required for non-conductive and conductive fiber optic cable but 10 may be considered whenever copper and fiber cables reside in the same raceway In this case 11 use of innerduct or other means of providing a dedicated raceway can be considered It is 12 becoming more common to install a separate cable tray system for communication cables in 13 substations thereby segregating control and power cable from communication cables This is 14 required in other types of buildings such as data centers and IT rooms By segregating the two 15 types of cables the installation reduces the risk of bend radius and crush-load violations of the 16 fiber optic cables 17

In cable tray and trench fiber optic cable may be subjected to stress due to the weight of other 18 cables which can induce micro-bending into the fiber optic cable Therefore it is a common 19 practice to place the fiber optic cable in a separate duct installed in the tray trench or conduit 20 (usually plastic) or use a cable construction with an integral duct This not only protects the 21 cable but also allows easier identification from metallic cables 22


Since fiber optic cables also include splice closures and patch panels consideration should be 24 given to keeping these facilities separated as well as the redundant cable 25


Transient protection is not required due to the inherent properties of the fiber unless metallic 27 armored cable is used Unless armored fiber is used Annex G is not applicable Use of 28 armored cable should be avoided within the substation due to the grounding requirements for 29 the armor Armored fiber optic cable may be exposed to lightning induced AC voltage or 30 other foreign electrical surges To help protect personnel and equipment a low resistance path 31 to ground or ldquogrounding pointrdquo should be provided at any location where the cable armor is 32 exposed such as splice joints and cable ends 33

Bonding and grounding of metallic armored fiber optic cable is often misunderstood or 34 overlooked The NEC [B144] and several industry standards promote safe and effective 35 bonding and grounding practices NEC Article 770 [B144] classifies a fiber optic cable 36 containing non-current-carrying metallic components such as armor or metallic strength 37 members as conductive This is why conductive fiber optic cables are bonded and grounded as 38 specified in NEC-2011 Article 770114 [B144] Besides the NEC ANSITIA-568-C [B10] 39 ANSITIA-569-B [B5] and ANSITIA-607-B [B26] also provide additional guidance Data 40 centers have also relied on ANSITIAEIA-942 [B11] Some locations may have specific local 41




codes for grounding and bonding that may differ from the NEC and industry standards 1 Always consult the local authority having jurisdiction with specific questions regarding 2 compliance 3

Specific criteria for bonding and grounding a fiber optic system with metallic armored cable is 4 necessary When all the components of a system are properly bonded together and grounded to 5 the earth the risk associated with electrical current harming personnel or damaging property 6 and equipment is reduced The following steps should be followed 7

The first step is to bond the cable armor to the bonding conductor when the armor is exposed 8 A bonding conductor is typically a short length of copper wire that can be strandedsolid 9 insulatedcovered or bare such as 6-AWG copper strand that complies with both the NEC 10 [B144] and ANSITIA-607-B [B7] 11

The bonding conductor can be attached to the armor by the use of a listed clamp lug or 12 connector as stated in the NEC Once the clamp is installed vinyl tape can be applied around 13 the clamp and exposed armor to protect the installer and the fiber from any sharp edges where 14 the armor is exposed 15

For the metallic armor fiber optic cable to be fully grounded the bonding conductor is bonded 16 ultimately to earth by connecting the bonding conductor to a dedicated path back to a ground 17 grid or ground rod When inside a substation control building the dedicated path can be a 18 direct run or created by attaching to a rack or cabinetrsquos bonding system that eventually 19 connects to the substation ground grid 20


There may be special design considerations requiring maximum pulling tension or minimum 22 bending radius that cannot be calculated using the guidelines in Annex J Fiber optic cable 23 pulling should follow the requirements of TIA-568-C [B10] In other situations follow the 24 guidelines from the cable manufacturer 25

Depending on the cable construction the maximum allowable pulling tension on fiber optic 26 cable on short runs of non-self-supporting cable can vary from 200 N (45 lb) to more than 27 3000 N (680 lb) The maximum allowable tension for a particular fiber optic cable should be 28 obtained from the cable manufacturer This maximum recommended pulling tension should be 29 noted on any drawings installation instruction etc The theory of pulling tension is the same 30 for fiber optic cable as it is for metallic conductor cable Pulling tension can be calculated 31 based on cable weight conduit system design and coefficient of friction 32

Fiber optic cables are often pulled for much longer distances than metallic conductor cables 33 especially OPGW and ADSS runs originating from outside the substation These long pulls 34 minimize the number of splices in fiber optic cable which introduce losses and reduce fiber 35 performance The light weight of the cable internal tension members and tube or duct in the 36 cable itself makes these long pulls possible Proper lubrication and good conduit installation 37 are also necessities 38

The special nature of fiber optic cable pulling ie long pull lengths and longer pull durations 39 require unique lubricants Lightweight fiber optic cable rubs on all sides of the conduit through 40 the natural undulation of long straight runs Many common lubricants flow to the bottom of 41 the raceway and lose effectiveness in this type of pulling 42




For ADSS cable tension see IEEE Std 1222 [B99] For OPGW cable tension see IEEE Std 1 1138 [B95] For wrapped cable tension see IEEE Std 1594 [B102] 2


Since optical fibers have only a thin buffer coating the fibers alone should be carefully 4 handled and protected to prevent damage The glass fibers are usually well protected by buffer 5 tubes duct armor etc which are part of the cable construction Even though the glass in the 6 fiber is actually stronger (higher tensile strength per unit area) than a metal conductor there is 7 very little cross-sectional area in a fiber available for strength and support For this reason 8 most fiber optic cables have other components to provide the strength for cable support during 9 pulling handling etc 10



In order to support the full speed and capability of fiber optic cables it is essential that the 14 fiber cables be installed with care to avoid kinks and excessive attenuation whenever the 15 cables are placed vertically or bent Avoiding kinks and sharp bends is essential to the life of 16 the fibers as well as their performance TIA-568-C [B10] provides cabling installation 17 requirements for fiber optic cables used for Ethernet which can also be applied to other non-18 Ethernet applications (ie serial communications) 19

Fiber optic cable installations in the US should meet the requirements of the National 20 Electrical Safety Code (NESC) (Accredited Standards Committee C2-2012) Although the 21 National Electrical Code (NEC) (NFPA 70 )[B144] is not applicable to substations under the 22 exclusive control of electric utilities it provides valuable guidance 23

Fiber optic cables in substations can be installed in the same manner as metallic conductor 24 cables however this practice requires robust fiber optic cables that can withstand normal 25 construction handling and still protect the fibers inside There are important differences to be 26 considered in the handling and installation of fiber optic cable as compared to metallic 27 conductor cable 28

Probably the most common installation mistake is making tight bends in the cable Tight 29 bends kinks knots etc in fiber cable can cause micro-cracking or growth of flaws in the 30 fiber with resulting loss of performance Minimum bending radius in fiber optic cable is 31 typically in the range of 20 times the cable diameter This bending radius should be considered 32 by the engineer when specifying conduit bends and pull box openings or sizing guide pulleys 33 sheaves mid-assist capstans etc 34

As with metallic conductor cable specific coefficients of friction depend on cable jacket type 35 conduit type and the lubricant as well 36

Short-length fiber optic cable pulls may not require lubricant however for long or complex 37 cable pulls lubricant is critical to making an efficient high quality installation The 38 requirements for fiber-optic cable pulling lubricant are the same as those for metallic 39 conductor cable 40




a) Compatibility with cable outer covering tube or duct 1

b) Complete and even coating on the cable for friction reduction at all friction points 2

c) Consistent low coefficient of friction (over time) 3

The eventual bandwidth available is highly dependent upon the quality of the workmanship 4 exhibited in termination of fiber optic cables Glass fiber optic connector performance is 5 affected both by the connector and by the glass fiber Concentricity tolerances affect the fiber 6 fiber core and connector body The core optical index of refraction is also subject to 7 variations Stress in the polished fiber can cause excess return loss The fiber can slide along 8 its length in the connector The shape of the connector tip may be incorrectly profiled during 9 polishing This may cause the performance to be below the manufacturers specification 10

For installation of OPGW (see IEEE Std 1138 [B95]) For ADSS installation see IEEE Std 11 1222 [B99] For wrapped cable installation see IEEE Std 1594 [B102] 12


Testing fiber optic cables connectors splices and closures fall into two categories factory 14 testing and field testing Factory testing is sometimes statistical for example a process check 15 A profiling system may be used to check that the overall polished shape is correct and a good 16 quality optical microscope may be used to check for blemishes Optical Loss Return Loss 17 performance is checked using specific reference conditions against a reference-standard 18 singlemode test lead or using an ldquoEncircled Flux Compliantrdquo source for multimode testing 19 Testing and rejection (ldquoyieldrdquo) may represent a significant part of the overall manufacturing 20 cost 21

Field testing is usually simpler depending on the fiber run and splicing A special hand-held 22 optical microscope is used to check for dirt or blemishes and an optical time-domain 23 reflectometer (OTDR) used to identify significant point losses or return losses A power meter 24 and light source or loss test set may also be used to check end-to-end loss Fiber optic cable 25 should always be tested on the reel prior to installation after installation after splicing and 26 then each fiber strand end-to-end Damage can occur to the fiber during any one of these 27 operations which may make one or more fibers unusable if the problem cannot be fixed 28

Prior to commissioning each fiber strand should be tested from both ends for both attenuation 29 and light levels although IEEE Std 1138 [B95] does not require every strand of OPGW be 30 tested It is imperative to test both directions to avoid the ldquoblindrdquo spots associated with the 31 cable terminations If these cable test records are stored for future reference degradation of the 32 network can be identified during maintenance 33

The IEC 61300 series provides basic test and measurement procedures for interconnecting 34 devices and passive components such as connectors splices and closures GR-771 provides 35 testing requirements for fiber optic splice closures 36

For optical Ethernet cables splices are allowed a maximum of 03 dB loss per the EIATIA-37 568-C [B10] standard This loss per splice may also be applied to any optical cable 38

The use of lasers in equipment configured for long fiber runs may result in overdriving the 39 receiver photodiode on shorter runs which can cause data errors In addition to checking the 40 received optical power level for excessive attenuation the installer should also check that the 41




maximum receive level is not exceeded If this occurs the use of an inline attenuator may be 1 required 2

Care should also be exercised when using laser transmitters at long wavelengths and high 3 speeds such as 1300 nm 1000BASE-LX over multimode fiber A phenomenon known as 4 differential mode dispersion (DMD) can cause received data errors even when the optical 5 power is within limits Mode conditioning cables can be used to reduce or eliminate these 6 effects Decade-old 625125 micron cable is especially susceptible to DMD 7

For testing of OPGW see IEEE Std 1138 [B95] For testing of ADSS see IEEE Std 1222 8 [B99] For wrapped cable testing see IEEE Std 1594 [B102] 9


7 Low-voltage power cable (ac and dc lt= 1 kV) 11

Low-voltage power cables are designed to supply power to utilization devices of the substation 12 auxiliary systems rated 1000 V or less 13

71 General 14

Low-voltage power cables are designed to supply power to utilization devices of the substation 15 auxiliary systems rated 1000 V or less This may include but is not limited to low voltage 16 power for station lighting receptacles control room auxiliary power motors switches 17 transformers batteries etc Substation services include both AC and DC voltages 18

Cables range in size from 14 AWG to 2000 kcmil Triplex single conductor and three 19 conductors per cable are typical cable constructions Both copper and aluminum conductors 20 are used with copper cables being more common 21

In the United States cables are usually designed and constructed in accordance with NEMA 22 WC 70ICEA S-95-658 [B141] UL 44 [B165] UL 83 [B166] or UL 854 [B167] 23


Differing conditions within a substation need to be examined to determine the appropriate 25 cable to be used Some considerations are ambient temperature length and location of cables 26 nominal system voltages expected fault levels normal and emergency loading conditions and 27 expected lifetime of the systems or substations 28






See IEEE Std 835 for sizes based on ampacity and other factors 3


In the past some users found it prudent to install cables with insulation rated at a higher 5 voltage level of 1000 V to prevent failures caused by inductive voltage spikes from de-6 energizing electromechanical devices eg relays spring winding motors The improved 7 dielectric strength of todayrsquos insulation materials prompted most utilities to return to using 600 8 V rated insulation for this application Low-voltage power cable rated 600 V and 1000 V is 9 currently in use 10





Consideration should be given to minimize insulation deformation when cable diameters differ 15 greatly Consideration should also be given when dealing with cables that do not have 16 compatible operating temperatures andor different voltage ratings When cable classifications 17 are mixed the power cable ampacity is calculated as if all the cables were power cables 18

Segregating low-voltage power cables in the substation cable trench or cable tray system is 19 generally not necessary In areas where low-voltage power cables are not normally expected 20 it may be necessary to segregate or identify these cables to help increase personnel safety 21 awareness 22








When single conductors are used in trays for two-wire or three-wire power circuits cables 5 should be trained and securely bound in circuit groups to prevent excessive movements caused 6 by fault-current magnetic forces and to minimize inductive heating effects in tray sidewalls 7 and bottom 8

Consideration of circuit voltage drop may lead to cables larger than the available space in 9 typical service panels and connectors Typical enclosure sizes and entryways may be replaced 10 with larger enclosures and entryways in the design phase to account for the larger cable sizes 11 or multiple conductors per phase This may reduce the possibility of for example having to 12 use conductor reducing terminal connectors within an enclosure due to limited interior space 13 or bending radius constraints 14


Consideration should be given to using stress cones or stress relief at termination points for 16 cables operating at circuit voltages greater than 600 volts 17


Low-voltage power cables may be insulation-resistance tested prior to connecting cables to 19 equipment These cables may be tested as part of the system checkout 20

The low-voltage power cable insulation resistance tests should measure the insulation 21 resistance between any possible combination of conductors in the same cable and between 22 each conductor and station ground with all other conductors grounded in the same cable 23

8 Medium voltage power cable (1 kV to 35 kV) 24

Medium-voltage power cables are designed to supply power to substation utilization devices 25 other substations or customer systems rated higher than 1000 V 26

NOTEmdashOil-filled and gas-insulated cables are excluded from this definition and are not covered in this guide 27

The design of medium voltage power cable systems is dependent on many factors including 28 system nominal voltage system fault level voltage drop conductor material insulation and 29 shielding material type of ductwork (whether direct buried or in duct) phase spacing (and 30




conductor spacing) phase arrangement number of conductors installed method of shield 1 grounding earth thermal resistivity ambient temperature current loading load cycling and 2 load factor These factors make it important to consult industry codes 3




Phase transposition andor proximity heating should be considered for long runs of medium-7 voltage power cables See IEEE Std 835 8

822 Voltage rating and insulation level 9

For medium-voltage cables it is usual practice to select an insulation system that has a voltage 10 rating greater than the expected continuous phase-to-phase conductor voltage For solidly 11 grounded systems (with rapid fault clearing) the 100 insulation level is typically selected 12 The 133 insulation level is typically applied on systems where clearing time exceeds one 13 minute but does not exceed one hour The 173 insulation level is typically applied where 14 the time until de-energization can exceed one hour or is indefinite The delayed clearing times 15 are typically used with high-impedance-grounded or ungrounded systems (such as a delta 16 system) where continuity of operations or an orderly shutdown is critical The 133 and 17 173 insulation levels may also be selected where the application meets the requirements of a 18 lower level but additional thickness is desired 19


A shielded construction is typically used for 5 kV and higher rated cables The use of shielding 21 and shield grounding of medium-voltage power cables can reduce or minimize deterioration of 22 cable insulation or jackets caused by surface discharges (electrical stress) helps reduce the 23 hazard of shock to personnel and helps confine the electric field within the cable 24

A shield screen material is applied directly to the insulation and in contact with the metallic 25 shield It can be semiconducting material or in the case of at least one manufacturer a stress 26 control material At the high voltages associated with shielded cable applications a voltage 27 gradient would exist across any air gap between the insulation and shield The voltage gradient 28 may be sufficient to ionize the air causing small electric arcs or partial discharge These small 29 electric arcs burn the insulation and eventually cause the cable to fail The semiconducting 30 screen allows application of a conducting material over the insulation to eliminate air gaps 31 between insulation and ground plane 32

Various shield screen material systems include the following 33

a) Extruded semiconducting thermoplastic or thermosetting polymer 34




b) Extruded high-dielectric-constant thermoplastic or thermosetting polymer referred to 1 as a stress control layer 2


Medium-voltage power cable circuits are recommended to be installed in dedicated raceways 4 Control protection instrumentation and communications circuits should not be installed in the 5 same raceway as the medium voltage cables unless separated by a solid fixed barrier When 6 installing cables in cable trays medium-voltage power cables should be installed in a single 7 layer The sum of the cable diameters should not exceed the cable tray width 8



An additional function of shielding is to minimize radio interference The selection of the 11 shield grounding locations and the effects of single and multiple grounds are points to be 12 considered for the proper installation of shielded cable The shielding recommendations 13 contained in IEEE Std 575 should be followed 14


Medium-voltage power cables should be segregated from all other cables and installed so that 16 their voltage cannot be impressed on any lower voltage system Methods for achieving this 17 segregation include the following 18

c) Installation of medium-voltage cables in raceways that are separated from low-19 voltage power and control cables and from instrumentation cables Installation of 20 different voltage classes of medium-voltage power cables in separate raceways is also 21 recommended Cables installed in stacked cable trays should be arranged by 22 descending voltage levels with the higher voltages at the top 23

d) Utilization of armored shielded cables (separate raceways are still recommended) 24



For additional information on pulling of dielectric power cables see AEIC CG5 [B1] 27






The ends of medium-voltage power cables should be properly sealed during and after 3 installation 4


Shielded and unshielded medium-voltage cables should not be subjected to high-voltage dc 6 tests insulation resistance tests are recommended (IEEE Std 400 [B53]) 7





Annex A 1

(informative) 2

Flowchart 3

Figure A1 shows the flowchart process for design and installation of cable systems in 4 substations 5




START

Determine Service Conditions

Cable Selection

Determine Voltage Rating

Determine Cable Charactiristics Required

Determine Cable Construction Required

Are Communication Cables Applied

Is a New Cable Raceway Design Required

Route Cables in Raceway

Recheck that Conductor Sizing Cable Characteristics and Cable Construction

are Still Appropriate

Does Electrical Segregation Need to be

Considered

Is a Redundant Separate Cable Required

Are Cable Pulling Tensions Required

Ensure Proper Handling

Installation

Acceptance Testing

Determine Recommended Maintenance

Finish

User Design Checklist

Undertake Cable Raceway Design

Determine Electrical Segregation Required

Determine Separate Cable Requirements

Undertake Cable Pulling Tension Calculations

Yes

Yes

Yes

Yes

Yes

Determine Transient Protection

Annex B

Annex C

Annex D

Annex E

Annex F

Annex G

Annex H

Annex I

Annex J

Annex G

Annex K

Annex L

Annex M

Annex N

No

No

No

No

1 Figure A1mdash Flowchart process for design and installation of cable systems in 2

substations 3




Annex B 1

(normative) 2

Service conditions for cables 3

The service conditions for electrical cables are as follows 4

a) Cables should be suitable for all environmental conditions that occur in the areas 5 where they are installed (see ICEA and NEMA standards on cable for information 6 concerning cable ratings) 7

b) Cable operating temperatures in substations are normally based on 40 degC ambient air 8 or 20 degC ambient earth Special considerations should be given to cable installed in 9 areas where ambient temperatures differ from these values as noted below 10

c) Cables may be installed in a variety of methods including direct buried duct banks 11 conduits and trenches below ground or in cable trays conduits and wireways above 12 ground or any combination thereof Cable may be required to be suitable for 13 operation in wet and dry locations 14

d) Where practical the service life of the cable should be at least equal to the service life 15 of the equipment it serves or the design life of the substation 16

e) Consideration should be given to the expected duration of emergency loading and 17 fault levels 18

Items c and d also apply to communication cables Note that environmental conditions that 19 are contained within IEEE Std 1613 [B103] and IEC 61850-3 [B63] should be carefully 20 considered for any cables connecting to devices that are compliant to these standards 21 especially communications cables An IED whose performance exceeds that of a connected 22 communications cable is likely to suffer communication performance issues when the 23 temperatures exceed the ratings of the cable but not the IED In this case depending upon 24 the applications and function of the IED a cable failure may be just as serious as an IED 25 failure When selecting the cabling for IEDs specifically communication cable confirm 26 that the cablersquos temperature ratings and IED temperature ratings are within the same 27 acceptable range This allows the cable to perform when each IED is operating within its 28 specified range 29

Note that some communications specifications include specific cable requirements For 30 example the USB 20 cable specification requires an operating temperature range from 0 degC 31 to +50 degC and be UL listed per UL Subject 444 Class 2 Type CM for Communications 32 Cable Requirements Copper and fiber cables used for Ethernet have specific cable 33 requirements in TIA 568-C0 [B10] where additional requirements are found in TIA 1005 34 for industrial premises 35

TIA 1005 and TIA 568-C0 [B10] include a ldquoMICErdquo classification for Mechanical Ingress 36 ClimaticChemical and Electromagnetic environments The MICE concept was founded in 37 Europe during the development of EN 50173-3 but is now completely harmonized at the 38 international level in IEC 24702 [B116] IEC 61918 [B62] TIA 1005 [B8] and TIA 568-39 C0 [B10] The MICE concept allows the description of the environmental conditions in a 40




precise and unambiguous way But it should be noted that the MICE classification system 1 is not a component test specification does not replace existing international or national 2 standards and existing international or national standards for components contain the test 3 requirements and schedules for product qualification Note that MICE does not cover all 4 environmental characteristics as security problems such as protection against manipulation 5 and attack safety for people and animals fire hazard and explosion risks are not covered 6 by the MICE classifications In every case national laws and standards as well as safety 7 regulations are taken into consideration 8

Substation communication cabling may traverse areas with a wide range of environments 9 or may be localized along a cabling channel The MICE environmental classification is 10 stated with the use of subscripts (MaIbCcEd) where a b c and d are sub-classifications that 11 are numbered from 1-3 These sub-classifications relate to the severity of the 12 environmental parameter where the most benign environmental classification is described 13 as M1I1C1E1 and the harshest environmental classification is described as M3I3C3E3 For 14 example the parameters for the climatic (C) element may be C1 in one parameter and 15 another parameter may be C3 Since the harshest parameter severity applies the climatic 16 classification would be C3 This applies to the other classifications so if the ingress 17 classification is I1 the climaticchemical classification is C3 and the electromagnetic 18 element is E2 this mixed environmental classification could be stated as M1I1C3E3 The 19 severity of each MICE element is based upon the parameter with the worst-case harshness 20 within the element Tables in this annex show a complete listing of elements and 21 parameters except for the chemical characteristics See TIA TSB-185 for tutorial 22 information on the MICE classification system 23

Table B1mdashReference for specific parameter boundaries for the mechanical 24 classification 25

Parameter M1 M2 M3 Shock and bump in peak acceleration Note that for bump the repetitive nature of the shock experienced by the channel should be taken into account

IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8

40 msminus2 100 msminus2 250 msminus2 Applies to areas in a commercial office building where products are mounted on light structures subject to negligible vibration

Applies to areas close to heavy machinery

Applies to areas on with extremely high vibrations such as power hammers

IEEE Std 1613 not specified IEC 61850-32002 references IEC 60870-2-2 clause 4 which

states class Bm applies to substations and references IEC 60721-3 Value is 100 msminus2 with a half sine duration of 11 ms

Vibration in displacement amplitude (2 Hz to 9 Hz) and acceleration amplitude (9 Hz to 500 Hz)

IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8

15 mm 70 mm 150 mm 5 msminus2 20 msminus2 50 msminus2 Applies to areas in a commercial office building where products are mounted on light structures subject to negligible vibration







states class Bm applies to substations and references IEC 60721-3 Ranges are

10-15 msminus2 over a frequency range of 2 ndash 9 9 ndash 200 200 ndash 500 Hz with a displacement of 30 mm

Crush (TSB-1852009)

IEC 61935-2 and IEC 61935-2-20 Test IEC 61935-2-20

There is no specific difference in the references Crush (ISO 24702-2006)

45 N over 25 mm (linear) min

1 100 N over 150 mm (linear) min


IEEE Std 1613 not specified IEC 61850-3 not specified

Impact (TSB-1852009)

IEC 61935-2-20 There is no specific difference in the references

Impact (ISO 24702-2006)

1 J 10 J 30 J IEEE Std 1613 not specified IEC 61850-3 not specified

Tensile force (TIA-568-C)

This aspect of environmental classification is installation-specific and should be considered in association with IEC 61918 and the appropriate component specification


Bending flexing and torsion (TIA-568-C)



From the comparisons in the tables above the MICE mechanical element for a substation 1 can be M2 if using IEC 61850-3 [B63] but when using IEEE 1613 [B103] no specific 2 requirements results in a user specification of the mechanical element 3

The I classification or ingress can be related to IP (ingress protection) code defined in IEC 4 60529 [B55] that uses a system of two numerical digits to define the level of both foreign 5 object and moisture protection The highest level for MICE I3 designates environments 6 that can be correlated to both IP codes and NEMA enclosures 7

Table B2mdashDescription of protection level for first number in IP code 8

Number Description Definition 0 Not protected 1 Protected against solid foreign objects of 50 mm diameter and

greater 2 Protected against solid foreign objects of 125 mm diameter

and greater 3 Protected against solid foreign objects of 25 mm diameter





and greater 5 Dust protected Protected from the amount of dust that would interfere with

normal operation 6 Dust tight No ingress of dust

Table B3mdashDescription of protection level for second number in IP code 1

Number Description Classification 0 Not protected 1 Protected against vertically falling

water drops Protected against vertically falling water drops

2 Protected against vertically falling water drops when enclosure tilted up to 15deg

Protected against vertically falling water drops when enclosure is tilted up to 15deg

3 Protected against spraying water Protected against water sprayed at an angle up to 60deg on either side of the vertical

4 Protected against splashing water Protected against water splashed against the component from any direction

5 Protected against water jets Protected against water projected in jets from any direction

6 Protected against powerful water jets

Protected against water projected in powerful jets from any direction

7 Protected against the effects of temporary immersion in water up to 1 m

Protected against temporary immersion in water up to 1 m under standardized conditions of pressure and time

8 Protected against the effects of continuous immersion in water

Protected when the enclosure is continuously immersed in water under conditions that are agreed between manufacturer and user but are more severe than for classification 7 This may not mean that water does not enter the cabinet only that entering water produces no harmful effects

Table B4mdashReference for specific parameter boundaries for the ingress 2 classification 3

Parameter I1 I2 I3 Particulate ingress (empty max)

No class No class No class 125 mm 50 μm 50 μm IP2x May be NEMA 1

IP4x

IP4x and IP5x May be NEMA 4 4X

IEEE Std 1613 not specified IEC 61850-3 references IEC 60654-4 as an applicable guideline

Immersion IEC 60529 and IEC 60664-1

No class No class No class




None Intermittent liquid jet le125 lmin ge63 mm jet gt25 m distance

Intermittent liquid jet le125 lmin ge63 mm jet gt25 m distance and immersion (le1 m for le30 min)

IPx0 IPx5 IPx5 IPx6 and IPx7 May be NEMA 4 4X 6 6P


The National Electrical Manufacturers Association (NEMA) 250 standard includes 1 protection ratings for enclosures similar to the IP code However the NEMA 250 standard 2 also dictates other product features not addressed by IP codes such as corrosion resistance 3 gasket aging and construction practices So it is possible to map IP codes to NEMA ratings 4 that satisfy or exceed the IP code criteria it is not possible to map NEMA ratings to IP 5 codes as the IP code does not mandate the additional requirements 6

Table B5mdashCross reference between IP Codes and NEMA enclosures 7

IP Code Minimum NEMA Enclosure rating to satisfy IP Code

IP20 1 IP54 3 IP66 4 4X IP67 6 IP68 6P

From the comparisons in the tables above the MICE ingress element for a substation can 8 be I1 I2 or I3 if using IEC 61850-3 [B63] as a guideline when using IEEE 1613 [B103] 9 there is no guidance 10

The C element climaticchemical is shown here for climatic only Chemical environments 11 are not typical to substations where the definition in IEC 60654-4 [B56] for Class 1 12 environments are those sufficiently well controlled so that corrosion is not a factor in 13 determining corrosion See ISO 24702 [B116] for the complete definitions of the chemical 14 characteristics 15

Table B6mdashReference for specific parameter boundaries for the climatic 16 classification 17

Parameter C1 C2 C3 Ambient temperature

ISOIEC 11801 IEC 60721-3-3 Class 3K8H

IEC 60721-3-3 Class 3K7

minus10deg C to +60 degC (connector only for C1) Note cable in referenced standard is minus20deg C to +60 degC

minus25deg C to +70 degC minus40deg C to +70 degC




Parameter C1 C2 C3 Applies to commercial premises that may consist of either a single building or of multiple buildings on a campus

Applies to entrances of buildings some garages in sheds shacks lofts telephone booths buildings in factories and industrial process plants unattended equipment stations unattended buildings for telecom purposes ordinary storage rooms for frost-resistant products and farm buildings

Applies to weather-protected locations having neither temperature nor humidity control

IEEE Std 1613 ndash20 degC to +55 degC



IEC 61850-3 IEC 60870-2-2 Class C1 (3K51K3) ndash5 degC to +45 degC

IEC 61850-3 IEC 60870-2-2 Class C2 (3K6) ndash25 degC to +55 degC


Temperature gradient

IEC 60721-3-3 Class 3K1

IEC 60721-3-3 Class 3K7

IEC 61131-2

01deg C min 10deg C min 30deg C min Applies to occupied offices workshops and other rooms for special applications

IEEE Std 1613 not specified IEC 61850-3 IEC 60870-2-2 Class C1 (3K51K3) 05deg C min

IEC 61850-3 IEC 60870-2-2 Class C2 (3K6) 05deg C min

IEC 61850-3 IEC 60870-2-2 Class C3 (3K71K5) 01deg C min

Humidity IEC 60721-3-3

Class 3K3 IEC 60721-3-3 Class 3K4

IEC 60721-3-3 Class 3K5

5 to 85 (non-condensing)

5 to 95 (condensing)





Parameter C1 C2 C3 Applies to normal living or working areas offices shops workshops for electronic assemblies and other electro-technical products telecommunications centers storage rooms for valuable and sensitive products

Applies to kitchens bathrooms workshops with processes producing high humidity certain cellars ordinary storage rooms stables garages For the more humid open-air climates they may also be found in living rooms and rooms for general use

Applies to some entrances and staircases of buildings garages cellars certain workshops buildings in factories and industrial process plants certain telecommunications buildings ordinary storage rooms for frost-resistant products farm buildings etc

IEEE Std 1613 states 55 relative humidity outside of the device or enclosure or cover for a temperature within the defined operational and nonoperational ranges with excursions up to 95 without internal condensation for a maximum of 96 h IEC 61850-3 IEC 60870-2-2 Class C1 (3K51K3) 20 to 75

IEC 61850-3 IEC 60870-2-2 Class C2 (3K6) 10 to 100

IEC 61850-3 IEC 60870-2-2 Class C3 (3K71K5) 10 to 100

Solar radiation IEC 60721-3-3

Class 3K3-3K6 IEC 60721-3-3 Class 3K7 IEC 60068-2-51975 contains a table covering wavelengths from UV to IR that totals 1 120 Wmminus2

700 Wmminus2 1120 Wmminus2 1120 Wmminus2


From the comparisons in the tables above the MICE climatic element for a substation can 1 be C1 C2 or C3 if using IEC 61850-3 [B63] but when using IEEE 1613 [B103] C3 should 2 be used 3

Table B7mdashReference for specific parameter boundaries for the 4 environmental classification 5

Parameter E1 E2 E3 Electrostatic discharge IEC 61000-6-1

IEC 61326 Electrostatic discharge ndash Contact (0667 μC) 4 KV

Electrostatic discharge ndash Air (0132 μC) 8 KV No description

IEEE Std 1613 specifies tests at all of the following levels contact discharge of 2 4 and 8 kV

air discharge of 4 8 and 15 kV IEC 61850-3 not specified




Radiated RF ndash AM IEC 61000-2-5 3 Vm at (80 to 1000) MHz

3 Vm at (1400 to 2000) MHz 1 Vm at (2000 to 2700) MHz

10 Vm at (80 to 1000) MHz 3 Vm at (1400 to 2000) MHz 1 Vm at (2000 to 2700) MHz

No description No description

IEEE Std 1613 specifies 20 Vm rms The waveform should be amplitude modulated with a 1 kHz sine wave Modulation should be equal to 80 with the resulting maximum field strength not

less than 35 Vm rms The test carrier frequency should be swept or stepped through the range of 80 MHz to 1000 MHz

IEC 61850-3 specifies either IEC 61000-4-3 class 3 (10 Vm) or IEEE C37902 (same reference as IEEE Std 1613)

Conducted RF IEC 61000-6-1

IEC 61326 IEC 61000-6-2 IEC 61326

3 V at 150 kHz to 80 MHz 10 V at 150 kHz to 80 MHz

No description No description IEEE Std 1613 does not specify IEC 61850-3 does not specify

Electrical fast transientBurst (EFTB) (comms)

IEC 61000-6-1 IEC 61000-2-5 IEC 61131-2

IEC 613262001 Annex A Table A1

500 V 1000 V 1000 V No description No description No description IEEE Std 1613 defines oscillatory and fast transient surge withstand capability (SWC) tests as distinct tests oscillatory is 2500 V and fast transient is 4000 V IEC 61850-3 specifies oscillatory waves per IEC 61000-4-12 class 3 (2000 V line to ground and 1000 V line to line) and common mode disturbances up to 150 kHz as per IEC 61000-4-16 level 4 (not shown here) and fast transient waves per IEC 61000-4-4 class 4 and above (4000 V on power ports and 2000 V on signal and control ports) IEC 61850-3 specifies surges as per IEC 61000-4-5 (test levels to class 4) with waveforms 1250 micros and 10700 micros and peaks up to 4000 V

Surge (transient ground potential difference) ndash signal line to earth

IEC 61000-6-2 500 V 1000 V 1000 V No description No description No description

IEEE Std 1613 does not specify IEC 61850-3 does not specify

Magnetic field (5060 Hz)

IEC 61000-6-1 IEC 61000-6-1 IEC 61000-6-2 IEC 61326

1 Amminus1 3 Amminus1 30 Amminus1 No description No description No description





Magnetic field (60 Hz to 20000 Hz)

No reference No reference No reference ffs ffs ffs No description No description No description


ldquoffsrdquo (for further study) are preliminary and are not required for conformance to ISO 24702

Note the ISO 24702 [B116] provides guidance for the classification of electromagnetic 1 environments in Annex F where distance from fluorescent lights is the most common for 2 application to substations When the distance is less than 015 m this is classified as E3 3 greater distances may be classified as E2 or E1 Resistance heating can also be common to 4 substation cabinets where a distance less than 05 m is classified as E2 and distances 5 greater may be classified as E1 From this information and from the comparisons in the 6 tables above the MICE electromagnetic element E for a substation can be E3 when using 7 IEC 61850-3 [B63] and IEEE 1613 [B103] 8 Note that for all above comparisons with IEC 61850-3 [B63] where equipment forms an 9 integral part of high voltage switchgear and control gear clause 2 of IEC 60694 [B57] 10 applies and is not taken into consideration here 11

To summarize a substation environment could be classified as M2I1-3C1-3E3 but this 12 depends significantly on the localized conditions and requirements for each substation 13 There also may be several different ratings for a substation environment one for the 14 control building and other for other areas like outdoor cabinets associated with circuit 15 breakers transformers capacitor banks and other outdoor electrical equipment Applying 16 the MICE concept to communication cables may allow for better selection of cables that 17 are appropriate for the substation environment Care should be used to identify when 18 cables are rated with their connectors or just the cables themselves It is common that 19 communication cable connectors are provided separate from the cable The ratings of the 20 connectors should be investigated because a connector failure can also lead to 21 communication degradation and even to complete failure 22




Annex C 1

(normative) 2

Control and power cable selection 3

This annex provides guidance for selection of metallic type cables for various types of 4 installations and applications The proper design of cable systems requires the consideration of 5 many factors These factors include circuit application ambient temperature conductor 6 temperature earth thermal resistivity load factor current loading system fault level voltage 7 drop system nominal voltage and grounding method of installation and number of 8 conductors being installed 9

C1 Conductor 10

The cable conductor is selected based upon cost-efficient material industry sizes ampacity 11 requirements voltage drop and short-circuit criteria The selection of power cables may also 12 include consideration of the cost of losses 13

C11 Material 14

One of the most important properties of a conductor material is its conductivity In 1913 the 15 International Electrotechnical Commission adopted the International Annealed Copper 16 Standard (IACS) that set the conductivity of copper to be 100 Conductors are typically 17 specified based on this standard 18

Copper conductor may be uncoated or coated with tin lead alloy or nickel Normally 19 uncoated conductor is used but coated conductor may be used to ease stripping of the 20 insulation from the conductor and to make soldering easier Note that soldering is not a typical 21 termination method for utilities 22

Aluminum conductor is usually electrical conductor grade which has a volume conductivity of 23 approximately 61 that of copper For the same diameter aluminum conductors have a lower 24 conductivity than copper Aluminumrsquos advantage is a 20 lower mass for equivalent 25 conductivity 26

Control and instrumentation cable conductor is almost always copper Aluminum conductor 27 may be considered for larger power cables Factors that influence the selection of either copper 28 or aluminum for conductors include 29

f) Aluminum metal has historically been less expensive than copper 30

g) Aluminum conductor terminations require special treatment copper terminations do 31 not 32

h) For equivalent ampacity aluminum conductor has a lower mass that makes it easier 33 to handle for larger cable sizes 34

i) For equivalent ampacity copper conductor is smaller and can be installed in smaller 35 raceways 36




C12 Size 1

Conductor size is measured by its cross-sectional area expressed in circular mils (cmil) or 2 mm2 One circular mil is defined as the area of a circle 1 mil (000 1 in) in diameter In North 3 America conductors below 250 kcmil are assigned American Wire Gauge (AWG) numbers 4 for easy reference The AWG number increases as the cross-sectional area decreases 5

1 cmil = 5067 times 10minus4 mm2 (07854 times 10minus6 in2) 6

Conductor size is selected to meet ampacity voltage drop and short-circuit criteria The 7 selection of power cables may include consideration of the cost of losses 8

C13 Construction 9

Conductors may be either solid or stranded Solid conductors may be used for sizes up to 12 10 AWG Solid conductors larger than 12 AWG are stiff and difficult to install therefore stranded 11 construction is normally used for these larger conductors Solid conductors are typically used 12 for building wiring or lighting circuits but typically not used for control and instrumentation 13

The number of strands and size of each strand for a given size is dependent on the use of the 14 conductor ASTM B8 [B14] defines the number and size of conductor stranding Common 15 stranding classes are summarized in Table C1 The number of strands per conductor is 16 standardized and is summarized in Table C2 Substation installations normally use Class B 17 stranding for most field and equipment-to-equipment circuits and Class K stranding for 18 switchboard (panel) wiring 19

Table C1mdashConductor stranding 20

Class Use

B Power cables C Power cables where more flexible stranding than Class B is desired D Power cables where extra flexible stranding is desired G All cables for portable use H All cables where extreme flexibility is required such as for use on take-up reels etc I Apparatus cables and motor leads K Cords and cables composed of 30 AWG copper wires

M Cords and cables composed of 34 AWG copper wires

Table C2mdashStranding construction 21

Class 14-2 AWG 1-40 AWG 250ndash500 MCM

B 7 19 37 C 19 37 61

D 37 61 91

G 49 133 259

H 133 259 427

K 41 (14 AWG) 65 (12 AWG)

- -




C2 Ampacity 1

C21 Ampacity for power cables 2

The ampacity of a cable depends on the temperature of the surrounding air or earth the 3 temperature rise of the cable materials and proximity to other cables The maximum 4 temperature usually occurs at the conductor-insulation interface The maximum allowable 5 insulation temperature limits cable ampacity 6

Maximum allowable insulation temperature has been determined through testing and 7 experience for the commonly used materials and is a function of time For example for XLPE 8 insulation 90 degC is the maximum acceptable continuous temperature 130 degC is the maximum 9 for the duration of an emergency and 250 degC is the maximum for very short time durations 10 (eg short circuits) The steady-state load short- time cyclic load emergency load and fault 11 conditions are usually considered in determining the ampacity required for a cable 12

Losses (I2R) in the conductor and magnetically induced losses in the insulation shield and the 13 raceway are the principal causes of the insulation temperature rise Shields or sheaths that are 14 grounded at more than one point may carry induced circulating currents and reduce the 15 ampacity of the cable The magnitude of circulating currents flowing in shields grounded at 16 more than one point depends on the mutual inductance between the cable shielding and the 17 cable conductors the mutual inductance to the conductors in other cables the current in these 18 conductors and the impedance of the shield 19

Below-ground cables are usually installed in trench or duct or direct buried Above-ground 20 cables are usually installed in conduit wireway tray or suspended between supports Cables 21 may be routed through foundations walls or fire barriers and raceway may be partially or 22 totally enclosed The installation that results in the highest insulation temperature should be 23 used to determine the ampacity of a cable routed through several configurations 24

If a number of cables are installed in close proximity to each other and all are carrying current 25 each cable will be derated The reason for derating is reduced heat dissipation in a group of 26 cables compared with a single isolated cable or conduit Group correction factors should be 27 used to find reduced ampacity of cables in the group 28

The cable materials themselves can affect heat transfer and ampacity For example the thermal 29 conductivity of EPR is lower than that of XLPE and the ampacity of the EPR cable will be 30 less for the same insulation thickness 31

The thermal conductivity of earth surrounding below-ground cables is one of the most 32 important parameters in determining ampacity There is significant variation of earth thermal 33 conductivity with location and time and IEEE Std 442 [B76] provides guidance for earth 34 conductivity measurements However many engineers have found it acceptable to use typical 35 values For a typical loam or clay containing normal amounts of moisture the resistivity is 36 usually in the range of 60 degC cmW to 120 degC cmW When the earth resistivity is not known 37 a value of 90 degC cmW is suggested in IEEE Std 835 38

The ampacity of below-ground cable is also dependent upon the load factor which is the ratio 39 of the average current over a designated period of time to the peak current occurring in that 40 period Ampacities for typical load factors of 50 75 and 100 are given in IEEE Std 835 41

Methods for determining ampacity and the tables of ampacities for a large number of typical 42 cable and below-grade and above-grade installation configurations are included in IEEE Std 43




835 In addition IEEE Std 835 includes guidance for determining ampacities for 1 configurations not included in the tables 2

Finite element techniques have been used to calculate below-ground cable ampacity These 3 techniques will allow the designer to account for specific cable construction and installation 4 details 5

C22 Ampacity for other cables 6

Ampacity of protection and control type cables are determined using applicable national codes 7 For example in the United States the NEC [B144] could be used 8

Most codes include derating factors that account for multiple conductors per raceways 9 However for randomly installed cables in tray the industry accepted method for determining 10 ampacity is given in NEMA WC 51ICEA P-54-440 [B139] 11

Cable ampacity should be equal to or larger than the trip rating of the rating of the circuit 12 overload protection which is typically 125 of the expected circuit load 13

C3 Voltage drop 14

Voltage drop should be considered when selecting conductor size The voltage drop 15 requirements should be such that the equipment operates within its design limits Voltage drop 16 for motor feeders should be considered for both starting and running conditions to help ensure 17 the motor operates within its design limits 18

Voltage drop is calculated according to Equation (C1) as follows 19

LS VVV (C1) 20

where 21

ΔV is the voltage drop 22 VS is the source voltage 23 VL is the load voltage 24 25

An exact solution for calculating voltage drop may be determined using Equation (C2) 26 however an iterative approach is required since the load voltage is not typically known 27

22 )sin()cos( IXVIRVV LLS (C2) 28

where 29

I is the load current 30 R is the conductor resistance 31 X is the load voltage 32 θ is the load power flow angle 33




Rather in this case the voltage drop can be approximated based on conductor impedance and 1 load current using Equation (C2b) as follows 2

sincos IXIRVVV LS (C3) 3

Equation (C3) is not suitable for power factors less than approximately 70 such as for 4 motor starting or larger cables with high reactance For situations like this Equation (C2a) 5 may be used Alternatively computer software may be used to determine the exact solution 6 Hand calculations will typically be done using the approximate solution 7

Voltage drop is commonly expressed as a percentage of the source voltage An acceptable 8 voltage drop is determined based on an overall knowledge of the system Typical limits are 3 9 from source to load center 3 from load center to load and 5 total from source to load 10

Voltage drop is normally based on full load current However there is often diversity in the 11 load on lighting and receptacle circuits and the actual load that may occur on a receptacle 12 circuit cannot be accurately predicted In calculating receptacle circuit load for determination 13 of conductor size a value of 60 of the receptacle rating is often used unless the actual load 14 is known 15

The calculation of voltage drop requires knowledge of the conductorrsquos impedance determined 16 as detailed in the following clause It is recommended that a voltage drop be calculated 17 initially at the maximum conductor operating temperature because the ampacity is based on 18 this too In cases where a cable will be sized based on voltage drop and one size is marginal for 19 voltage drop voltage drop may be recalculated at the expected cable operating temperature 20

C31 Cable impedance 21

The impedance of a cable may be determined from tables or by calculation Calculations are 22 commonly used for larger size high current cables since there may be many variables that 23 affect the impedance For small conductor sizes table values may be used with only a small 24 error 25

Table C3 provides parameters for common substation cables For other sizes refer to 26 manufacturer catalogs 27

Table C3mdash Parameters for common substation cables (600 V insulation) 28

Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)

Approximate outside diameter (OD)

Nonshielded Shielded

(AWG) (cmil) (mm) (in) (mm) (in)

18 1620 2608 795 2 14 84 0330 102 0400

4 112 97 0380 113 0445

7 98 114 0450 131 0515

12 7 157 0620 173 0680

19 7 183 0720 198 0780 16 2580 1637 499 2 18 90 0355 107 0420

4 144 104 0410 121 0475




Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)




7 126 123 0485 147 0580

12 9 169 0665 185 0730

19 9 197 0775 213 0840 14 4110 1030 314 2 25 97 0380 113 0445

4 20 112 0440 128 0505

7 175 132 0520 157 0620

12 125 183 0720 199 0780

19 125 213 0840 240 0945 12 6530 650 198 2 30 107 0420 123 0485

4 24 123 0485 147 0580

7 21 156 0615 171 0675

12 15 203 0800 230 0905

19 15 248 0975 264 1040 10 10 380 407 124 2 40 119 0470 136 0535

4 32 146 0575 163 0640

7 28 175 0690 191 0750

12 20 240 0945 257 1010 8 16 510 255 078 1 55 71 0280 104 0410

2 55 160 0630 177 0695

3 55 170 0670 185 0730

4 44 187 0735 203 0800 6 26 240 161 049 1 75 89 0350 114 0450

2 75 180 0710 197 0775

3 75 192 0755 208 0820

4 60 211 0830 237 0935 4 41 740 101 031 1 95 102 0400 127 0500

2 95 206 0810 232 0915

3 95 230 0905 245 0965

4 76 251 0990 268 1055 2 66 360 0636 0194 1 130 118 0465 150 0590

2 130 248 0975 263 1035

3 130 263 1035 279 1100

4 104 290 1140 305 1200

a Ampacities and DC resistance are based on 90 degC conductor temperature and a 30 degC ambient 1 b Ampacities are for raceways cable or earth (directly buried) 2 c For four-conductor cables where only three conductors are carrying current the ampacity for a three-conductor cable 3 may be used 4 d For ambient temperatures of other than 30 degC the correction factors under Table 310-15 (B)(16) of the NEC [B144] 5 should be used 6 7

Reactance values are not significant at power frequencies compared to resistance values for the 8 conductor sizes listed in the table and can be neglected 9




C311 DC resistance 1

The first step to determine the impedance is to calculate the dc resistance of the conductor 2 This may be found from manufacturerrsquos published information from tables such as the NEC 3 [B144] and NEMA WC 57ICEA S-73-532 [B140] or estimated using Equation (C3) 4 Equation (C3) is valid for a temperature range of approximately 100 degC When using tables it 5 may be necessary to adjust the values to account for a different operating temperature or cable 6 type 7

LSdc FFttA

R )(11

1211 Ωm (Ωft) (C4) 8

where 9

ρ1 is the resistivity of material at temperature t1 from Table C4 10 A is the conductor area in mm2 (cmil) 11 α1 is the temperature coefficient at temperature t1 from Table C4 12 FS is the stranding factor typically 102 for stranded conductor and 10 for solid 13

conductor 14 FL is the stranding lay factor typically 104 for stranded conductor and 10 for solid 15

conductor 16 t1 is the base temperature for other parameters 20 degC (68degF) 17 t2 is the cable operating temperature in degC (degF) 18

Table C4mdashParameters for DC resistance 19

Conductor material

Parameter Metric

(size in cmil) Metric

(size in mm2) Imperial

(size in cmil)

Copper (100 IACS)

ρ1 [t1 = 20 degC (68degF)]

34026 Ω cmilm 0017241 Ω mm2m 10371 Ω cmilft

α 1 000393 degC 000393 degC 000218degF Aluminum (61 IACS)

ρ1 [t1 = 20 degC (68degF)] 55781 Ω cmil m 0028265 Ω mm2m 17002 Ω cmilft

α 1 000403 degC 000403 degC 0 00224degF

20 Equation (C4) is used to calculate the resistance for a specific length of conductor as follows 21

61211 10)(1 LSdc FFtt

A

LR (Ω) (C5) 22

where the parameters are the same as Equation (C3) and Table C4 except 23 24

L is the conductor length in meters (feet) 25 26

In many cases there is a need to determine the size for a desired resistance Equation (C4) 27 may be rearranged to calculate the area and for convenience is given as the following 28 Equation (C5) 29




61211 10)(1 LS

dc

FFttR

LA mm2 (cmil) (C6) 1

C312 AC resistance 2

For ac circuits the conductor resistance increases due to several factors that include conductor 3 skin effect conductor proximity effect shield eddy currents shield circulating currents and 4 steel conduit losses The ac resistance is determined from the following Equation (C6) 5

)1( pscsecpcsdcac YYYYYRR (C7) 6

where 7

Rdc is the dc resistivity at reference temperature microΩm (microΩft) 8 Ycs is the conductor skin effect 9 Ycp is the conductor proximity effect 10 Yse is the shield eddy current 11 Ysc is the shield circulating current 12 Yp is the steel conduit losses 13 14

Note the factors used to calculate Rac are based on a per-unit resistance measured in micro-15 Ωmeter (micro-Ωfoot) 16

C3121 Conductor skin effectmdashYcs 17

The skin effect is caused by the varying current intensity that results in varying inductance 18 through a conductorrsquos cross section The inductance is maximum at the center of the conductor 19 and minimum on the surface Skin effect varies with temperature frequency stranding and 20 coating and can typically be ignored for cables 350 kcmil and smaller (less than 1 impact) 21 The skin effect factor is approximated using Equation (C7a) for Rdc in μΩm and Equation 22 (C7b) for Rdc in μΩft 23

2

2)(

2725

12413

283

11

SdcSdcS

dc

cs

kRkRk

RY (C8) 24

2

2)(

562

4

11

SdcSdcS

dc

cs

kRkRk

RY (C9) 25

where 26

kS is a constant from Table C5 27




Table C5mdash Recommended values for kS and kP 1

Conductor type Coating kS kP

Concentric round None tin or alloy 10 10 Compact round None 10 06

NOTEmdashThis table is a summary of Table II by Neher and McGrath [B86]

2

C3122 Conductor proximity effectmdashYcp 3

This effect is due to the force developed by currents flowing in the same direction in adjacent 4 conductors which concentrates electrons in the remote portions of a conductor Ycp increases 5 as spacing between conductors is decreased The factor is calculated using Equation (C8) 6 Equation (C9a) and Equation (C9b) 7

22

3120270)(

181)(

S

D

xpfS

DxpfY CC

cp (C10) 8

where 9

f(xp) is calculated according to Equation (C9a) for metric units or Equation (C9b) for 10 imperial units 11

kP is a constant from Table C5 12 DC is the diameter of the conductor in millimeters (inches) 13 S is the center-to-center spacing of conductors in millimeters (inches) 14 15

For metric units 16

2

2)(

2725

12413

283

11)(

pdcpdcp

dc

kRkRk

Rxpf (C11) 17

For imperial units 18

2

2)(

562

4

11)(

pdcpdcp

dc

kRkRk

Rxpf (C12) 19




C3123 Shield eddy currentsmdashYse 1

These losses are negligible except in power cables Losses are produced in cable shields due to 2 eddy currents produced in the shield as a function of conductor proximity Equations for 3 calculating these losses are given in the Neher and McGrath reference [B130] 4

C3124 Shield circulating currentsmdashYsc 5

This is significant for single conductor shielded cables spaced apart Circulating currents will 6 flow in cable shields when they are grounded at both ends This is accounted for by the factor 7 Ysc calculated using Equation (C 10) as follows 8

22

2

SM

M

dc

Ssc RX

X

R

RY (C13) 9

where 10

RS is the dc resistance of conductor sheath in μΩm (μΩft) 11 XM is the mutual inductance of shield and conductor in μΩm (μΩft) 12 13

The value of XM is dependent on the cable configuration Equation (C 1 1a) or Equation (C 1 14 1b) may be used for the typical situation where three single conductors are in the cradled 15 configuration in a duct for 60 Hz See Neher and McGrath [B130] for other situations 16

For metric units 17

SMM D

SX

2log6173 10 (μΩm) (C14) 18


SMM D

SX

2log9252 10 (μΩft) (C15) 20

where 21

S is the axial spacing of adjacent cables in millimeters (inches) 22 DSM is the mean diameter of the shield in millimeters (inches) 23 24

C3125 Losses in steel conduitsmdashYp 25

The magnetic field from current in cables causes hysteresis and eddy current losses in the steel 26 conduit This heats the conduit and raises the conductor temperature When all three phases are 27 in a conduit the magnetic field is significantly reduced due to phase cancellation For a single 28 conductor cable there is no cancellation and the heating is significant so this situation should 29




be avoided Loss factor may be calculated using Equation (C12a) for metric values and 1 Equation (C12b) for imperial values 2

For metric units 3

dc

PP R

DSY

890896 (C16) 4


dc

PP R

DSY

1150890 (C17) 6

where 7

S is the center-to-center line spacing between conductors in millimeters (inches) 8 DP is the inner diameter of conduit in millimeters (inches) 9

C313 Reactance 10

The reactance of a cable is a function of the spacing between conductors and the conductor 11 diameter Reactance is zero for dc circuits and insignificant for cable sizes less than 40 AWG 12 For a three-phase circuit the per-phase reactance is given by Equation (C13a) or Equation 13 (C13b) For a two-wire single- phase circuit the reactance will be twice that given by 14 Equation (C13a) or Equation (C13b) 15

For metric units 16

)05020

log46060(2 10

Cr

SfX (μΩmphase) (C18) 17


)01530

log14040(2 10

Cr

SfX (μΩftphase) (C19) 19

where 20

f is frequency in Hertz 21 Srsquo is equal to 3 CBA for the configurations shown in Figure C1 in millimeters 22

(inches) 23 rC is the radius of bare conductor in millimeters (inches) 24




A Equilateral TriangleA

A

C

B

B Right Triangle

C

AC Symmetrical Flat

C

B

C

AB

D Cradle

B

1 Figure C1mdash Common cable configurations 2

C32 Load 3

Information on the load being supplied is required Typically load current and power factor are 4 required Consideration should be given to whether the type of load is constant current 5 constant power or constant impedance The characteristics of the different load types are 6 summarized in Table C6 It is recommended that current be determined for the desired load 7 voltage If the current is available only for a specific voltage then the current may be 8 estimated using the formula in Table C6 9

Table C6mdash Load characteristics 10

Load type Examples Characteristics Estimating for different voltage

Constant power Motorsmdashfull load lighting

V uarr and I darr or V darr and I uarr

Inew = Iold (VoldVnew)

Constant impedance Motor starting heating

I varies with voltage Inew = Iold (VnewVold)

C4 Short-circuit capability 11

All cables should be checked to confirm they are capable of carrying the available fault 12 current The short- circuit rating of an insulated conductor is based on the maximum allowable 13 conductor temperature and insulation temperature 14

Conductor temperature is dependent on the current magnitude and duration Equation (C14) is 15 used to estimate conductor temperature and is valid only for short durations The maximum 16 recommended conductor temperature is 250 degC to prevent conductor annealing 17




o

o

FSC KT

KT

t

KAI

1

210

1 log (amperes) (C20) 1

where 2

ISC is the symmetrical short-circuit current in amperes 3 A is the conductor area in square millimeters (circular mils) 4 K0 is the inverse of material temperature coefficient at 0 degC per Table C7 5 K1 is the empirical material constant [B125] 6 tF is the duration of fault in seconds 7 T1 is the conductor temperature before the fault in degC 8 T2 is the conductor temperature after fault in degC 9

Table C7mdash Parameters for Equation (C20 and C21) 10

Conductor type K0 K1(imperial) K1(metric)

Copper 100 IACS 2345 00297 115678 Aluminum 61 IACS 2281 00125 4868502

11 In most cases the short-circuit current is known and the required conductor area requires to be 12 verified and determined Equation (C21) may be used for copper conductor type 13

01

0210

1 Tlog

KT

K

t

K

IA

F

SC mm2 (cmil) (C21) 14

The maximum insulation temperature is dependent on the material used Table C8 lists 15 maximum temperatures for common insulation materials Conductor temperature should be 16 limited to the insulation maximum temperature when the insulation maximum temperature is 17 less than 250 degC 18

Table C8mdash Insulation material temperature ratings 19

Insulation material Short-circuit temperature

rating ( degC)

XLPE and EPR 250 SR 300 Paper rubber varnish cambric 200

PE PVC 150

C5 Insulation 20

The selection of the cable insulation system also includes consideration of cost and 21 performance under normal and abnormal conditions Dielectric losses resistance to flame 22 propagation and gas generation when burned are the most common performance 23 considerations 24




C51 Voltage rating 1

The selection of the cable voltage rating is based on the service conditions of Annex B the 2 electrical circuit frequency phasing and grounding configuration and the steady-state and 3 transient conductor voltages with respect to ground and other energized conductors 4

A voltage rating has been assigned to each standard configuration of insulation material and 5 thickness in NEMA WC 57ICEA S-73-532 [B140] The selected voltage rating should result 6 in a cable insulation system that maintains the energized conductor voltage without 7 installation breakdown under normal operating conditions 8

C52 Thermal stability 9

The cable should maintain its required insulating properties when subjected to its rated thermal 10 limit (the combination of its maximum ambient temperature and its own generated heat) 11 during the service life 12

In some cable installations specifications may call for safe operation under high-temperature 13 conditions PE has a maximum service temperature of 80 degC and therefore it should be 14 replaced by other dielectrics where high-temperature operation is required Chlorosulfonated 15 PE (CSPE) is normally only rated up to 90 degC so better choices include XLPE or EPR 16 Silicone Rubber compound has been used in high-temperature cables (as high as 200 degC) or 17 where cable fire propagation is a consideration 18

Outdoor cables are typically rated 75 degC (eg insulated with heat resistant thermoplastic (type 19 THWN) Typical indoor cables are rated to 90 degC (eg type THHN) 20

C53 Moisture resistance 21

The cable should maintain its required insulating properties for its service life when installed 22 in wet locations especially underground 23

C54 Chemical resistance 24

The cable should maintain its required insulating properties when exposed to chemical 25 environments The cable manufacturer should be consulted for recommendations for specific 26 chemical requirements to which the cable may be exposed 27

C55 Flame propagation resistance 28

Cables installed in open or enclosed cable trays wireways or in other raceway systems where 29 flame propagation is of concern should pass the IEEE Std 1202 [B97] flame tests 30

C6 Jacket 31

The cable jacket or outer covering (if any) is selected to meet mechanical protection fire 32 resistance and environmental criteria or to provide a moisture barrier for the insulation 33 system 34




C61 Material 1

Jacket covering may consist of thermoset materials such as cross-linked chlorinated PE (CPE) 2 or chlorosulfonated polyethylene (CSPE) thermoplastic materials such as PVC andor metal 3 armor such as aluminum interlocked armor galvanized steel interlocked armor continuous 4 smooth or corrugated extruded aluminum armor or continuously welded smooth or corrugated 5 metallic armor with or without an overall nonmetallic sheath All thermoset and thermoplastic 6 jacket covering materials should be selected suitable for the conductor insulation temperature 7 rating and the environment in which they are to be installed Other acceptable jacket cover 8 materials include cross-linked polychloroprene (PCP) or cross- linked polyolefin (XLPO) In 9 the past lead sheaths were commonly used but are being phased out due to the adverse effects 10 of lead in the environment 11

C62 Markings 12

The jacket should be marked in a permanent fashion approximately every meter (few feet) 13 with the following recommended information consecutive length manufacturer year of 14 manufacture cable typesize and voltage 15

C7 Attenuation 16

Attenuation is a ratio comparing the power of the signal at the beginning and the end of a 17 communication cable Attenuation is measured in decibels per unit length and indicates the 18 loss of signal in the cable 19

C8 Cable capacitance 20

Cable capacitance is the ability of cable to store electrical charge Capacitance is measured in 21 picofarads per unit length High capacitance of communication cables slows down the signals 22 High capacitance of long control cables 60 m and more (200 ft) may lead to transient 23 overvoltages over circuit elements (relay coils contacts etc) during switching of the circuit 24 resulting in the damage to these elements 25




Annex D 1

(informative) 2

Design checklist for metallic communication cables entering a 3

substation 4

The following is a design checklist for metallic communications cable entering a substation 5

D1 Pre-design 6

Determine the equipment data transfer capacity and speed requirements (refer to IEEE Std 7 487 [B77] IEEE Std 4872 [B79] and IEEE Std 4873 [B80] for more information on 8 requirements) This information is usually obtained from the hardware or device 9 manufacturer 10

Determine the level of reliability or operations integrity required for the individual system 11 This information may be available from company policy documents or specific engineering 12 or design standards 13

D2 Communications requirements 14

Determine service types and service performance objective classifications per IEEE Std 487 15 [B77] 16

Establish the number of POTS (plain old telephone service) lines needed 17

mdash What is the number of voice circuits (normal and emergency) 18

mdash Are any extensions into the substation or switchyard required 19

mdash How many dial-up circuits are needed 20

a) Revenue meters 21

b) Transient fault recorder or protective relay interrogation 22

c) Security or fire alarms 23

mdash What dedicated telephone circuits are needed 24

a) Remote SCADA terminals 25

b) Protective relay tripping schemes 26

Is circuit-sharing equipment needed to limit the number of dial-up circuits 27




Define special requirements for coaxial cable [antennas or capacitive voltage transformers 1 (CVTs)] CAT-5 or other application specific requirements for particular hardware 2

D3 Cable protection requirements 3

Determine the GPR and fault current levels for the site This information is often obtained 4 through other departments (eg planning department) 5

Define the level of protection required for EMF interference (shielding) 6

What level of physical security is needed (eg should cabling from the ROW (right of way) 7 be enclosed in a rigid conduit in high risk areas) 8

Is the cable required to meet special application criteria (eg specific outer jacket design 9 due to corrosive atmosphere coal generation or industrial processes nearby) 10

D4 Site conditions 11

Can common routesruns be used (eg the communications circuits run isolated from but 12 in the same duct bank as station service power) 13

Are easements required for the telephone company or service provider 14

D5 Interface with telephone companyservice provider 15

Contact the telephone company or service provider with information from D 1 through 16 D4 17

Determine the number and types of circuits including service types and service 18 performance objective classifications for each circuit 19

Determine the number of circuit protective devices required for the determined GPR 20 Generally one protective device is required per circuit Note that short fiber optic links may 21 reduce or eliminate the need for GPR protective devices however the cost of fiber to hard 22 wirecopper multiplex equipment may be cost prohibitive for a small substation 23

Request the telephone companyservice provider installation costs for their equipment 24 services and interconnection at the nearest public right-of-way 25

Request the telephone companyservice provider describe the monthly costs for all leased or 26 rented circuits (POTS dedicated circuits high-speed interconnections) 27

Define the equipment to be provided by the telephone companyservice provider and by the 28 substation owner 29

Obtain the telephone companyservice providerrsquos construction requirements for cabling and 30 wallboard standards 31

mdash Is the owner required to provide a conduitraceway from the public ROW 32




mdash What type terminal blocks will be used 1

mdash Should the wallboard be ply-metal or another material 2

mdash What is needed to mount telephone companyservice provider terminal blocks 3

mdash Is a dedicated 120 V (ac) or 125 V (dc) power source needed 4

D6 Cost considerations 5

Prepare an economic cost summary including the following 6

mdash Installation labor costs for the telephone companyservice provider internal utility 7 company personnel and independent contractors 8

mdash Equipment costs for the hardware GPR circuit protection wallboard circuit or cable 9 runs past the telephone companyservice providerrsquos terminal blocks grounding etc 10

mdash Total monthly rental costs 11

Examine possible alternatives and their associated economics eg microwave link for 12 protective relay tripping schemes fiber optics for high-speed SCADA data transfer or relay 13 interrogation 14

D7 Communications system design 15

Develop a basis of design for the complete system There may be general utility 16 specifications and design criteria based upon experience and regional design criteria 17

Prepare a block diagram detailing the equipment locations (telephone board network 18 router etc) 19

Define the communication cable types and routes (eg twisted and shielded pairs CAT-5 20 coaxial cables multiple pair cables) 21

Review the final design with the substation owner and maintenance crews and the 22 telephone companyservice provider 23




Annex E 1

(normative) 2

Cable raceway design 3

This annex provides guidance for both a means of supporting cable runs between electrical 4 equipment and physical protection to the cables Raceway systems consist primarily of cable 5 tray and conduit 6

When designing the raceway for communications cable keep in mind that there may be 7 necessary requirements for separation of the communication cables from power and control 8 cables to reduce EMI for some communication cables Care should be taken in protecting 9 communication cables that are office rated and not rated for the substation environment They 10 generally do not have control cable grade jackets and if run in an exposed area should be 11 provided additional physical protection by the cable raceway design 12

Some communication cable may have a 600V jacket or may have a 300V jacket Cables with a 13 300V jacket are typically provided a mechanical separation from the power and control cables 14 rated at 600V This may require a dedicated raceway for communication cables 15

It may also be necessary to provide separation or protection of the communication cable to 16 prevent physical damage if the cable jacket is not suitable for the application 17

Adequate raceways should be provided throughout the cable path as a cable may traverse 18 different environments in the control building This is not as common as in a commercial 19 location but there may a separate communications room where the environmental 20 conditioning may be much different than the main control room Always design the raceway 21 and cable to the worst environmental conditions a cable will traverse 22

It is best to create a separate communication cable raceway that provides adequate separation 23 and protection from existing control and power cables Because communication cables are 24 used this cable tray may be much smaller than the main cable tray and simply hung below it 25 Use of fiberglass materials for the tray is acceptable 26

E1 Raceway fill and determining raceway sizes 27

Raceways should be adequately sized as determined by the maximum recommended 28 percentage fill of the raceway area Conduit fill is based on the following Equation (E1) 29

100_

_

areaRaceway

aareCableFill (E1) 30

Guidance for the maximum conduit fill is given in the NEC [B144] If the fill limitations and 31 cable area are known the raceway area can be calculated and an adequate size can be selected 32




E2 Conduit 1

E21 Conduit application 2

a) RMC or IMC zinc-coated conduit may be exposed in wet and dry locations 3 embedded in concrete and direct buried in soil If they are installed direct buried in 4 soil consideration should be given to the zinc coating having a limited life and 5 corrosion may be rapid after the zinc coating is consumed or damaged 6

b) When used in cinder fills the conduit should be protected by noncinder concrete at 7 least 5 cm (2 in) thick When used where excessive alkaline conditions exist the 8 conduit should be protected by a coat of bituminous paint or similar material PVC-9 coated steel conduit may be used in corrosive environments Plugs should be used to 10 seal spare conduits in wet locations 11

c) EPC-40 or EPC-80 conduit may be used exposed EPT and Type EB duct should be 12 encased in concrete and Type DB duct may be direct buried without concrete 13 encasement 14

d) Since ABS and PVC conduit may have different properties a review should be made 15 of their brittleness and impact strength characteristics Coefficient of expansion 16 should also be considered for outdoor applications Flammability of such conduits is 17 of particular concern in indoor exposed locations Burning or excessive heating of 18 PVC in the presence of moisture may result in the formation of hydrochloric acid 19 which can attack reinforcing steel deposit chlorides on stainless steel surfaces or 20 attack electrical contact surfaces The use of exposed PVC conduit indoors should 21 generally be avoided but may be considered for limited use in corrosive 22 environments 23

e) EMT may be used in dry accessible locations to perform the same functions as RMC 24 conduit except in areas that are judged to be hazardous Guidance in the 25 determination of hazardous areas is given in the NEC [B144] 26

f) Aluminum conduit (alloy 6061) plastic-coated steel conduit Type DB PVC or ABS 27 duct EPC-40 or EPC-80 PVC conduit and FRE conduit may be used in areas where 28 a highly corrosive environment may exist and for other applications where uncoated 29 steel conduit would not be suitable Aluminum conduit may be exposed in wet and 30 dry locations Aluminum conduit should not be embedded in concrete or direct buried 31 in soil unless coated (bitumastic compound etc) to prevent corrosion Aluminum 32 conduit may be used exposed or concealed where a strong magnetic field exists 33 however conduit supports should not form a magnetic circuit around the conduit if all 34 the cables of the electrical circuit are not in the same conduit 35

g) The cable system should be compatible with drainage systems for surface water oil 36 or other fluids but preferably should be installed to avoid accumulated fluids 37

h) The cable system should be capable of operating in conditions of water immersion 38 ambient temperature excursions and limited concentrations of chemicals Protection 39 should be provided against attack by insects rodents or other indigenous animals 40

i) Cable trays conduits and troughs are sometimes run above grade in substations 41 supported from equipment structures or specially designed ground-mounted 42 structures Troughs constructed of concrete or other material may be laid on the 43




grade Cost savings may be realized when comparing above-grade trays conduit and 1 troughs to similar below-grade systems 2

j) Care should be taken in routing above-grade systems to minimize interference with 3 traffic and equipment access and to avoid infringing on minimum electrical 4 clearances 5

k) Above-grade systems are more vulnerable to fires mechanical damage 6 environmental elements and seismic forces and offer greater susceptibility to 7 electrostatic and electromagnetic coupling than if the cables were below grade 8

n) Above-ground pull boxes are sometimes used for distribution panels and for common 9 connections such as current or voltage leads The judicious location of these boxes 10 may result in considerable savings If PVC conduit is used the thermal rating of the 11 PVC conduit should be considered and coordinated with the thermal rating and 12 quantity of enclosed cables The thermal rating of cables should be derated to the 13 thermal rating of the PVC conduit if it has a lower thermal rating 14

o) Electrical non-metallic tubing (ENT) may be used as an inner duct to protect and 15 segregate optical fibers and low-voltage communications cables in cable trench 16 systems cable trays and in rigid electrical conduits By convention blue colored 17 ENT is intended for branch and feeder circuits yellow colored ENT for 18 communications and red colored ENT for fire alarm and emergency systems 19

E22 Conduit system design 20

E221 Exposed conduit 21

a) Flexible conduit should be used between rigid conduit and equipment connection 22 boxes where vibration or settling is anticipated or where the use of rigid conduit is not 23 practical Liquid-tight flexible conduit is commonly used for this application Flexible 24 conduit length should be as short as practical but consistent with its own minimum 25 bending radius the minimum bending radius of the cable to be installed and the 26 relative motion expected between connection points A separate ground wire should 27 be installed if the flexible conduit is not part of the grounding and bonding system 28 See the NEC [B144] for additional guidance 29

b) Where it is possible for water or other liquids to enter conduits sloping of conduit 30 runs and drainage of low points should be provided 31

c) Electrical equipment enclosures should have conduit installed in a manner to prevent 32 the entrance of water and condensation Drain fittings and air vents in the equipment 33 enclosure should also be considered Expansion couplings should be installed in the 34 conduit run or at the enclosure to prevent damage caused by frost heaving or 35 expansion 36

d) The entire metallic conduit system whether rigid or flexible should be electrically 37 continuous and grounded 38

e) When installed in conduit of magnetic material all phases of three-phase ac circuits 39 and both legs of single-phase ac circuits should be installed in the same conduit or 40 sleeve 41




f) All conduit systems should have suitable pull points (pull boxes manholes etc) to 1 avoid over-tensioning the cable during installation 2

E222 Embedded conduits and manholes 3

a) Spacing of embedded conduits should permit fittings to be installed 4

b) Conduit in duct runs containing one phase of a three-phase power circuit or one leg of 5 a single- phase power circuit should not be supported by reinforcing steel forming 6 closed magnetic paths around individual conduits Reinforcing steel in the manhole 7 walls should not form closed loops around individual nonmetallic conduit entering 8 the manhole Nonmetallic spacers should be used 9

c) Concrete curbs or other means of protection should be provided where other than 10 RMC conduits turn upward out of floor slabs 11

d) The lower surface of concrete-encased duct banks should be located below the frost 12 line When this is not practical lean concrete or porous fill can be used between the 13 frost line and the duct bank 14

e) Concrete-encased duct banks should be adequately reinforced under roads and in 15 areas where heavy equipment may be moved over the duct bank 16

f) Direct buried nonmetallic conduits should not be installed under roadways or in areas 17 where heavy equipment may be moved over them unless the conduits are made from 18 resilient compounds suitable for this service or are protected structurally 19

g) Conduits in duct banks should be sloped downward toward manholes or drain points 20

h) Duct lengths should not exceed those which will develop pulling tensions or sidewall 21 pressures in excess of those allowed by the cable manufacturerrsquos recommendations 22

i) Manholes should be oriented to minimize bends in duct banks 23

j) Manholes should have a sump if necessary to facilitate the use of a pump 24

k) Manholes should be provided with the means for attachment of cable-pulling devices 25 to facilitate pulling cables out of conduits in a straight line 26

l) Provisions should be made to facilitate racking of cables along the walls of the 27 manhole 28

m) Exposed metal in manholes such as conduits racks and ladders should be grounded 29

n) End bells should be provided where conduits enter manholes or building walls 30

o) Manholes and manhole openings should be sized so that the cable manufacturerrsquos 31 minimum allowable cable bending radii are not violated 32

p) When installed in conduit of magnetic material all phases of three-phase ac circuits 33 and both legs of single-phase ac circuits should be installed in the same conduit or 34 sleeve 35




E23 Conduit installation 1

a) Supports of exposed conduits should follow industry standards See the NEC [B144] 2 for additional information 3

b) When embedded in concrete installed indoors in wet areas and placed in all outdoor 4 locations threaded conduit joints and connections should be made watertight and 5 rustproof by means of the application of a conductive thread compound which will 6 not insulate the joint Each threaded joint should be cleaned to remove all of the 7 cutting oil before the compound is applied The compound should be applied only to 8 the male conduit threads to prevent obstruction 9

c) Running threads should not be utilized and welding of conduits should not be done 10

d) Field bends should not be of lesser radius than suggested by the NEC [B144] and 11 should show no appreciable flattening of the conduit 12

e) Large radius bends should be used to reduce the cable sidewall pressure during cable 13 installation and in conduit runs when the bending radius of the cable to be contained 14 in the conduit exceeds the radius of standard bends 15

f) Conduits installed in concrete should have their ends plugged or capped before the 16 concrete is poured 17

g) All conduit interiors should be free of burrs and should be cleaned after installation 18

h) Exposed conduit should be marked in a distinct permanent manner at each end and at 19 points of entry to and exit from enclosed areas 20

i) Flexible conduit connections should be used for all motor terminal boxes and other 21 equipment which is subject to vibration The connections should be of minimum 22 lengths and should employ at least the minimum bending radii established by the 23 cable manufacturer 24

j) Conduit should not be installed in proximity to hot pipes or other heat sources 25

k) Proper fittings should be used at conduit ends to prevent cable damage 26

l) Conduits should be installed so as to prevent damage to the cable system from the 27 movement of vehicles and equipment 28

m) Conduit entrances to control buildings should be provided with barriers against 29 rodents and fire 30

E3 Cable tray 31

This clause provides guidance for the installation of cables that installed in cable tray Typical 32 cable tray configurations are shown in Figure E1 33




1 Figure E1mdashTypical cable tray configurations 2

E31 Tray design 3

a) Cable tray design should be based upon the required loading and the maximum 4 spacing between supports Loading calculations should include the static weight of 5 cables and a concentrated load of 890 N (200 lb) at midspan The tray load factor 6 (safety factor) should be at least 15 based on collapse of the tray when supported as a 7 simple beam Refer to NEMA VE 1 [B137] for metallic tray or NEMA FG 1 [B133] 8 for fiberglass tray 9

b) When the ladder-type tray is specified rung spacing should be a nominal 23 cm (9 10 in) For horizontal elbows rung spacing should be maintained at the center line 11

c) Design should minimize the possibility of the accumulation of fluids and debris on 12 covers or in trays 13

E32 Tray system design 14

a) In general vertical spacing for cable trays should be 30 cm (12 in) measured from 15 the bottom of the upper tray to the top of the lower tray A minimum clearance of 23 16 cm (9 in) should be maintained between the top of a tray and beams piping etc to 17 facilitate installation of cables in the tray 18

b) Cables installed in stacked cable trays should be arranged by descending voltage 19 levels with the higher voltage at the top 20

c) When stacking trays the structural integrity of components and the pullout values of 21 support anchors and attachments should be verified 22

d) Provisions for horizontal and vertical separation of redundant system circuits are 23 described in Annex I 24




e) A separate tray system may be utilized for fiber optic cables The fiber optic tray may 1 use color-coded non-metallic material 2

E33 Tray application 3

The materials from which the tray is fabricated include aluminum galvanized steel and 4 fiberglass In selecting material for trays the following should be considered 5

a) A galvanized tray installed outdoors will corrode in locations such as near the ocean 6 or immediately adjacent to a cooling tower where the tray is continuously wetted by 7 chemically treated water If an aluminum tray is used for such applications a 8 corrosive-resistant type should be specified Special coatings for a steel tray may also 9 serve as satisfactory protection against corrosion The use of a nonmetallic tray 10 should also be considered for such applications 11

b) For cable trays and tray supports located outdoors the effect of the elements on both 12 the structure and the trays should be considered Ice snow and wind loadings should 13 be added to loads described in item a) of E31 Aluminum alloys 6061-T6 6063-T6 14 and 5052-M34 are acceptable with careful recognition of the differences in strength 15 Mill-galvanized steel should normally be used only for indoor applications in non-16 corrosive environments Hot-dipped galvanized-after-fabrication steel should be used 17 for outdoor and damp locations 18

c) When the galvanized surface on the steel tray is broken the area should be coated to 19 protect against corrosion 20

d) Consideration should be given to the relative structural integrity of aluminum versus 21 steel tray during a fire 22

E34 Tray load capacity 23

a) The quantity of cable installed in any tray may be limited by the structural capacity of 24 the tray and its supports Tray load capacity is defined as the allowable weight of 25 wires and cables carried by the tray This value is independent of the dead load of the 26 tray system In addition to and concurrent with the tray load capacity and the dead 27 load of the tray system any tray should neither fail nor be permanently distorted by a 28 concentrated load of 890 N (200 lb) at midspan at the center line of the tray or on 29 either side rail 30

b) A percentage fill limit is needed for randomly filled trays because cables are not laid 31 in neat rows and secured in place This results in cable crossing and void areas which 32 take up much of the tray cross-sectional area Generally a 30 to 40 fill for power 33 and control cables and a 40 to 50 fill for instrumentation cables is suggested This 34 will result in a tray loading in which no cables will be installed above the top of the 35 side rails of the cable tray except as necessary at intersections and where cables enter 36 or exit the cable tray systems 37

c) The quantity of cables in any tray may be limited by the capacity of the cables at the 38 bottom of the tray in order to withstand the bearing load imposed by cables located 39 adjacent and above This restraint is generally applicable to instrumentation cables 40 but may also apply to power and control cables 41




E4 Cable tray installation 1

E41 Dropouts 2

a) Drop-out fittings should be provided when it is required to maintain the minimum 3 cable training radius 4

b) Where conduit is attached to the tray to carry exiting cable the conduit should be 5 rigidly clamped to the side rail When conduit is rigidly clamped consideration 6 should be given to the forces at the connection during dynamic (seismic) loading of 7 the tray and conduit system Conduit connections through the tray bottom or side rail 8 should be avoided 9

E42 Covers 10

a) Horizontal trays exposed to falling objects or to the accumulation of debris should 11 have covers 12

b) Covers should be provided on exposed vertical tray risers at floor levels and other 13 locations where possible physical damage to the cables could occur 14

c) Where covers are used on trays containing power cables consideration should be 15 given to ventilation requirements and cable ampacity derating 16

E43 Grounding 17

Cable tray systems should be electrically continuous and solidly grounded When cable trays 18 are used as raceways for solidly grounded or low-impedance grounded power systems 19 consideration should be given to the tray system ampacity as a conductor Inadequate ampacity 20 or discontinuities in the tray system may require that a ground conductor be attached to and 21 run parallel with the tray or that a ground strap be added across the discontinuities or 22 expansion fittings The ground conductor may be bare coated or insulated depending upon 23 metallic compatibility 24

E44 Identification 25

Cable tray sections should be permanently identified with the tray section number as required 26 by the drawings or construction specifications 27

E45 Supports 28

The type and spacing of cable tray supports will depend on the loads Tray sections should be 29 supported near section ends and at fittings such as tees crosses and elbows Refer to NEMA 30 VE 1 [B137] 31




E46 Location 1

Trays should not be installed in proximity to heating pipes and other heat sources 2

E5 Wireways 3

Wireways are generally sheet metal troughs with hinged or removable covers for housing and 4 protecting wires and cables Wireways are for exposed installations only and should not be 5 used in hazardous areas Guidance in the determination of hazardous areas is given in the NEC 6 [B144] Consideration should be given to the wireway material where corrosive vapors exist 7 In outdoor locations wireways should be of raintight construction The sum of the cross-8 sectional areas of all conductors should not exceed 40 of the interior cross-sectional area of 9 the wireway Taps from wireways should be made with rigid intermediate metal electrical 10 metallic tubing flexible-metal conduit or armored cable 11

E6 Direct burial tunnels and trenches 12

This clause provides guidance for the installation of cables that are direct buried or installed in 13 permanent tunnels or trenches 14

E61 Direct burial 15

Direct burial of cables is a method whereby cables are laid in an excavation in the earth with 16 cables branching off to various pieces of equipment The excavation is then backfilled 17

A layer of sand is usually installed below and above the cables to prevent mechanical damage 18 Care should be exercised in backfilling to avoid large or sharp rocks cinders slag or other 19 harmful materials 20

A warning system to prevent accidental damage during excavation is advisable Several 21 methods used are treated wood planks a thin layer of colored lean concrete a layer of sand 22 strips of plastic and markers above ground Untreated wood planks may attract termites and 23 overtreatment may result in leaching of chemicals harmful to the cables 24

Spare cables or ducts may be installed before backfilling 25

This system has low initial cost but does not lend itself to changes or additions and provides 26 limited protection against the environment Damage to cables is more difficult to locate and 27 repair in a direct burial system than in a permanent trench system 28

E62 Cable tunnels 29

Walk-through cable tunnels can be used where there will be a large number of cables 30

This system has the advantages of minimum interference to traffic and drainage good physical 31 protection ease of adding cables shielding effect of the ground mat and the capacity for a 32 large number of cables 33




Disadvantages include high initial cost and danger that fire could propagate between cable 1 trays and along the length of the tunnel Fire hazards may be reduced by providing fire stops 2

E63 Permanent trenches 3

Trench systems consist of main runs located to bring large groups of cables through the centers 4 of equipment groups with short runs of conduit smaller trenches or direct-burial cable 5 branching off to individual pieces of equipment Typical trench configurations are shown in 6 Figure E2 7

8 Figure E2mdashTypical trench configurations 9

Duct entrances may be made at the bottom of open-bottom trenches or through knockouts in 10 the sides of solid trenches 11

Trenches may be made of cast-in-place concrete fiber pipes coated with bitumastic or precast 12 material 13

Where trenches interfere with traffic in the substation vehicle crossoversmdashpermanent or 14 temporarymdashmay be provided as needed Warning posts or signs should be used to warn 15 vehicular traffic of the presence of trenches 16

The trenches may interfere with surface drainage and can be sloped to storm sewers sump 17 pits or French drains Open-bottom trenches may dissipate drainage water but are vulnerable 18 to rodents A layer of sand applied around the cables in the trench may protect the cables from 19 damage by rodents Trenches at cable entrances into control buildings should be sloped away 20 from the building for drainage purposes and be equipped with barriers to prevent rodents from 21 entering the control building 22

When selecting the route or layout of the permanent cable trench considerations should be 23 taken to prevent the spread of cable or oil fires within the cable trench For more fire 24 protection information reference IEEE 979 [B92] 25




The tops of the trench walls may be used to support hangers for grounded shield conductors 1 The covers of trenches may be used for walkways Consideration should be given to grounding 2 metal walkways and also to providing safety clearance above raised walkways Added concern 3 should be given to the flammability of wood 4

E631 Floor trenches 5

Trenches cast into concrete floors may be extensive with trenches run wherever required or a 6 few trenches may be run under the switchboards with conduits branching to various pieces of 7 equipment 8

Removable covers may be made of metal plywood or other materials Nonmetallic cover 9 materials should be fire retardant Trenches cast into concrete floors should be covered It 10 should be noted that metal covers in the rear of switchboards present a handling hazard and 11 nonmetallic fire-retardant material should be used 12

Where cables pass through holes cut in covers for example in rear or inside of switchboards 13 the edges should be covered to prevent cable damage from sharp edges 14

E632 Raised floors 15

Raised floors provide maximum flexibility for additions or changes Entrance from the outside 16 into the raised floor system may be made at any point along the control building wall 17

Use of a fire protection system under the floor should be considered 18




Annex F 1

(normative) 2

Routing 3

Ethernet cables may be routed per TIA-1005 [B8] with the understanding that a substationrsquos 4 telecommunication spaces are not as widely varied as an industrial space and commercial 5 space The number of moves adds and changes are rare in the substation environment 6 resulting in the limited application of patch cables between Ethernet switches and IEDs The 7 addition of patch panels for Ethernet represents another potential failure point that may 8 decrease the reliability of the communications path by introducing other elements with a finite 9 reliability in an environment where communication failures may not be tolerated Similar 10 routing could be applied to other communications cable such as serial coaxial and fiber 11 cables 12

Cabling requirements (permanent link and channel) for category 3 category 5e category 6 and 13 category 6A 100-Ω balanced twisted-pair cabling are specified in ANSITIA-568-C2 [B4] 14 See ANSITIA-568-C2 for component transmission performance and ANSITIA-1152 for 15 associated field test equipment requirements 16

Lack of separation between power and telecommunications cabling may have transmission 17 performance implications Refer to requirements in 522 of TIA-1005 [B8] for Ethernet 18 copper cable pathway separation from EMI sources 19

Routing for redundancy or diversity is addressed in Annex I 20

F1 Length 21

Cable routing in the switchyard should provide the shortest possible runs where practical to 22 minimize voltage drops in the auxiliary power and control cables and loss of signal in a 23 communication cable etc as well as to reduce amount of cable required 24

F2 Turns 25

Layouts should be designed to avoid sharp corners and provide adequate space to meet 26 bending radius and cable pull requirements for specific types of cables Layouts should 27 consider future installation of foundations and cable routings It may be beneficial to have 28 cable layouts perpendicular or parallel to the main buses to avoid crossing at angles and to 29 maximize routing space 30

F3 Physical location and grouping 31

Physical separation of redundant cable systems generally utilize separate raceway systems or 32 barriers within raceways such as cable trays and cable trenches to isolate wiring of normal 33 power supplies primary relaying and control and the primary battery system from the wiring 34 of backup power supplies backup or secondary relaying and control and the secondary battery 35 system 36




Physical separation between a transient source and other cables including communication 1 cables is an effective means of transient control Because mutual capacitance and mutual 2 inductance are greatly influenced by circuit spacing small increases in distance may produce 3 substantial decreases in interaction between circuits (Dietrich et al [B21])Ground conductors 4 on both sides of the cable trench or a single conductor on the EHV bus side of the cable trench 5 can reduce induced transient voltage A shield conductor above conduits directly buried in the 6 ground may also reduce transient voltages Maximum practical separation between control 7 cables and EHV buses that are in parallel should be maintained Control cables with overall 8 shield grounded at both ends can help reduce transient voltage (ldquoInduced transient voltage 9 reductions in Bonneville Power Administration 500 kV substationrdquo [B36] ldquoProtection against 10 transientsrdquo [B148] Dietrich et al [B21]) 11

NOTEmdashTests indicate that in some cases nonshielded control cables may be used without paralleling ground cables 12 when they are parallel and are located at a distance greater than 15 m (50 ft) from or are perpendicular to a typical 345 13 kV bus (Garton and Stolt [B33]) 14

Great care should be exercised in routing cables through areas enclosed by back-to-back 15 switching capacitor banks where potentially high ground grid current (either power-frequency 16 or high-frequency currents) exists (ldquoInduced transient voltage reductions in Bonneville Power 17 Administration 500 kV substationrdquo [B36]) When practical control cables may be installed 18 below the main ground grid andor routed perpendicular to the EHV busses All cables from 19 the same equipment should be close together particularly to the first manhole or equivalent in 20 the switchyard (ldquoInduced transient voltage reductions in Bonneville Power Administration 500 21 kV substationrdquo [B36]) 22

Cables connected to equipment having comparable sensitivities should be grouped together 23 and then the maximum separation should be maintained between groups High-voltage cables 24 should not be in duct runs or trenches with control cables (Dietrich et al [B21] ldquoInduced 25 transient voltage reductions in Bonneville Power Administration 500 kV substationrdquo [B36] 26 ldquoProtection against transientsrdquo [B148]) 27

F4 Fire impact 28

For cases where possible catastrophic failure of equipment may lead to fire consider the 29 routing of critical cables to help reduce coincidental fire damage This affects the proximity 30 routing of trenches and the use of radial raceways rather than a grouped raceway 31

Cable trenches may be installed at a higher elevation than the surrounding area to limit the 32 possibility of oil or flaming oil from entering the cable trench Stacking cable trays with 33 primary and backup systems should be avoided to reduce the possibility of a fire damaging 34 both systems 35




Annex G 1

(normative) 2

Transient protection of instrumentation control and power cable 3

This annex provides information on the origin of transients in substations and guidance for 4 cable shielding and shield grounding for medium-voltage power instrumentation control 5 coaxial and triaxial cable systems 6

G1 Origin of transients in substations 7

This clause provides information on the origins of EMI voltages in the substation environment 8

G11 Switching arcs 9

One of the most frequently encountered sources of EMI in high-voltage yards (230 kV and 10 higher voltage) is during energization or de-energization of the bus by an air-break switch or a 11 circuit switcher Typically during this type of switching intense and repeated sparkovers occur 12 across the gap between the moving arms At each sparkover oscillatory transient currents with 13 200 A to 1500 A crests circulate in buses in the ground grid in bushing capacitances in 14 capacitive voltage transformers (CVTs) and in other apparatus with significant capacitances to 15 ground The number of individual transients in an opening or closing operation can vary from 16 5 000 to 10 000 (Gavazza and Wiggins [B34]) 17

The transients are coupled to the low-voltage wiring by three basic modes These are as 18 follows 19

a) Radiated magnetic or electric field coupling 20

b) Conducted coupling through stray capacitances such as those associated with 21

bushings CTs and CVTs 22

c) Conductive voltage gradients across ground grid conductors 23

G12 Capacitor bank switching 24

Switching of grounded capacitance banks introduces transients in overhead buses and in the 25 ground grid In many instances design requirements dictate installation of several banks in 26 parallel This necessitates ldquoback-to-backrdquo switching of two or more banks The ldquoback-to-backrdquo 27 switching of large capacitor banks by a circuit switcher can produce an intense transient 28 electromagnetic field in the vicinity of the banks These high-energy transients typically 29 couple to cables through the overhead bus and the ground grid conductors 30

In many respects these switching transients are similar to those generated by an air break 31 switch energizing or de-energizing a section of bus These transients differ from the other 32 transients in regards to the magnitude of the transient current and its associated frequencies 33 While the current magnitudes range from 5 000 A to 20 000 A the frequency components 34




contain four widely separated ranges listed as follows (ldquoShunt capacitor switching EMI 1 voltages their reduction in Bonneville Power Administration substationsrdquo [B37]) 2

a) Frequencies in the megahertz range due to distributed parameters of the buses and the 3 lines 4

b) Medium frequency oscillations occurring between the two banks contain the 5 frequency range of 5 kHz to 15 kHz (these frequencies are dominant in back-to-back 6 switching) 7

c) Low-frequency oscillations occurring between the capacitor banks and the power-8 frequency source contain the frequency range of 400 Hz to 600 Hz (these frequencies 9 are dominant in the case of a bank switched against the bus) 10

d) 50 Hz or 60 Hz source frequency 11

The modes by which the voltage and current transients are coupled to the cables are basically 12 the same as those listed in G11 13

G13 Lightning 14

Lightning is another source that can cause intense EMI in low-voltage circuits In general 15 lightning is a high-energy unidirectional surge with a steep wave front In the frequency 16 domain a broad frequency band represents this type of surge The frequency range covered by 17 this spectrum is from dc to megahertz 18

The following are some ways lightning can cause over-voltages on cables 19

a) Direct strike to the mast or overhead shield wire in the substation 20

b) Lightning entering the substation through overhead transmission or distribution lines 21

c) Induced lightning transients due to strikes in the vicinity of the substation 22

The surge current flows into earth via ground grid conductors and through the multi-grounded 23 shield and neutral network There are two primary modes of coupling to the cables The 24 inductive coupling is due to voltage and current waves traveling in the overhead shield wires 25 in the buses and in the ground grid conductors The conductive coupling consists of voltage 26 gradients along the ground grid conductors due to flow of transient current 27

In a substation a transient grid potential rise (TGPR) with respect to a remote ground may also 28 exist This transient voltage most likely will couple to telecommunication lines entering the 29 substation from remote locations If proper isolation is not provided this voltage may cause 30 damage to the telecommunication equipment in the substation The magnitude of TGPR is 31 proportional to the peak magnitude and rate of rise of the stroke current and the surge 32 impedance of the grounding system 33

G14 Power-frequency faults (50 Hz or 60 Hz) 34

Electronic devices are vulnerable to damage if a large magnitude of power-frequency fault 35 current flows in the ground grid conductors due to a phase-to-ground fault Erroneous 36 operations of relay circuits are known to occur under these conditions 37




There are two basic modes of coupling which exist when a phase-to-ground fault occurs in a 1 substation The induced voltage on the cable due to the fault current flowing in ground 2 conductors is one mode of coupling More dominant coupling however is the conductive 3 voltage gradient along the ground grid conductors resulting from the current flow 4

Coupling due to GPR with respect to remote ground may exist on telecommunication circuits 5 entering the substation The GPR magnitude will be proportional to the fault current entering 6 the earth from the ground grid conductors and the ground grid resistance to remote ground 7 (IEEE Std 487 [B77] EPRI EL-5990-SR [B29] Perfecky and Tibensky [B147]) Sometimes 8 the telecommunication circuit leaving the substation parallels the power line In this case the 9 total coupling would be a net result of GPR and the induced voltage due to fault current 10 flowing in that power line 11

G15 Sources within cable circuits 12

During interruption of dc current in an inductor such as a relay coil a large induced voltage 13 may appear across the inductor due to Faradayrsquos Law (V =L didt) (ldquoTransient pickup in 500 14 kV control circuitsrdquo [B161]) Normally the maximum voltage will exist at the instant of 15 interruption The surge voltage magnitude is proportional to the impedance of the supply 16 circuit and the speed of interruption Voltages in excess of 10 kV have been observed across a 17 125 V coil in laboratory tests but 25 kV with 5 micros rise time is a typical value to be expected 18 Once produced these powerful fast rising high-voltage pulses are conducted throughout the 19 supply circuit and can affect adjacent circuits where capacitive coupling exists Full battery 20 voltage appears initially across the impedance of the adjacent circuit and then decays 21 exponentially in accordance with the resistance-capacitance time constant of the circuit 22 (ldquoProtection against transientsrdquo [B148]) 23

The extensive use of surge capacitors on solid-state equipment and the longer control cable 24 runs associated with EHV stations have substantially increased the capacitance between 25 control wiring and ground Inadvertent momentary grounds on control wiring cause a 26 discharge or a redistribution of charge on this capacitance Although this seldom causes 27 failure the equipment may malfunction 28

Saturation of CTs by high-magnitude fault currents including the dc offset can result in the 29 induction of high voltages in the secondary windings This phenomenon is repeated for each 30 transition from saturation in one direction to saturation in the other The voltage appearing in 31 the secondary consists of high- magnitude spikes with alternating polarity persisting for an 32 interval of a few milliseconds every half cycle (ldquoProtection against transientsrdquo [B148]) 33

G2 Protection measuresmdashGeneral considerations 34

There are two types of voltages that develop at cable terminations when the cable is exposed to 35 high energy transients At this point it is important to visualize two loop areas enclosed by 36 cable pair including its terminal equipment The loop area enclosed between the conductors of 37 a pair is relatively small and typically links a fraction of disturbing field The voltage so 38 developed across the conductors is called differential mode voltage In general the differential 39 mode voltages are too small to cause any equipment damage However the loop currents that 40 result from these voltages sometimes are responsible for erroneous operations of protective 41 devices Using a twisted pair cable may eliminate this problem altogether Responsible for 42 most damages are the common mode voltages at the terminals The common mode voltage 43 results due to the loop formed between the pair and ground grid conductors A strong coupling 44 from disturbing fields usually exists due to the large area enclosed by this loop The common 45




mode voltage is defined as the voltage between the cable conductors and the ground The main 1 objective of conductive shields is to minimize or preferably eliminate these voltages and 2 resulting currents 3

Common and differential mode voltages at cable terminations cannot be completely 4 eliminated but can be limited in magnitude Since transient voltages can be coupled to the 5 cables due to their exposure in the substation yard the need for providing protection to help 6 reduce these coupled transients should be considered by the utility engineers On the other 7 hand designing the electronic equipment to withstand certain transient levels as specified by 8 the standards (EPRI EL-2982 Project 1359-2 [B28] IEC 61000-4-1 [B59] IEC 61000-4-4 9 [B60] IEC 61000-4-5 [B61] IEEE Std C37901 [B107]) and providing appropriate surge 10 suppressors at the terminals is traditionally a manufacturing function Discussion on terminal 11 protection is beyond the scope of this guide The following protection measures are discussed 12 in this clause 13

a) Cable routing 14

b) Shield and shield grounding 15

c) Substation grounding and parallel ground conductors 16

G21 Cable routing 17

Radial arrangement of instrumentation and control circuits will reduce transient voltages by 18 minimizing the loop sizes between the cable pairs running to the same apparatus This is 19 effectively accomplished by 20

mdash Installing the cable pairs running to the same apparatus in one trench or conduit 21

mdash Avoiding the loop formed due to cables running from one apparatus to another 22 apparatus and returning by different route 23

mdash Running the circuits in a tree fashion with a separate branch to each equipment such 24 as breaker transformer etc 25

The trench or conduit carrying the cables should not run parallel to the overhead HV buses In 26 cases where this is unavoidable provide as much separation distance as practically feasible to 27 reduce the capacitive coupling from the buses 28

A substation may have underground HV circuit running across the yard A power-frequency 29 fault current in the HV cable may cause a transient in control cables laid in parallel and in 30 proximity due to magnetic coupling Avoiding the parallel run or providing a larger separation 31 distance can reduce the transient overvoltage 32

G22 Shield and shield grounding 33

In general shielded cables regardless of ground connections at the ends provide immunity 34 from magnetically coupled voltages This protection is a result of eddy currents set up by the 35 external magnetic field in the coaxial shield The eddy currents in the shield then produce the 36 opposing field reducing the field coupled to the signal conductors Due to its high conductivity 37 and immunity from saturation a nonmagnetic (nonferrous) material is typically used for 38 shielding purpose A typical nonmagnetic material used for shielding purpose may include 39




copper aluminum bronze or lead The shielding efficiency of a nonmagnetic eddy-current 1 shield is directly proportional to the following (Buckingham and Gooding [B18]) 2

a) Shield diameter 3

b) Shield thickness 4

c) Conductivity (or 1resistivity) 5

d) Frequency 6

e) Permeability 7

The lower the shield impedance the greater its transient voltage cancellation efficiency 8 Generally lower surge impedance permits larger induced transient currents to flow in the 9 shield (ldquoMethods of reducing transient overvoltages in substation control cablesrdquo [B128]) 10 Table G1 lists the conductivity data of four commonly used shielding materials 11

Table G1mdash Conductivity data for four commonly used shielding materials 12

Copper Aluminum Bronzea Lead

Conductivity mho-meter 58 354 255 45 a90 copper 10 zinc 13

The protection provided by an ungrounded shield is not adequate in high-voltage and high 14 current noise environments of substations For example an ungrounded shield cannot protect 15 the cable from capacitively coupled voltages Typically 1 of the transient voltage on a high-16 voltage bus is coupled to a cable with ungrounded shield This can amount to a common mode 17 voltage of several thousand volts With the shield grounded at one end the capacitively-18 coupled electric field is prevented from terminating on the cable resulting in virtually no 19 differential or common mode voltage 20

Grounding the shield at one end effectively protects the equipment at that end but equipment 21 connected at the ungrounded end remains unprotected In some instances shield-to-ground and 22 conductor-to-ground voltages may even increase at the ungrounded end (Dietrich et al [B21] 23 ldquoMethods of reducing transient overvoltages in substation control cablesrdquo [B128]) For 24 providing protection at both ends of the cable the shield should be grounded at both ends 25 (Garton and Stolt [B33]) Grounding the shield at both ends links a minimum external field 26 due to reduced loop area enclosed by the cable pairs and shield conductor Several field and 27 laboratory tests show that grounding the shield at both ends reduce the common mode voltage 28 between 50 and 200 times (ldquoControl circuit transients in electric power systemsrdquo [B122] 29 ldquoControl circuit transientsrdquo [B123]) 30

The shield conductors are not rated to carry power-frequency fault currents For this reason 31 one or more ground conductors should be installed in the proximity of the cable circuits where 32 shield conductors are grounded at both ends 33

In the case of an unbalanced circuit (equipment circuit is not grounded in the electrical 34 middle) a differential voltage across the pair develops if the impedance on each side of the 35 signal ground in the terminal equipment is different This differential voltage will be 36 proportional to the current due to the common mode voltage during the transient Depending 37 on the unbalance at the terminal grounding the shield at both ends may increase this 38 differential voltage For a given transient this differential voltage can be reduced by grounding 39 the signal circuit nearly in the electrical middle (IEEE Std 1050 [B94]) 40




It is necessary to keep the shield in a cable intact as a broken or separated shield can greatly 1 reduce the shield efficiency Also in a substation where there may at times be large fault 2 currents a problem arises if the shield is grounded at two widely separated locations The 3 power-frequency potential difference on the ground grid may cause enough current to flow in 4 the shield to cause damage Installation of one or more 20 or 40 AWG bare copper 5 conductors in parallel would significantly reduce the current flow in the shield 6

G23 Substation grounding and parallel ground conductors 7

The design of ground grid systems the methods of grounding equipment and shielding of 8 cable circuits have a large influence on EMI voltages that appear at the terminals 9

The ground grid even when designed with a very low resistance cannot be considered as an 10 equal-voltage surface Substantial grid voltage differences may exist particularly in a large 11 substation yard Several factors influence voltage gradients across the ground grid conductors 12 These factors include the impedance of grid conductors grid geometry distribution of ground 13 currents (see IEEE Std 80 [B69]) earth resistivity (see ldquoTransient pickup in 500 kV control 14 circuitsrdquo [B161] and IEEE Std 81 [B70]) and magnitude and frequency of the transient 15 (Gillies and Ramberg [B35]) 16

Since it is impractical to eliminate voltage gradients along ground grid conductors additional 17 measures are necessary to reduce their influence on the cables Typically this measure consists 18 of installing low- impedance ground conductors in proximity and parallel to the affected 19 circuits These conductors carry currents proportional to voltage gradients along the grid 20 conductors and serve several purposes The flow of currents in these conductors induces a 21 counter voltage in the control circuits and also reduces the conductive voltage difference 22 between the two terminals In the case of a power-frequency fault these ground conductors 23 carry most of the fault currents protecting the shield conductors grounded at both ends 24

The following are some guidelines to maximize protection from parallel ground conductors 25

a) Ground conductors in trenches 26

1) Install conductors with sufficient conductivity to carry maximum available 27 fault current in the substation and having adequate mechanical strength A 28 typical installation uses 20 or 40 bare copper conductor 29

2) Attach a minimum of two ground conductors on the topside of each trench If 30 required additional ground conductors can be placed outside but in 31 proximity of the trench This places the ground conductors between the 32 radiated EMI source and the cables (ldquoTransient pickup in 500 kV control 33 circuitsrdquo [B161]) 34

3) Connect ground conductors with ground grid mesh conductors at several 35 locations 36

b) Ground conductors parallel to duct banks 37

1) Place a minimum of two ground conductors at the top edges of the duct bank 38 Ground conductors can also be placed in conduits provided that they 39 intercept radiated fields 40

2) Establish a ground bus around the perimeter of the manhole with at least two 41 ties to the substation grid This ground bus provides a convenient means of 42 grounding individual cable shields if required 43




c) Parallel ground conductors for directly buried cables 1

1) Place one or more ground conductors in proximity of each cable run if cable 2 paths are diverse 3

d) Protection for unshielded cables 4

1) Ground conductors provide protection to both shielded and unshielded cables 5 However unshielded cables receive more benefit from the parallel ground 6 conductors To be most effective the ground conductors should be as close 7 to the cables as possible 8

2) In an unshielded cable grounding of unused conductors at both ends provides 9 the most effective protection (ldquoTransient pickup in 500 kV control circuitsrdquo 10 [B161]) Provisions should be made for replacement with shield conductors 11 should the unused conductors later be used for active circuits A parallel ground 12 conductor should accompany the cable if a spare conductor is grounded at both 13 ends 14

G3 Protection measuresmdashspecial circuits 15

This clause provides shielding and grounding guidelines for special circuits such as circuits to 16 CVTs CTs capacitor banks and coupling capacitor line tuning equipment The clause also 17 provides shielding guidelines for high-voltage power cables coaxial and triaxial cables and 18 the cables carrying low magnitude signals 19

G31 Instrument transformers (CVTs and CTs) 20

Equipment such as CVTs can couple high common-mode voltages to low-voltage secondary 21 cables originating from the base cabinet The source of transients in many of such cases is the 22 capacitive current interruption by an air break switch The surge impedances of the ground 23 leads connecting the CVT bases to local ground grid are primarily responsible for developing 24 these high transient voltages The transient voltages are coupled to the low-voltage circuit via 25 devicersquos stray capacitance 26

Measuring CTs are normally located in breaker bushings The bushing capacitances generate 27 the voltage transients on breaker casings in the same manner as the CVT devices These 28 transients then can be coupled to CT secondary circuits or any low-voltage circuit or 29 equipment residing in the breaker cabinet 30

The coupled voltages are typically reduced by lowering surge impedances of the ground leads 31 and the surrounding ground grid This can be accomplished by mounting the CVT or breaker 32 cabinets as close to the ground as permitted by clearance standards and by providing multiple 33 low-resistance conductors between the cabinets (for three standalone cabinets) and between 34 the cabinets and the station ground grid The secondary circuits exiting the cabinets should run 35 in the vicinity of the ground leads Additionally the secondary cables should be laid out 36 radially and as close to the ground grid conductors as possible If ground grid conductors in the 37 proximity are not available dedicated ground conductors should be installed Using shielded 38 cables for secondary circuits can provide additional immunity In such a case the shield 39 should be grounded at both ends Instrument transformer secondaries should be connected to 40 ground at only one point (see IEEE Std C57133 [B113]) Making the ground connection at 41 the relay or control building has the following advantages 42

a) Voltage rise is minimized near the relay equipment 43




b) The shock hazard to personnel in the building may be reduced 1

c) All grounds are at one location facilitating checking 2

CT secondary leads in a primary voltage area exceeding 600 V should be protected as required 3 by Rule 150 of the NESC (Accredited Standards Committee C2) 4

G32 Shunt capacitor banks 5

In the case of a grounded shunt capacitor installation operated at 115 kV and higher voltage 6 the EMI can be controlled by the use of shielded cables and grounding the shields at both 7 ends However in the case of multiple banks requiring back-to-back switching special 8 protection measures may be necessary (ldquoShunt capacitor switching EMI voltages their 9 reduction in Bonneville Power Administration substationsrdquo [B37]) A pre-insertion resistor or 10 current limiting reactor inserted between the banks can substantially reduce the switching 11 transient in back-to-back switching Closing the circuit switcher at a ldquozero voltagerdquo point on 12 the voltage wave can also reduce the transient significantly Special shielding and grounding 13 practices as listed below may however be required in absence of such mitigation methods 14

a) Route instrumentation and control circuits directly under the supply buses and close 15 to ldquopeninsulardquo ground grid conductors until they are a minimum of 6 m (20 ft) within 16 the influence of the main substation ground grid 17

b) Ground the end of the cable shield in the capacitor yard to a ldquopeninsulardquo grounding 18 system 19

c) Ground the cable shield to the ground grid at the nearest manhole hand hole trench 20 or tunnel adjacent to the capacitors 21

d) Ground the shield at the entrance to the control or relay house 22

e) If the shield is extended beyond the entrance into the control or relay house ground 23 the shield at the switchboard or other cable termination 24

f) Capacitor yard lighting and receptacle circuits should also be shielded if the light 25 posts are grounded to ldquopeninsulardquo grounding If the light posts are not grounded to 26 ldquopeninsulardquo grounding they should be located a minimum of 2 m (6 ft) away from 27 any structure that is grounded to the ldquopeninsulardquo grounding This will reduce the 28 probability of personnel simultaneously contacting both structures and being in series 29 with the potential difference between the peninsula and the rest of the grid during 30 capacitor switching or during a fault 31

g) In the manhole adjacent to the capacitor yard where capacitor cable shields are 32 grounded ground all other cable shields even if they are not related to the capacitors 33 Also ground all cable shields grounded in this manhole at their remote ends During 34 capacitor switching and faults the potential of the peninsula ground grid and the area 35 around the first manhole may be quite high A high voltage could exist between 36 cables if some shields are not grounded and between the ends of the shields if both 37 ends are not grounded 38

h) High-voltage shunt capacitor banks of a given voltage should have the neutrals from 39 individual banks connected together and then connected to the station ground grid at 40




only one point To facilitate single point grounding all capacitor banks of a given 1 voltage should be at one location 2

G33 Gas insulated substations (GIS) 3

Operation of high-voltage (725 kV and above) GIS breakers and disconnect switches generate 4 transients with much faster rise time than air insulated equipment resulting in higher 5 frequency transients (frequency bandwidth roughly one order of magnitude greater) that can 6 increase the coupling of interference into control wiring Transients can also be generated 7 within substation grounds GIS manufacturers will typically supply shielded cable for control 8 and power circuits between equipment and the local control panel on the skid Shielded cable 9 is also recommended for (customer) circuits terminating at the GIS equipment or in the near 10 vicinity of GIS equipment Shields should be grounded at both ends and the grounding pigtails 11 are to be as short as possible grounded immediately inside the control cabinet The grounds 12 prevent bringing the transients into the control cabinet where they could couple with other 13 conductors For more information refer to IEEE Standard C371221 [B110] 14

G34 High susceptibility circuits 15

This subclause provides guidance for shielding and grounding of control and instrumentation 16 circuits with high susceptibility to steady-state noise High susceptibility circuits are those 17 carrying low level voltage and current signals A thermocouple circuit carrying analog signals 18 in millivolt range is one good example of this type of circuit 19

The protection measures described in this section may not be necessary if interference due to 20 steady-state noise is not a concern even for high susceptibility circuits Users should follow the 21 general shielding and grounding practices described in G2 in such cases 22

For further details on shielding and grounding of high susceptibility circuits see IEEE Std 23 1050 [B95] For information on application of instrumentation and control cables for SCADA 24 see IEEE Std C371 [B106] 25

G341 Use of twisted pair cable 26

The use of twisted pair cables is an effective method for reducing steady-state differential 27 mode noise on high susceptibility cables Using cables with twisted pair conductors and 28 individually insulated shields over each pair is also effective in minimizing crosstalk in 29 communication circuits 30

G342 Grounding of signal circuit 31

The signal circuit may originate at a source such as a transducer and terminate at a receiver 32 (load) such as a recorder or a SCADA RTU either directly or through an amplifier 33

If the receiver is receiving the signal from a grounded voltage source a thermocouple for 34 example the receiver input should be capable of high common-mode rejection This can be 35 accomplished by either isolating the receiver from the ground or installing a differential 36 amplifier with isolated guard at the receiver input terminals Isolating the circuits from ground 37 effectively opens the ground common-mode voltage path in the signal circuit If a single-ended 38 amplifier already exists at the input terminal of the receiver the low side of the signal circuit is 39




not broken and should be considered grounded at the terminal In this case the same isolation 1 procedure as indicated above should be followed 2

When an ungrounded transducer is used the receiver may not need isolation In such a case a 3 single-ended amplifier can be installed at the input terminal if required 4

G343 Shield grounding 5

In the case of a high susceptibility circuit the shield may be connected to ground at only one 6 point preferably where the signal equipment is grounded If the shield is grounded at some 7 point other than where the signal equipment is grounded charging currents may flow in the 8 shield because of the difference in voltages between signal and shield ground locations 9 Similarly if the shield is grounded at more than one point voltage gradients along the ground 10 conductors may drive current through the shield In either case the common mode noise 11 current in the shield can induce differential mode noise in the signal leads Depending on the 12 unbalance in the signal circuit noise voltages of sufficient magnitudes may be developed to 13 reduce the accuracy of the signal sensing equipment 14

In a system with a grounded transducer at one end and an isolated differential amplifier at the 15 receiving end connecting the cable shield to the amplifier guard shield may reduce the 16 amplifierrsquos common-mode rejection capability A preferred practice in such a case is to 17 isolate the cable shield from the amplifier guard shield and to ground the shield only at the 18 transducer end This shield grounding practice minimizes the shield-induced common-mode 19 current while permitting the amplifier to operate at maximum common- mode rejection 20 capability 21

To provide immunity from transient overvoltages the nongrounded end of the shield may be 22 grounded through a suitable capacitor or a surge suppressor varistor 23

G35 Shielding terminations at the equipment 24

The following guidelines may be followed for the circuits entering equipment located in the 25 control building or yard 26

a) If cable shields are grounded at the entrance of the control building they should be 27 extended beyond the building entrance and grounded at their final terminations in the 28 cabinet 29

b) To minimize the size of the loop formed between the cable and the shield carry the 30 shield with the cable as far towards the equipment as practical before grounding 31

G36 Cables and shielding for power-line carrier (PLC) equipment 32

The circuits for PLC equipment typically consist of three specific types of cables These types 33 are as follows insulated single conductor coaxial cable and triaxial cable For additional 34 guidance on PLC and circuits refer to IEEE Std 643 [B87]) 35




G361 Insulated single conductor 1

An insulated single conductor is used to connect a coupling capacitor to line-tuning equipment 2 or outdoor transmitting and receiving equipment It can also be used as the interconnecting 3 lead for short bypasses 4

Bare conductors and coaxial cables should be avoided for these applications since either one 5 can introduce excessive leakage currents or excessive stray capacitance 6

Since a single conductor is at a high impedance point when connected between a coupling 7 capacitor and a line tuner stray capacitance-to-ground and leakage currents can affect the 8 coupling circuit performance The stray capacitance can cause a reduction in bandwidth and 9 the leakage currents can cause a loss in carrier power 10

To reduce stray capacitance and leakage currents either of the following methods may be 11 used 12

a) An insulated single conductor should be run as directly as possible between its 13 required terminations It should be mounted on insulators and fed through bushings at 14 each end The conductor insulation should be unbroken between its ends to maintain 15 low leakage 16

b) An insulated single conductor can be installed in a nonmagnetic flexible metal 17 conduit which is sheathed in a vinyl jacket The insulated single conductor should be 18 isolated from the flexible metal conduit with nonconductive washers spaced about 19 150 mm (6 in) apart If the conductor has a significant portion of its length outside the 20 flexible metal conduit it should be mounted on insulators and fed through bushings at 21 its ends as in item a) 22

A typical insulated carrier lead 12 mm (048 in) in diameter consists of a single 8 AWG 19-23 strand conductor having rubber insulation and a neoprene outer jacket 24

G362 Coaxial cables 25

This type of cable is sometimes used for a low-impedance interconnection between a line tuner 26 and a transmitterreceiver or between line tuners in a long bypass It is sometimes used 27 between an impedance- matching transformer in a coupling capacitor base and a 28 transmitterreceiver 29

In these applications the copper braid (shield) that forms the outer conductor of the cable 30 should be grounded at the transmitterreceiver end only (or at only one end of a bypass) If 31 both shield ends are grounded large surge currents can flow under certain conditions causing 32 saturation of the impedance- matching transformer and resulting in an inoperative carrier 33 channel 34

G363 Triaxial cables (or shielded coaxial cable) 35

On transmission lines operating at voltages greater than 230 kV triaxial cable may be used 36 instead of coaxial cable This cable provides an additional heavy shield which does not carry 37 signal currents The outer shield is capable of carrying large induced surge currents under fault 38 conditions and is grounded at both ends This arrangement provides an effective shielding 39 against both magnetic and electrostatic induction 40




Annex H 1

(normative) 2

Electrical segregation 3

Physical separation between a transient source and control cables is an effective means of 4 transient control Because mutual capacitance and mutual inductance are greatly influenced by 5 circuit spacing small increases in distance may produce substantial decreases in interaction 6 between circuits 7

Table H1 provides the allowable mixing requirements for segregation of various types of 8 circuits in raceways Table H1 is not intended to cover typical lsquobuildingrsquo wiring such as for 9 lighting heatingair conditioning receptacles etc This type wiring generally should follow 10 national or local electrical codes 11

Table H1mdash Circuit mixingsegregation in raceways 12

Raceway system Circuit types typically installed together

Individual ducts conduits Control and instrumentation and power only if le 120 V (ac) Single conductor smaller than 6 AWG should be segregated from multiconductor cable except in runs le 6 m (20 ft) Communication circuits should be in a dedicated duct whenever possible or sub-duct if in a shared duct

Duct banks All types segregated as necessary into individual ducts

Trench All types Barrier recommended for power circuits greater than 240 V (ac) Communication circuits should be installed in a sub-duct

Tray or wireways Control and instrumentation communication power only if le 120 V (ac) Communication circuits may be installed in a sub-duct or separate tray system

Connecting raceways le 18 m (6 ft) (eg between junction box and equipment cabinet)

Control and instrumentation communication power only if le 120 V (ac) Communication circuits may be installed in a sub-duct

aControl and instrumentation circuits include dc circuits ac control circuits potential transformer circuits current transformer circuits and 13

instrumentation (milli-amp or low voltage) circuits For the purposes of raceway assignment dc power circuits to equipment such as to motor 14 operated air switches circuit breaker charging mechanisms etc or for dc lighting are considered the same as control circuits 15 bPrimary dc circuits including charger to battery battery to distribution panel and panel to panel primary connections are to be in dedicated 16

raceways 17 cThe station service feeder from the station service transformer to the primary distribution panel may be in a dedicated raceway 18




Annex I 1

(normative) 2

Separation of redundant cables 3

This annex provides guidance for the separation of redundant cable systems 4

The requirements for redundancy can vary substantially based on application variables This 5 annex applies to the redundancy of cables and raceways only The redundancy of the other 6 components should be considered when designing the redundancy of the cable systems 7

I1 Redundant cable systems 8

Redundant cable systems are two or more systems serving the same objective They may be 9 systems where personnel safety is involved such as fire pumps or systems provided with 10 redundancy because of the severity of economic consequences of equipment damage or system 11 reliability Primary and backup relay control cables and normal and backup station service 12 supplies are practical examples of redundant cable systems 13

Communication cables may be used in communication systems that provide redundancy on a 14 variety of levels Care should be undertaken to understand how the communication cables 15 impact redundant functionality For example communication redundancy may involve 16 redundant communications ports on each device where two cables may be providing 17 communication access to one device In this case it may or may not be desirable to have these 18 two cables follow the same path One other common example is when primary and secondary 19 IEDs both have a single communication cable but both IEDs may not be used in a redundant 20 fashion for all functionality In the case where both devices support the same functions in a 21 redundant manner the discussion below may be applied 22

Communication cables may also be impacted by diversity or redundancy requirements Some 23 applications may require communications cables for primary and secondarybackup functions 24 to take different paths within the substation to reduce the likelihood that the same failure mode 25 will simultaneously affect both cables Consult specific application requirements for the level 26 of diversity required 27

I2 Design considerations 28

Redundant cable systems should be physically and electrically separated to reduce the chance 29 that a single event whether physical in nature or electrical in nature could prevent a required 30 specific substation operation The degree and type of separation required varies with the 31 importance of the cable systems the equipment they serve and potential hazards in particular 32 areas of the substation System owners or regulatory agencies may have requirements that 33 mandate certain redundancy and separation practices 34




I3 Separation 1

Physical and electrical separation of redundant cable systems increases the reliability of the 2 cable systems and the equipment they serve Possible methods to provide physical and 3 electrical separation include 4

mdash Installation of redundant systems in separate raceways trays trenches or conduits 5 with diverse physical routing 6

mdash Fire barrier between systems that are contained within the same raceway 7

mdash Avoidance of stacked cable trays or raceways that contain redundant systems 8

mdash Use of independent electrical power sources (DC battery AC station service source) 9 and distribution panels for power cables in separate cable systems 10

mdash Physical separation of power or signal sources (instrument transformers 11 monitoringindication devices DC battery AC station service source or power 12 distribution panels) for control and instrumentation cables 13

mdash Physical separation of connected devices (protective relays and relaying panels 14 RTUrsquos HMIrsquos DFRrsquos phone system fiber splicepatch panels) for control 15 instrumentation communication and fiber cables 16




Annex J 1

(normative) 2

Cable pulling tension calculations 3

Ethernet cables have cable pulling limits and minimum bend radius defined in TIA-568-C0 4 [B10] For other types of copper communication cables the manufacturerrsquos pulling tension 5 and bend radius guidelines should be followed 6

J1 Cable pulling design limits and calculations 7

The following design limits and formulas provided in this clause should be utilized when 8 determining the maximum safe cable pulling lengths and tensions Raceway fill maximum 9 sidewall pressure jam ratio and minimum bending radius are design limits which should be 10 examined in designing a proper cable pull 11

These design limits are prerequisites needed in designing a cable raceway system Once these 12 limits are determined for a particular cable the raceway system can then be designed If the 13 system has already been designed modifications may be required in order to pull the cable 14 without damage 15

Conduit and duct system design should consider the maximum pulling lengths of cable to be 16 installed The maximum pulling length of a cable or cables is determined by the maximum 17 allowable pulling tension and sidewall pressure The pulling length will be limited by one of 18 these factors 19

Pull points or manholes should be installed wherever calculations show that expected pulling 20 tensions exceed either maximum allowable pulling tension or sidewall pressure Also an 21 industry ldquorule of thumbrdquo is no more than 360deg of total bends along the cable pull though 22 actual calculations will override this ldquorule of thumbrdquo 23

A sample calculation for determining cable pulling tensions is shown in J4 and O6 24

J2 Design limits 25

J21 Maximum allowable pulling tension 26

The maximum allowable pulling tension is the minimum value of Tmax from the applicable 27 following guidelines unless otherwise indicated by the cable manufacturer 28

The maximum tension on an individual conductor should not exceed 29

AKTcond (J1) 30

where 31




Tcond is the maximum allowable pulling tension on individual conductor in newtons 1 (pounds) 2

A is the cross-sectional area of each conductor in square millimeters (mm2) (kcmil) 3 K equals 70 Nmm2 (8 lbkcmil) for annealed copper and hard aluminum 4 K equals 525 Nmm2 (6 lbkcmil) for 34 hard aluminum 5 6

When pulling together two or three conductors of equal size the pulling tension should not 7 exceed twice the maximum tension of an individual conductor ie 8

condTT 2max (J2) 9

When pulling more than three conductors of equal size together the pulling tension 10 should not exceed 60 of the maximum tension of an individual conductor times the 11 number of conductors (ldquoNrdquo) ie 12

condTNT 60max (J3) 13

When pulling using a pulling eye the maximum tension for a single-conductor cable 14 should not exceed 222 kN (5000 lb) and the maximum tension for two or more 15 conductors should not exceed 267 kN (6000 lb) The cable manufacturer should be 16 consulted when tensions exceeding these limits are expected 17

When pulling by basket grip over a nonleaded jacketed cable the pulling tension 18 should not exceed 445 kN (1000 lb) 19

When using a basket-weave type pulling grip applied over a lead-sheathed cable the 20 force should not exceed 667 kN (1500 lb) as determined by the following formula 21

)(max tDKT m (J4) 22

where 23

t is the lead sheath thickness in millimeters (inches) 24 D is the OD of lead sheath in millimeters (inches) 25 Km is the maximum allowable pulling stress in MPa (1034 MPa to 138 MPa 26

[1500 to 200 psi] depending on the lead alloy) 27 28

NOTEmdashFor lead-sheathed cables with neoprene jackets Tmax = 445 kN (1000 lb) 29

Pulling instructions for coaxial triaxial and other special cables should follow the 30 manufacturerrsquos recommendations 31

J22 Maximum allowable sidewall pressure 32

Sidewall pressure P is defined as the tension out of a bend expressed in newtons (pounds) 33 divided by the radius of the bend expressed in millimeters (feet) The sidewall pressure on a 34 cable can be calculated by the following equations 35




Single cable in conduit 1

r

TP 0 (J5) 2

Three cables in cradle configuration where the center cable presses hardest against the conduit 3

r

TcP

3

)23( 0 (J6) 4

Three cables in triangular configuration where the pressure is divided between the two bottom 5 cables 6

r

TP

20 (J7) 7

Four cables in diamond configuration where the bottom cable is subjected to the greatest 8 crushing force 9

r

TcP

3

)23( 0 (J8) 10

where 11

P is the sidewall pressure in newtonsmillimeter (poundsfoot) of radius 12 To is the tension out of the bend in newtons (pounds) 13 c is the weight correction factor (refer to J31) 14 r is the inside radius of bend in millimeters (feet) 15

16

Equation (J6) Equation (J7) and Equation (J8) calculate the sidewall pressure for the cable 17 with the highest sidewall pressure 18

The maximum allowable sidewall pressure is 7300 Nm (500 lbft) of radius for 19 multiconductor power cables and single-conductor power cables 6 AWG and larger subject to 20 verification by the cable manufacturer The recommended maximum allowable sidewall 21 pressure for control cables and single- conductor power cable 8 AWG and smaller is 4380 Nm 22 (300 lbft) of radius subject to verification by the cable manufacturer For instrumentation 23 cable the cable manufacturerrsquos recommendations should be obtained 24

J23 Jam ratio 25

Jamming is the wedging of cables in a conduit when three cables lie side by side in the same 26 plane Jam ratio is defined for three cables of equal diameter as the ratio of the conduit inside 27 diameter (D) to the cable outside diameter (d) The jam ratio is a concern because jamming in 28 the conduit could cause damage to one or more of the cables The possibility of jamming is 29




greater when the cables change direction Therefore the inside diameter of the conduit at the 1 bend is used in determining the jam ratio 2

Jamming cannot occur when 3

03d

D 4

Jamming is not likely when 5

82d

D 6

Jamming is probable when 7

0382 d

D 8

A 40 conduit fill gives a jam ratio of 274 which is in the region where jamming is not 9 likely The inside diameter of a field-bent conduit is usually increased by 5 to account for the 10 oval cross-section that occurs Adding 5 for a field bent conduit yields a jam ratio of 287 11 which is in the region where jamming is probable 12

J24 Minimum bending radius 13

The minimum bending radius is the minimum radius to which a cable can be bent while under 14 a pulling tension providing the maximum sidewall pressure is not exceeded The values given 15 are usually stated as a multiple of cable diameter and are a function of the cable diameter and 16 whether the cable is nonshielded shielded armored or single or multiple conductor Guidance 17 for minimum bending radii can be obtained from the NEC [B144] or the cable manufacturer 18

J3 Cable-pulling calculations 19

The equations used to calculate the expected cable-pulling tension are based on the number of 20 cables to be pulled the type of raceway the cable configuration in the raceway and the 21 raceway layout 22

J31 Straight sections of conduit or duct 23

For a straight section of conduit or duct the pulling tension is equal to the length of the 24 straight run multiplied by the weight per unit length of cable the coefficient of friction and the 25 weight correction factor 26

In SI units 27

T = Lmgfc (J9) 28

where 29




T is the pulling tension in a straight duct in newtons 1 L is the length of the straight duct in meters 2 m is the mass of the cable per unit length in kilogramsmeter 3 g is the acceleration of gravity in 981 ms2 4 f is the coefficient of friction 5 c is the weight correction factor 6 7

In English units 8

T = Lwfc (J10) 9

where 10

T is the total pulling tension of straight run in pounds 11 L is the length of the straight run in feet 12 w is the weight of the cable(s) in poundsfoot 13 14

The coefficient of friction is usually assumed to be as given in Table J 1 15

Table J1mdash Coefficient of friction f 16

Dry cable or ducts 05 Well-lubricated cable and ducts 015 to 035

17

The weight correction factor takes into account the added frictional forces that exist between 18 triangular or cradle arranged cables resulting in a greater pulling tension than when pulling a 19 single cable The weight correction factor can be calculated by the following equations 20

Three single cables in cradled configuration 21

2

3

41

dD

dc (J11) 22

Three single cables in triangular configuration 23

2

1

1

dD

dc (J12) 24

Four single cables in diamond configuration 25

2

21

dD

dc (J13) 26




where 1

D is the conduit inside diameter 2 d is the single conductor cable outside diameter 3 4

The weight correction factor for three single-conductor cables can be determined from Figure 5 J1 6

7 Figure J1mdash Weight correction factor (c) 8

J32 Inclined sections of raceway 9

The expected pulling tension of a cable in an inclined section of duct may be calculated from 10 the following Equation (J13) and Equation (J14) 11

)sincos( cfwLTup (J14) 12




)sincos( cfwLTdown (J15) 1

where 2

α is the angle of the incline from horizontal 3

J33 Horizontal and vertical bends 4

The tension out of a horizontal or vertical conduit bend is normally calculated from the 5 following approximate equation 6

cfinout eTT (J16) 7

where 8

Tout is the tension out of bend in kilonewtons (pounds) 9 Tin is the tension into the bend in kilonewtons (pounds) 10 θ is the angle of the change in direction produced by bend in radians 11 12

This is a simplified equation which ignores the weight of the cable It is very accurate where 13 the incoming tension at a bend is equal to or greater than 10 times the product of cable weight 14 per meter (foot) times the bend radius (r) expressed in meters (feet) If the tension into a bend 15 is less than 10wr the exact equations can be found in ldquoPipe-line design for pipe-type feedersrdquo 16 [B111] Cases in which the exact equations may become necessary are where light tensions 17 enter large radii bends Usually Equation (J15) is precise enough for normal installations 18

J4 Sample calculation 19

This subclause is intended to illustrate the calculations required to determine cable pulling 20 tensions in a typical run from a manhole to a riser pole The typical duct run used for the 21 calculations is shown in Figure J2 22

A

B

C D E

F G

Riser Pole

Substation Manhole

A-B ndash 3 m (10 ft) Vertical RiserB-C ndash 12 m (4 ft) 90o Inside Radius Vertical CurveC-D ndash 152 m (500 ft)D-E ndash 38 m (125 ft) 45o Inside Radius Vertical CurveE-F ndash 30 m (100 ft)F-G ndash 38 m (125 ft) 45o Inside Radius Vertical CurveG-H ndash 60 m (200 ft)

H

23 Figure J2mdash Duct layout for example calculations 24

The cable to be used in this example installation is 3-1c 750 kcmil triplexed frac34 hard-drawn 25 aluminum cable with 13 concentric neutral The completed weight of this cable is 784 Nm 26




(5375 lbft 8 kgm) and the OD for each cable is 409 cm (161 in) Plastic conduit suitable 1 for direct burial (Type DB) is to be used for this example installation Assume that pulling eye 2 is used for cable pulling 3

J41 Conduit fill and jam ratio 4

In determining the size of conduit required consideration should be given to conduit fill and 5 jam ratio Using Equation (E1) of this guide the percent fill is given in Equation (J17) 6

100_

_

areaRaceway

areaCableFill (J17) 7

Using 10 cm (4 in) conduit with an internal diameter of 1023 cm (4026 in) 8

9847100

2

2310

2

0943

2

2

Fill 9

Since 4798 exceeds the maximum allowable fill of 40 the percent fill should be 10 calculated for the next larger size conduit 13 cm (5 in) with an internal diameter of 1282 cm 11 (5047 in) 12

530100

2

8212

2

0943

2

2

Fill 13

This is an acceptable fill 14

The jam ratio as discussed in J23 should be calculated next Assuming field bending of the 15 conduit 16

d

DRatioJam

051_ (J18) 17

where 18


293094

)8212(051_ RatioJam 22




Jamming cannot occur based on J23 of this guide Also where triplexed cable is used 1 jamming is not a problem since jamming is the wedging of cables in a conduit when three 2 cables lie side by side in the same plane 3


The maximum allowable pulling tension for this example cable is calculated by using Equation 5 (J1) and Equation (J2) 6

Tcond = K middot A 7

Tcond = (525)(381) = 20 kN (4500 lb) 8

Tmax = 2 middot Tcond = 2 times 20 = 40 kN (9000 lb) 9

However as indicated in J2 1 the maximum tension for two or more conductors should not 10 exceed 267 kN (6000 lb) when pulling using a pulling eye 11


The minimum bending radius in accordance with the cable manufacturerrsquos recommendation 13 for the example cable is 12 times the overall diameter of the cable The cabling factor for three 14 conductors triplexed is 2155 15

Minimum bending radius = (12)(2155)(409) = 1056 cm (416 in) 16

J44 Pulling tensions 17

The pulling tensions for the example are calculated using Equation (J9a) or Equation (J9b) 18 for straight runs and Equation (J15) for vertical or horizontal bends 19

Pulling from A towards H 20

Since pulling down the vertical section A-B and around the curve B-C would require a 21 negligible tension the calculations are started at C 22

The weight correction factor (c) for three single cables in a triangular configuration is 23 calculated using Equation (J11) 24

131

0948212

0941

12

c 25

Therefore assuming a dry cable or duct with a coefficient of friction of 05 26

TD = (152)(8)(981)(05)(113) = 673 kN (1518 lb) 27

TE = TDecfθ 28




where 1

θ is the angle of the change in direction produced by bend in radians 2 3

NOTEmdashConversion factor from degrees to radians is 001745 4

TE = 673 e(113)(05)(45)(001745) 5

TE = 673 e04437 6

TE = 105 kN (2366 lb) 7

TF = TE + (30)(8)(981)(05)(113) 8

TF = 105 + 133 9

TF = 118 kN (2670 lb) 10

TG = T Fecfθ 11

TG = 118e(113)(05)(45)(001745) 12

TG = 118 e04437 13

TG = 184 kN (4161 lb) 14

TH = TG + (60)(8)(981)(05)(113) 15

TH = 184 + 266 16

TH = 211 kN (4768 lb) 17

This is within the maximum allowable tension of 267 kN (6000 lb) However the maximum 18 sidewall pressure of 7300 Nm (500 lbft) should also be checked The maximum sidewall 19 pressure for this pull will occur at curve F-G and is calculated using Equation (J7) 20

)8103)(2(

)40018)(131(P 274 kN (188 lbft) 21

P=( 113 x 18400)(2 x 3800) =274 Nmm = 2740Nm = 274 kNm 22

This is acceptable 23

Pulling from H towards A 24

TG = Lmgfc 25

TG = (60)(8)(981)(05)(113) 26

TG = 266 kN (607 lb) 27

TF = TGecfθ 28




TF = 27e04437 1

TF = 42 kN (946 lb) 2

TE = TF + (30)(8)(981)(05)(113) 3

TE = 42 + 13 4

TE = 55 kN (1250 lb) 5

TD = 55ecfθ 6

TD = 55e(113)(05)(45)(001745) 7

TD = 55e04437 8

TD = 86 kN (1948 lb) 9

TC = TD + (152)(8)(981)(05)(113) 10

TC = 86 + 67 11

TC = 153 kN (3466 lb) 12

TB = 153ecfθ 13

TB = 153e(113)(05)(90)(001745) 14

TB = 153e08873 15

TB = 372 kN (8417 lb) 16

This tension exceeds the maximum allowable tension of 267 N (6000 lb) Therefore a cable 17 pull from H to A should not be permitted The cable should be pulled from A to H The let-off 18 reel should be at the riser pole and the cable should be pulled toward the manhole in order not 19 to exceed the maximum allowable pulling tension or sidewall pressure 20




Annex K 1

(normative) 2

Handling 3

This annex provides guidance for the construction methods materials and precautions in 4 handling and storing cable 5

Care should be used when using gel-filled communication cables The gel should only be 6 cleaned using manufacturer-recommended cleaning solutions Improper cleanup of the gel 7 may result in cable damage 8

K1 Storage 9

Reels should be stored upright on their flanges and handled in such a manner as to prevent 10 deterioration of or physical damage to the reel or to the cable During storage the ends of the 11 cables should be sealed against the entrance of moisture or contamination Reels should be 12 stored on solid ground to prevent the flanges from sinking into the earth Cables should be 13 stored in an environment that does not exceed the storage environmental specification 14 provided by the vendor 15

NOTEmdashWhen stored outside for long periods of time (longer than typical installation staging periods) the cable will 16 require protection from sunlight (UV radiation) It is preferable to store the cable inside if UV protection cannot be 17 provided 18

K2 Protection of cable 19

a) If the cable manufacturerrsquos recommended maximum pulling tension sidewall 20 pressure or the minimum bending or training radius is violated damage could occur 21 to the cable conductor insulation shield or jacket This could lead to premature 22 failure andor poor life-cycle operation 23

b) Special care should be exercised during welding soldering and splicing operations to 24 prevent damage to cables If necessary cables should be protected by fire-resistant 25 material 26

c) Cables should be sealed before pulling and resealed after pulling regardless of 27 location 28

d) If water has entered the cable a vacuum should be pulled on the cable or the cable 29 should be purged with nitrogen to extract the water and tested for dryness 30

e) Prior to and after the cable pull is complete the cable manufacturerrsquos 31 recommendations for minimum bending radii should be followed 32




Annex L 1

(normative) 2

Installation 3

This annex provides guidance for the construction methods materials and precautions in 4 installing cable systems Fiber optic cable is addressed separately in Clause 6 5

L1 Installation 6

a) The cable manufacturerrsquos recommended temperature limits should be followed when 7 pulling or handling cables during extreme low temperatures Handling or pulling 8 cables in extremely low temperatures can cause damage to the cable sheathing 9 jacketing or insulation To prevent damage of this nature store cables in a heated 10 building at least 24 hours prior to installation 11

b) Table L1 provides the cable manufacturerrsquos recommended low temperature limits for 12 handling and pulling cables with various types of jackets or insulations 13

c) Cable-pulling lubricants should be compatible with the cable outer surface and should 14 not set up or harden during cable installation The lubricant should not set up so as to 15 prevent the cable from being pulled out of the conduit at a later time Cable lubricants 16 should not support combustion 17

d) Pulling winches and other equipment should be of adequate capacity to provide a 18 steady continuous pull on the cable Use of truck bumpers is not recommended for 19 longer pulls due to risk of unsteady pull 20

e) Cable reels should be supported so that the cable may be unreeled and fed into the 21 raceway without subjecting the cable to a reverse bend as it is pulled from the reel 22

f) A tension measuring device should be used on runs when pulling-force calculations 23 indicate that allowable stresses may be approached 24

g) Pulling tension will be increased when the cable is pulled off the reel Turning the 25 reel and feeding slack cable to the duct entrance will reduce the pulling tension 26

h) A suitable feeder device should be used to protect and guide the cable from the cable 27 reel into the raceway The radius of the feeder device should not be less than the 28 minimum bending radius of the cable If a feeder device is not used the cable should 29 be hand-guided into the raceway 30

i) A swivel should be attached between the pulling eye and the pulling cable 31 Projections and sharp edges on pulling hardware should be taped or otherwise 32 covered to protect against snagging at conduit joints and to prevent damage to the 33 conduit 34

j) The direction of pulling has a large influence on the pulling tension in conduit runs 35 containing bends Whenever a choice is possible the cable should be pulled so that 36




the bend or bends are closest to the reel The worst condition possible is to pull out of 1 a bend at or near the end of the run 2

k) Pulling instructions for all cable should follow the cable manufacturerrsquos 3 recommendations 4

l) Cable should be pulled only into clean raceways An appropriately-sized mandrel 5 should be pulled through all underground ducts prior to cable pulling Any abrasions 6 or sharp edges that might damage the cable should be removed 7

m) After cable installation has started trays and trenches should be cleaned periodically 8 as necessary to prevent the accumulation of debris 9

n) Sufficient cable slack should be left in each manhole and temporarily supported so 10 that the cable can be trained to its final location on racks hangers or trays along the 11 sides of the manhole Cable joints should not be placed directly on racks or hangers 12 (IEEE Std 404 [B75]) 13

o) The use of single- or multi-roller cable sheaves of the proper radius should be used 14 when installing cable around sharp corners or obstructions Minimum bending radius 15 should never be less than that recommended by the manufacturer 16

p) Cables should be installed in raceway systems that have adequately sized bends 17 boxes and fittings so that the cable manufacturerrsquos minimum allowable bending radii 18 and sidewall pressures for cable installations are not violated Guidance for the 19 number of bends between pull points and guidance on conduit fill can be found in the 20 NEC [B144] 21

q) Cables should be identified by a permanent marker at each end in accordance with the 22 design documents 23

r) Careful consideration should be given not only to design engineering and material 24 cost but also to the installed cost for the initial as well as the ultimate installation 25 Maintenance and replacement costs also should be considered It is desirable that the 26 system be designed so that additions and changes can be made with ease economy 27 and minimum outages 28

s) The ends of all cables should be properly sealed during and after installation to 29 prevent moisture collection as ambient temperature and humidity change 30

Table L1mdash Low temperature limits for cable handling and pullinga 31

Cable insulation or jacket material Low temperature limits

Degrees Celsius

Degrees Fahrenheit

EPR low temperature PVC mdash40 mdash40 CPE mdash35 mdash31 PVC mdash10 +14 CSPE mdash20 mdash4 Neoprene (PCP) mdash20 mdash4 XLPE mdash40 mdash40

Paper-insulated lead-sheathed mdash12 +10




aIf a cable has an insulation and jacket with different materials the higher 1 temperature limit should be used 2

L2 Supporting cables in vertical runs 3

Recommendations for supporting special cables such as armored shielded and coaxial should 4 be obtained from the cable manufacturer 5

The weight of a vertical cable should not be supported by the terminals to which it is 6 connected To prevent damage by deformation due to excessive bearing pressure or cable 7 tension vertically run cables should be supported by holding devices in the tray in the ends of 8 the conduit or in boxes inserted at intervals in the conduit system 9

Cables with copper conductors regardless of their voltage class installed in vertical runs 10 should be supported in accordance with Table L2 11

Table L2mdash Cable vertical support distances 12

Maximum distances between cable supports

Conductor sizes Maximum distance

AWG or kcmil ft m

14 to 10 100 30 20 to 40 80 24 250 to 350 60 18 Over 350 to 500 50 15 Over 500 to 750 40 12

Over 750 35 10

L3 Securing cables in vertical runs 13

Cables installed in vertical cable tray should be secured to the cable tray at least every 15 m (5 14 ft) 15

L4 Training cables 16

Cables installed in trays should be neatly trained to facilitate identification and removal and to 17 maximize tray fill 18

L5 Cable conductor terminations 19

a) Cable conductors should extend from terminal to terminal without splicing Wire 20 connections to the terminal blocks relays instruments control device etc should be 21 lugged Wire loops around terminals are not acceptable for stranded conductors 22

b) Terminal lugs should be installed without removing conductor strands 23

c) At all terminals suitable designations should be installed on each wire 24




d) All connections should be made so that undue bending or distortion should not occur 1 when any wire is removed from a stud or terminal 2

e) Wiring provided for connection of equipment which will be mounted by others 3 should be of ample length and terminated in a coil or pigtail 4

f) Before applying the wiring all edges corners and abrading surfaces which may 5 come in contact with the wires should be provided with an insulating cushion to 6 prevent damage to the wire insulation All holes through which wires pass should 7 have their edges insulated 8

g) Solderless indent type terminal lugs either seamless or having a brazed seam with 9 one hole closed-end tongue are recommended Indent should be adequate for 10 connection The pad of the terminal should have adequate surface to make contact 11 with terminal block or devices 12

h) If bare terminal lugs are used insulating sleeves may be used to cover the lug barrel 13 and any exposed part of the conductor 14

i) All terminals should be accessible for tightening with a straight socket wrench or 15 screwdriver 16

j) Connections to main control buses should be made with solderless connectors 17

k) The terminal lug manufacturerrsquos recommended crimping tool should be used and 18 tested periodically to verify minimum conductor pull-out strength 19

l) Where large size conductors are connected to a terminal block adequate clearance for 20 insulation should be provided between conductors and between conductor and 21 ground Terminal lugs for large size conductors should be compression type 22

m) The use of mechanical lugs on large conductors (such as main lugs in panelboards) 23 requires proper strip length of insulation and torquing to recommended values 24




Annex M 1

(normative) 2

Acceptance testing 3

This annex provides guidance for the testing of cables after installation and prior to their 4 connection to equipment and includes cable terminations connectors and splices 5

M1 Purpose 6

The purpose of these tests is to verify that cable insulation damage did not occur during 7 storage and installation and that the cable was properly spliced and terminated It should be 8 noted however that these tests may not detect damage that may eventually lead to cable 9 failure in service eg damage to the cable jacket or insulation shield on medium-voltage 10 cable or to low-voltage cable insulation 11

M2 Tests 12

A simple continuity test can be performed to identify any broken conductors Low-voltage 13 power cables may be insulation-resistance tested prior to connecting cables to equipment 14 These cables may be tested as part of the system checkout 15


Safety precautions should be observed during all phases of testing Cable ends should be 19 properly cleaned of all conducting material Cable test results environmental conditions and 20 data should be recorded and filed for maintenance reference The following ldquomeggerrdquo test may 21 be performed on each control and power circuit as applicable for multiconductor or shielded 22 cables in conjunction with the cable manufacturerrsquos recommendations It should be noted that 23 in dry conditions the integrity of single-conductor cables may be difficult to validate with this 24 test This is true even in metallic conduits unless the damaged area happens to be in contact 25 with the conduit 26

The test voltage should be a minimum of 500 V (dc) The minimum acceptable insulation 27 resistance is R in MΩ = (rated voltage in kilovolts + 1) times 3048length in meters (1000length 28 in feet) 29

a) See Table M1 for 600 V cable the resistance values 30

Table M1mdash Resistance values for 600 V cable 31

Length m (ft)

R MΩ

305 (100) 16 610 (200) 8




Length m (ft)

R MΩ

914 (300) 53 122 (400) 4 152 (500) 32 183 (600) 27 213 (700) 23 244 (800) 2 274 (900) 18

305 (1000) 16

1

b) Testing of control cable and prefabricated cable assemblies in a similar manner is 2 suggested The cable manufacturerrsquos recommendations should always be considered 3

Power line carrier coaxial or triaxial shield to ground insulation should be tested to verify 4 insulation quality using a 500 Vdc megohm meter Failure of shield to ground insulation 5 during a system ground fault may prevent proper carrier operation For further guidance on 6 power line carrier coaxial or triaxial cable testing refer to IEEE Std 643 [B87] 7




Annex N 1

(normative) 2

Recommended maintenance and inspection 3

In regard to communication cables failure of the cable will result in communications trouble 4 Depending on the failure mode that communication loss can be exceedingly temporary and 5 cyclical to permanent There are many other communications problems that can cause 6 communication failure Any communication failure does not indicate a cable failure but when 7 a cable fails that failure is likely to cause a communication failure In this regard monitoring 8 communication status can be thought of potentially monitoring the cable health 9

With respect to maintenance and inspection of communication cables the following clauses 10 can be adapted to apply to communication cables 11

N1 General 12

In regard to maintenance and inspection practices manufacturerrsquos recommendations should be 13 followed if they exist unless operating experience dictates otherwise The following 14 information should be viewed as general guidelines only and should be modified to suit the 15 situation 16

Furthermore it is understood that not all sections of the cable runs can be inspected due to the 17 routing of the circuit through ducts or conduits or because it is direct buried or installed in a 18 heavily utilized cable tray Therefore decisions based on inspections of accessible areas may 19 have some associated risk since the ldquobadrdquo section of the cable may not be visible or easily 20 accessible It may be assumed that if one section is in poor shape then the inaccessible 21 sections could be in worse shape Testing coupled with inspections is the best way to reduce 22 this risk 23

N2 Inspections 24

Normally inspections are done only when system investigations indicate the problem may lie 25 in the cable connection or when a condition assessment is required for potential sale of the 26 facility cable aging or as part of a reliability-centered-maintenance program 27

Visual inspection consists of looking for cracks splits or cuts in the cable jackets (or outer 28 covering) or possible signs of wear due to cable movement during thermal cycling or some 29 other item rubbing against the cable These breaches in the cablersquos protective jacket or 30 insulation may allow moisture to infiltrate which can lead to corrosion of the shielding or 31 cable sheath or an electrical fault Bulges and indentations can indicate moisture ingress or 32 insulating material movement which can also lead to corrosion or insulation failure 33

The cable termination connection should be tested for tightness by lightly tugging on them 34 while any bolted connections should be checked for proper tightness Infra-red technology can 35 also be used for larger power cables to check for overheating which can indicate loose 36 connections if clearances cannot be obtained 37




N3 Testing methods for metallic cables 1

a) Continuity A ldquoring-throughrdquo test using a simple door bell and battery circuit (or a 2 cable tracing device) can be used to confirm the cable is connected to the correct 3 location The cable circuit needs to be taken out of service during this testing though 4 This test method can also be used to check the continuity of any cable sheath shield 5 or grounding connection 6

b) Insulation A ldquoleakage testrdquo uses a device to apply a voltage equivalent to at least 7 50 of the cablersquos voltage rating to the cablersquos conductor and a ground point to test 8 the cablersquos insulation The voltage is applied for one minute The cable circuit needs 9 to be taken out of service and disconnected during this testing yet any sheath or 10 shield should remain in place and grounded Insulation in good condition should have 11 minimum leakage current and the voltage should not vary more than 10 (of the 12 selected test voltage) The leakage current should be steady or decreased from the 13 initial reading Unstabilized or increasing current levels over time indicate 14 deterioration 15

For all 600 V rated cables a minimum of 500 V (dc) is recommended so that 16 problems are more likely to be properly detected Since the magnitude of leakage 17 current is highly dependent upon a variety of factors (temperature humidity 18 condition of insulating material length of cable under test) these conditions should 19 be recorded to assess deterioration over time 20

c) Shield Any protective cable shield can also be tested using this same method but the 21 voltage applied should only be 50 of its nominal rating and it should be applied to 22 cablersquos sheath or shield which has been disconnected and isolated from ground 23

An ldquoinsulation testrdquo again using a device to apply a voltage between the cablersquos 24 conductor and its sheath or shield at equivalent to 50 of the cables voltage rating 25 can be used to test the cablersquos insulation The duration of this test should be one 26 minute The cablersquos sheath or shield and the conductor should be disconnected and 27 isolated from ground Again insulation in good condition should have minimum 28 leakage current and the voltage should not vary more than 10 29

For cables without sheaths or shielding it should be noted that there is no difference between 30 results of the ldquoleakage testrdquo or ldquoinsulation testrdquo 31

N4 Maintenance 32

The cycle of a regular maintenance program for cable and wires will depend on the age of the 33 cables the operating and environment conditions type of cable and outage availability It is 34 recommended that a visual inspection be done on at least an annual basis and that testing be 35 done when a problem is suspected 36

Cables installed in extreme conditions such as wet or high-temperature locations may need to 37 be inspected and tested on a more frequent basis depending on their age 38

For cables with potheads or shrink-type terminations which are installed in high-39 contamination areas it is recommended that they be cleaned on a regular basis dictated by 40 operating experience to help reduce or avoid the risk of electrical flashover to ground Cable 41 terminations should be cleaned using the manufacturerrsquos recommendations with the cable 42




circuit out of service and isolated Cleaning with high-pressure water is possible in some 1 outdoor locations but hand cleaning is preferred 2

For cable circuits installed in less hostile environments the amount of dust or other matter 3 collecting on the terminations (or around them) needs to be monitored on a regular basis to 4 help ensure the electrical clearances are not compromised Again the same cleaning methods 5 apply 6




Annex O 1

(informative) 2

Example for small substation 3

O1 General 4

This annex presents a typical distribution substation and steps through the process of designing 5 the cable system for it Typical values are used for this sample and are for illustration purposes 6 only 7

O2 Design parameters 8

Details of the substation are provided in Table O1 through Table O4 and in the one line 9 diagram (see Figure O1) Each circuit breaker is controlled remotely by an energy 10 management system (EMS) and locally from the control building An RTU is installed in the 11 control building and is connected to the EMS via the local phone company system Metering 12 data is obtained from the electronic protective relays (often referred to as intelligent electronic 13 devices or IEDs) 14

The control building is supplied as a prefabricated module with lighting receptacles fire 15 protection security heating air conditioning and ventilation All wiring for the control 16 building is specified by the supplier according to the NEC [B144] 17

AC supplies are also required for auxiliary circuits to outdoor lighting and power receptacles 18 for installation and testing equipment such as SF6 gas carts and transformer oil plants 19

Outdoor lighting consists of four 100 W high-pressure sodium (HPS) floodlights mounted on 20 equipment structures The four 100 W HPS floodlights will be supplied by two circuits each 21 with two of the floodlights (ie 200 W per circuit) 22

Outdoor receptacles will be provided at following two central locations 1) near the 23 transformers and 69 kV circuit breakers and 2) in the 12 kV equipment area The maximum 24 load expected for these receptacles is 240120 V 40 A 90 PF 25

Table O1mdash Site conditions 26

Parameter Value

Ambient temperature 0 degC to 40 degC Lightning activity Negligible

Earth conditions Dry soil

Table O2mdash Electric system parameters 27

Parameter HV LV

Nominal voltage phase to phase 69 kV 1247 kV Frequency 60 Hz 60 Hz

Maximum fault current three-phase rms 15 kA 10 kA




Table O3mdash Substation parameters 1

Parameter Value

DC system

Type 60 cell battery with charger Voltage 125 V (dc) nom 105 V (dc) EODa

Continuous load 5 A Fault level 1 kA

AC station service system

Type 1 phase 15 kVA Voltage 240120 V Load 15 kVA

Short-circuit level (ISC) 15 kA

Circuit breaker clearing time Maximum two cycles at ISC

Circuit breaker (69 kV and 1247 kV)

CTs 20005 A C400 20 Ω total burden Trip coil 10 A 90 V (dc) to 140 V (dc) Close coil 5 A 90 V (dc) to 140 V (dc) Alarms and status points 5

Spring charging motor 10 A run 24 A inrush 115 V (ac) plusmn10

AC load 60 W light 15 A receptacle 200 W heater

Transformer

Cooling fan motors 6 times 1 kW 230 V (ac) Alarm and status points 10

Control cabinet ac load 60 W light 15 A receptacle 200 W heater 120 V (ac)

Motor-operated disconnect switches (69 kV and 1247 kV)

Motor 2 A run 5 A inrush 125 V (dc) 90 V (dc) minimum

Cabinet heater 30 W at 120 V (ac) Status points 3

Voltage transformer

Secondaries Wye connected aEOD is the end of discharge which is used as the supply voltage for critical dc circuits 2

Table O4mdash Design parameters 3

Voltage drop criteria Value

DC supply voltage for critical circuits 105 V (dc) (EOD)a

DC supply voltage 116 V (dc)AC supply voltage 120240 V (ac)Feeders circuit voltage drop 3 maximumBranch circuit voltage drop 3 maximumOverall voltage drop 5 maximum

VT voltage drop 1 maximumaEOD is the end of discharge which is used as the supply voltage for critical dc circuits 4




1 Figure O1mdash One line diagram 2

O3 Select cables construction 3

O31 Conductor material 4

Refer to C11 5

Copper conductor will be used for all cables in this installation Conductors will be stranded The minimum 6 size for field cables will be 18 AWG for mechanical strength The minimum size for cables in the control 7 building will be 22 AWG 8

NOTEmdashFor conductor sizes 18 AWG and smaller the mechanical strength may be lower than required for pulling A larger 9 conductor size may be required to increase the mechanical strength for difficult pulling situations (eg long runs many bends) 10

O32 Insulation 11

Refer to C5 12

The cables will be installed in a dry environment with an ambient temperature up to 40 degC The cables will 13 be used both indoors and outdoors PVC conduit will be used outdoors for both above ground and below 14 ground installations Cable tray will be used indoors The PVC conduit in this example cannot be used with 15 cables having operating temperatures above 75degC This means that cables with a temperature rating up to 16




75degC may be used Those with a higher temperature rating may also be used but not at a temperature above 1 75degC 2

All equipment being wired is rated for 75 degC wiring 3

Various choices are available for this type of cable Cables with XLPE insulation and an overall PE jacket 4 will be used Color coding would be based on national standards or the utility companyrsquos standard 5

O33 Voltage rating 6

Refer to 432 and C51 7

The voltages used for the protection control and station service supplies are either 125 V dc or 120240 V 8 ac Voltage rating of either 600 V or 1000 V could be considered A cable voltage rating of 600 V will be 9 selected for this installation since the voltage rating is over twice the highest voltage used 10

O34 Shielding and grounding 11

Refer to 46 and Annex G 12

The voltage levels are 69 kV and 1247 kV There are no capacitors or high-voltage equipment (230 kV or 13 greater) in the station meaning there are no significant sources of EMI The lightning frequency is small 14 and can be ignored as an EMI source Based on this nonshielded cable will be used 15

O35 Number of conductors 16

Cables with 1 3 4 7 12 and 19 conductors are available for the project Cables with 22 AWG or smaller 17 conductors are available with 3 pair 6 pair or 18 pair 18

O4 Determine raceway routing 19

Refer to Annex F 20

The site is rectangular shape with equipment located by voltage level from high to low voltage and 21 symmetrical when multiple equipment devices are used (eg the two transformers are located adjacent to 22 each other) Refer to the site plan in Figure O2 The raceway design will be based on cost and practicality 23 Options considered include direct burial conduit tray and trench 24

The chosen raceway will consist of a main concrete cable trench with conduit runs to individual equipment 25 This results in short conduit runs that create few pulling problems and a main trench that is economical 26 The main trench also will accommodate future expansion of the substation The main trench will be located 27 away from the transformer For this substation 6 m (20 ft) was chosen to help avoid spewing oil Also the 28 cable trench will be located and the station sloped so oil spills do not flow into the cable trench 29

The routing to each piece of equipment is shown in Figure O3 The cable lengths from each piece of 30 equipment to the control building are listed in Table O5 31




1 Figure O2mdash Site plan 2




1 Figure O3mdash Cable routing plan 2

3

4




1

Table O5mdashCable lengths 2

Equipment

Length (See note)

m ft

Transformer no 1 (T1) 38 125 Transformer no 2 (T2) 34 112 69 kV circuit breaker (69CB1) 54 177 69 kV circuit breaker (69CB2) 52 171 69 kV circuit breaker (69CB3) 41 135 12 kV circuit breaker (12CB1) 33 109 12 kV circuit breaker (12CB2) 18 60 12 kV circuit breaker (12CB11) 36 119 12 kV circuit breaker (12CB12) 33 109 12 kV circuit breaker (12CB13) 21 68 12 kV circuit breaker (12CB14) 18 59 69 kV motor operated disconnect switch (69DT1) 47 154 69 kV motor operated disconnect switch (69DT2) 36 118 12 kV motor operated disconnect switch (12D3) 26 84 69 kV VT (69VT1) 50 164 69 kV VT (69VT2) 46 152 12 kV VT (12VT1) 31 103 12 kV VT (12VT2) 16 54 Station service supply no 1 (SST1) 30 100 Station service supply no 2 (SST2) 16 54 Receptacle no 1 (R1) 22 72 Receptacle no 2 (R2) 38 125 Floodlight no 1 (FL 1) 16 52 Floodlight no 2 (distance is between 1 and 2) (FL2) 28 92 Floodlight no 3 (FL3) 62 203 Floodlight no 4 (distance is between 3 and 4) (FL4) 28 92

NOTEmdashLengths from equipment terminal cabinet to control building are rounded to the nearest meter or foot and include allowance for leads at both ends of a run

3

O5 Cable sizing 4

O51 69 kV circuit breaker cables 5

Typically the same conductor sizes will be used for protection and control cables for all circuit breakers 6 AC and dc supply conductors are often larger and may be sized for each circuit breaker 7

O511 Trip coil cables 8

The same conductor size will be used for all circuit breakers The farthest circuit breaker is 54 m (176 ft) 9 away from the control building The battery voltage will be the end of discharge value of 105 V 10




O5111 Ampacity 1

Per Articles 310-15 and 220-10 of the NEC [B144] for a noncontinuous load the conductor ampacity will 2 be 100 of the rated current 3

Required ampacity = 10 A 4

Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient 5 temperature the smallest listed size is 14 AWG which has an ampacity of 176 A (adjusted for ambient 6 temperature) (Note that the over current protection for this conductor would be limited to 15 A per Article 7 2404(D) of the NEC [B144]) 8

NOTEmdashThe NEC ampacity is based on a continuous load Using the NEC tables for noncontinuous loads will result in conservative 9 sizing However ampacity is not usually the governing factor for cable selection and should not lead to over design 10

O5112 Voltage drop 11

Refer to C3 12

mdash The target voltage drop is 5 overall 13

Vdrop = 105 V plusmn 005 14

= 525 V 15

mdash Per unit length resistance for maximum circuit breaker cable length of 54 m (176 ft) at a 16 temperature of 75degC 17

Rac = 525 V10 A 18

= 0525 Ω 19

NOTEmdashThese conductors will be in nonmetallic conduits and Rdc = Rac for these smaller size conductors 20

mdash Using Equation (C6) 21

A = 34026 times (2 times 54 m) times [1 + 000393 (75degC ndash 20 degC)] times 102 times 104 0525 Ω at 22

75 degC 23

= 9030 cmil 24

The next size up commercial size is 10 AWG (10 380 cmil) 25

mdash Actual voltage drop for 10 AWG 26

Rdc = 3402610 380 cmil times [1 + 000393 (75 degC ndash 20 degC)] times 102 times 104 at 75 degC 27

= 39698 mΩm 28

Vdrop = 39698 mΩm times 54 mrun times 2 runs times 10 A 29

= 429 V 30




O5113 Short-circuit capability 1

Refer to C4 2 Short-circuit magnitude is 1 kA 3

Trip time for ISC is no more than two cycles (0033 s) for the equipment used This time varies 4

according to the specific equipment used 5

Short-time maximum conductor temperature is 250 degC per Table C8 (for XLPE or EPR) 6

Initial temperature is 75 degC 7

NOTEmdashThis is conservative Given a noncontinuous load it is unlikely that the conductor temperature will be this high 8 Justification could be made for using a lower temperature (eg ambient temperature) if this became a governing factor in 9 cable sizing 10

mdash Using Equation (C21) the minimum conductor size for short-circuit capability is 11

A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 12

A = 1000 (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 13

A = 2401 cmil 14 15

The next larger commercial size is 16 AWG (2580 cmil) 16

O5114 Cable selection 17

The minimum conductor size for ampacity voltage drop and short-circuit capability is 10 AWG The 18 resulting voltage drop for this conductor is 42 19

O512 Close coil 20

The same cable will be used for both the trip and close coils The conductor size of 10 AWG for the 10 A 21 trip coil current will be suitable for the 5 A close coil 22

The trip coil and close coil conductors will be in the same cable Trip coil monitoring is also being used in 23 this situation and will require one additional conductor A total of five conductors are required A seven- 24 conductor cable will be used allowing two spare conductors for future use 25

O513 Current transformers 26

The secondary circuit conductors for the CTs will be sized here The circuit breaker has CTs on both sides 27 of the circuit breaker that are rated 20005 A C400 for a total burden of 20 Ω resistance The same 28 conductor size will be used for all circuit breakers The farthest circuit breaker is 54 m (176 ft) away from 29 the control building 30




O5131 Ampacity 1

The CTs have a ratio of 20005 (ratio of 400) The maximum expected secondary current will be 086 A for 2 fully rated transformer load of 41 MVA (41000 kVA (radic3 x 69 kV x x 400) = 3431 A 400 = 086 A) 3

Per Article 220-10 of the NEC [B144] for a continuous load the conductor ampacity should be 125 of the 4 load 5

Required ampacity = 086 A times 125 = 11 A 6

Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient 7 temperature the smallest listed size is 14 AWG which has an ampacity of 176 A (adjusted for ambient 8 temperature) 9

O5132 Burden 10

The total burden for the CT circuit should be 20 Ω resistance or less to maintain its accuracy This will 11 include the burden of the CT winding the circuit conductors and relay(s) 12

mdash CT windings have a burden of approximately 00025 Ωturn For the CTs used on the circuit 13 breaker we have 14

Burden (CT) = 00025 Ωturn times 20005 turns 15

= 1 Ω 16

mdash The relay has a burden of 001 Ω 17

mdash The maximum allowable resistance of the secondary conductors is 18

Burden (cond) = 2 minus 1 minus 001 19

= 099 Ω 20


A = 34026times (2 times 54 m)099 Ω times [1 + 000393 (75 degC ndash 20 degC) ] times 102 times 104 at 22 75 degC 23

= 4789 cmil 24



Refer to C4 27

Short-circuit magnitude is 20 A (20 times full load current) 28




mdash Trip time is usually less than ten cycles but failure of a protection circuit could lead to a 1 duration of over 1 s For this calculation 2 s will be used 2

Short-time maximum conductor temperature is 250 degC per Table C8 3

mdash Initial temperature is 75 degC 4


A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 6

= 20 A (002972) log 10 [(250 + 2345)(75 + 2345)] 05 7

= 372 cmil 8

The next size up commercial size is 22 AWG (642 cmil) 9


The minimum conductor size for ampacity burden and short-circuit capability is 12 AWG 11

O514 Motor supply 12

The circuit breaker spring charging motor is operated at 115 V (ac) has a 10 A running current and a 24 A 13 inrush current The power factor is 90 and 25 for run and starting respectively 14

O5141 Ampacity 15



Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC 19 ambient temperature the smallest listed size is 14 AWG which has an ampacity of 176 A (adjusted for 20 ambient temperature) 21


Refer to C3 23


Vdrop = 120 V times 005 25

= 6 V 26

mdash Resistance at a temperature of 75 degC 27

Rac = 6 V 10 A 28




= 06 Ω 1

NOTEmdashThese conductors will be in nonmetallic conduits and Rdc = Rac 2


A = 34026 times (2 times 54 m)06 Ω times [1 + 000393 (75 degC ndash 20 degC)] times 102 times 104 at 4 75 degC 5

= 7901 cmil 6

The next size up commercial size is 10 AWG (10 380cmil) 7

mdash Check starting voltage 8

Rdc = 3402610 380cmil times [1 + 000393 (75 degC ndash 20 degC)] times 102 times 104 at 75 degC 9

= 42289 mΩm 10

Vdrop = IR cos θ 11

= 24 A times (42289 mΩm times 54 mrun times 2 runs) 12

= 110 V 13

Vmotor = 120 V ndash 110 V = 109 V 14

The motor starting voltage is above the minimum voltage of 1035 V (115 V ndash 10) 15


Refer to C4 17

Short-circuit level is 15 kA 18

mdash Short-time maximum conductor temperature is 250 degC per Table C8 19


NOTEmdashThis is conservative Given a noncontinuous load it is unlikely that the conductor temperature will be this high 21 Justification could be made for using the ambient temperature if this became a governing factor in cable sizing 22

mdash Clearing time typically two cycles (0033 s) 23


A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 25

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 3602 cmil 27 28






A conductor size of 10 AWG will satisfy ampacity voltage drop and short-circuit capability requirements 2 for the circuit breaker spring charging motor 3

O515 Auxiliary ac supply 4

The full load current is 173 A (15 A receptacle + 60 W + 200 W114 V) 5

O5151 Ampacity 6

The heaters will be assumed to be continuous loads and the light and receptacle noncontinuous loads For 7 ampacity 125 of continuous load and 100 of noncontinuous load will be used 8

Required ampacity = (150 W times 125)114 V + 15 A + (60 W114 V) = 172 A 9

A 20 A protective device is used to protect the circuit Per Table 310-15 (B)(16) and Section 2404(D) of 10 the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient temperature 10 AWG has an 11 ampacity of 308 A (adjusted for ambient temperature) 12


The conductor will be sized for voltage drop based on an 8 A load connected to the receptacle with a 14 unity power factor and both the heater and light on This gives a current of 103 A8 A + (60 W 15 + 200 W) 114 V 16

Refer to C3 17



= 60 V 20

mdash Per unit length resistance for maximum circuit breaker cable length of 54 m (176 ft) at a 21 temperature of 75 degC 22

Rac = 60 V103 A 23

= 0584 Ω 24

NOTEmdashFor this size of cable in non metallic conduit Rdc = Rac 25


A = 34026 times (2 times 54 m) times [1 + 000393(75 degC ndash 20 degC)] times 102 times 1040584 Ω at 27 75 degC 28

= 8118 cmil 29

The next larger commercial size is 10 AWG (10 380 cmil) 30




mdash Per unit resistance at a temperature of 75 degC 1

Rac = Rdc = 34026 times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 10380 cmil at 75 degC 2

= 42289 mΩm 3


Vdrop = 42289 mΩm times 54 mrun times 2 runs times 103 5

Vdrop = 47 V or 39 6


Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 16

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 3602 cmil 18



A 10 AWG conductor results in a voltage drop of 39 This conductor size also satisfies the minimum 21 size for ampacity and for short-circuit capability 22

O516 Alarm and status 23

Since the current in these conductors is small they will not be individually sized A 16 AWG conductor 24 will be used for these applications Five (5) status alarm and status points are required in this situation This 25 will require ten conductors A 12-conductor cable will be used providing two spare conductors for future 26 use 27




O52 Disconnect switch 1

O521 Motor supply 2

Motorized disconnect switches have a motor operator that uses 125 V (dc) has a 2 A run current and a 5 A 3 inrush current It may not be essential for the motors to be able to operate under all conditions (ie manual 4 operation may be possible even for motor operated disconnect switches) The disconnect switch motors are 5 not necessarily critical equipment and are expected to operate at the battery end of discharge voltage 6

O5211 Ampacity 7

The specified current is at the rated voltage of 125 V The normal expected battery voltage is 116 V 8 and equipment terminal voltage for a 5 voltage drop will be 110 V The current will then be 216 A 9 (2 A times 125 V110 V) 10





Refer to C3 18



= 58 V 21


Rac = 58 V 23 A 23

= 252 Ω 24



A = 34026 times (2 times 47 m) times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 252 Ω at 27 75 degC 28

= 1637 cmil 29






Refer to C4 2

mdash Short-circuit level is 10 kA 3






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 10

= 10000A (002970033) log10 [(250 + 2345)(75 + 2345)] 05 11

= 2401 cmil 12





Rdc = 340264110 cmil times [1+ 000393(75 degC ndash 20 degC)] times 102 times 104 at 75 degC 18

= 1068 mΩm 19


= 50 V 21

Vmotor = 116 V ndash 50 V 22

= 111 V 23

The motor starting voltage is above the minimum voltage of 90 V 24

O522 Status and alarms 25

Since the current in these conductors is small they will not be individually sized A 16 AWG conductor 26 will be used for these applications Three (3) position contacts are required in this situation This will 27 require six conductors A seven-conductor cable will be used providing one spare conductor for future use 28




NOTEmdashFor conductor sizes 16 AWG and smaller the mechanical strength may be lower than required for pulling Additional 1 conductor or a larger conductor size may be required to increase the mechanical strength of a cable 2


O5231 Ampacity 4

The heaters will be assumed to be continuous load 5

Required ampacity = (30 W times 125)114 V = 033 A 6

Per Table 310-15 (B)(16) and Article 2404(D) of the NEC [B144] for 75 degC conductor temperature and for 7 a 40 degC ambient temperature the smallest listed size is 14 AWG which has an ampacity of 176 A 8 (adjusted for ambient temperature) 9


Refer to C3 11



= 60 V 14

mdash Total circuit resistance for maximum cable length of 47 m (144 ft) at a temperature of 75 degC 15

Rac = 60 V033 A 16

= 228 Ω 17



A = 34026 times (2 times 47 m)228 Ω times [1+000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 20

= 181 cmil 21

The smallest size used for field cables is 18 AWG (1620 cmil) 22


Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 3

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 4

= 3602 cmil 5



A 14 AWG conductor is required to satisfy short-circuit capability The resulting voltage drop is 004 8

mdash Voltage drop for 14 AWG 9

Rac = Rdc 10

= 340264110 cmil times [1 + 000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 11

= 1068 mΩm 12


= 033 V or 028 14

O53 Transformer 15


The secondary conductors for the CTs will be sized here The power transformer has CTs on both the high- 17 voltage and low-voltage sides On the high-voltage side 20005 and 6005 CTs are used On the low- 18 voltage side 20005 CTs are used All CTs are C400 type which can have a total burden of 20 Ω 19 resistance 20

Conductors sized for the circuit breaker CTs will also be suitable for the power transformer CTs Per 21 O513 the minimum conductor size for ampacity burden and short-circuit capability is 12 AWG 22


Ten (10) status and alarm points are required for the power transformers This will require a total of 20 24 conductors Two 12-conductor cables will be used providing four spare conductors for future use 25


The power transformers have cooling fan motors with a total load of 6 kW at 240 V (ac) 95 PF The 27 control cabinet has 115 V (ac) loads consisting of a 60 W light a 15 A receptacle and a 200 W heater For 28 voltage drop the largest load would be at maximum temperature with the fans operating the light on and 29




an 8 A load connected to the receptacle It is assumed the cabinet heater would not operate when the fans 1 are operating 2

NOTEmdashThe 115 V loads are all on the same line but it is be possible to put the loads on different lines to reduce the peak load Also 3 each load has its own over current protection after the external terminal block 4

O5331 Ampacity 5

The load will be assumed to be continuous loads 6

Required ampacity = 6 kW230 V095 PF + (200 W + 60 W)115 V + 15 A times 125 = 559 A 7

Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC 8 ambient temperature 6 AWG with an ampacity of 572 A (adjusted for ambient temperature) is the 9 smallest suitable size 10


The conductor will be sized for voltage drop for a load of 6 kW230 V095 + 60 W115 V + 8 A = 36 A 12

Refer to C3 13



= 120 V 16


Rdc = Rac = 120 V 36 A 19

= 0332 Ω 20


A = 34026 times (2 times 38 m) 0332 Ω times [1+000393(75 degCndash20 degC)] times 102 times 104 at 22 75 degC 23

= 10 049 cmil 24



Refer to C4 27









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 4

= 15 kA (002970033) log10 [(250 + 2345) (41 + 2345)] 05 5

= 3602 cmil 6

The next larger commercial size remains 14 AWG (4110 cmil) 7


A 6 AWG conductor is required for ampacity Based on this conductor size the voltage drop will be 17 9


Rac = Rdc = 3402626240 cmil times [1+000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 11

= 1673 mΩm 12


= 517 V or 225 14

O54 Voltage transformers 15

The secondary conductors for the VTs will be sized for steady-state operation The VT secondaries are 16 connected wye giving a voltage of 120 Vradic3 or 6928 V The VTs have a maximum allowable burden of 75 17 VA at 85 PF The same conductor size will be used for all VTs The farthest VT is 50 m (148 ft) away 18 from the control building 19

O541 Ampacity 20


Required ampacity = 75 VA times 125120 V radic3 = 045 A 23



Refer to C3 Designing to the maximum burden will not provide for accurate voltages at the relay Voltage 28 drop will be the design parameter and the total burden will be verified to be below the maximum 29




mdash The target voltage drop is 1 for high accuracy 1


= 069 V 3

mdash Conductor resistance for a balanced system voltage maximum burden and a temperature 4 of 75 degC 5

Rdc = Rac = 069 V 036 A 6

= 192Ω 7



A = 34026 times 50 m) 131 Ω [1+ 000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 10

= 1675 cmil 11



The short-circuit capability of a VT is low and does not need to be considered 14


The minimum conductor size for ampacity and voltage drop is 14 AWG Allowing 01 A for relay burden 16 (electronic relays have burdens in the order of 02 VA) the total burden will be 82 VA less than the 17 75 VA maximum 18


Rac = Rdc = 34026 4110 cmil times [1 + 000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 20

= 1068 mΩm 21

Burden = (1068 mΩm times 50 m times (01 A 085 PF)2) + (693 V times 01 A 085 PF) = 82 VA 22

O55 Station service supply 23

The two station service supplies have a 15 kVA capacity Only one is used to supply the load at a time The 24 total connected load with allowance for additional equipment in the future is 10 kW with an average power 25 factor of 90 26

O551 Ampacity 27

Required ampacity = (15 kVA times 125) 230 = 815 A 28




Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient 1 temperature the smallest suitable size is 3 AWG which has an ampacity of 88 A (adjusted for ambient 2 temperature) 3

O552 Voltage drop 4

Load for voltage drop will be 10 kW at 90 PF or 483 A 5

The transformer taps will be adjusted to provide a voltage of approximately 120 V at the service panel The 6 transformer has four taps of 125 each Voltage drop will be calculated for the 3 AWG conductor 7 required for ampacity 8


Rac = Rdc = 34026 52620 cmil times [1+ 000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 10

= 08342 mΩm 11


= 31 V or 13 13

Setting the transformer tap at +125 will result in a service panel voltage of 2399 V (240 times 10125 14 ndash 31 V) 15


Refer to C4 17






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 23

= 15 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 24

= 3602 cmil 25



A 3 AWG conductor satisfies the minimum size for ampacity and short-circuit capability The transformer 28 taps will be used to adjust the voltage to the required level 29




This conductor size 3 AWG may not be readily available If not it could be special ordered or 1 alternatively the next larger size could be used In this case the next larger size of 2 AWG conductor was 2 selected 3

O56 Outdoor lighting 4

The four floodlights will be supplied by two circuits each supplying two of the floodlights High power 5 factor ballasts with a 90 PF will be used Two voltage drop philosophies may be used placing the total 6 load at the farthest point or placing the load at their actual locations The first method simplifies 7 calculations while the second method requires more calculations but is more accurate The first method 8 will be used because for a small load voltage drop will likely not be the governing factor for cable sizing 9

O561 Ampacity 10

Required ampacity = (2 times 100 W times 125) 09 115 V = 242 A 11


O562 Voltage drop (for circuit supplying FL3 and FL4) 15

Load for voltage drop will be 200 W at 90 PF or 193 A 16



= 60 V 19


Rac = 60 V 193 A 21

= 2795 Ω 22

mdash Using Equation (C5) the distance to FL4 is 90 m (62 m + 28 m) 23

A = 34026 times 90 m times 2) 2795 Ω times [1+ 000393(75 degCndash20 degC)] times 102 times 104 at 24 75 degC 25

= 2827 cmil 26

27 The next larger commercial size is 14 AWG (4110 cmil) 28


Refer to C4 30









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 6

= 15 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 7

= 3602 cmil 8



Ampacity is the governing factor for this cable and requires a 14 AWG The resulting voltage drop is 11 464 12



= 1068 mΩm 15


= 464 V or 386 (464120 times 100) 17

O57 Outdoor receptacles 18

The two outdoor 50 A receptacles will be provided The largest full load current for equipment that will be 19 used with the receptacles is 40 A at 90 PF The cables will be sized for receptacle R2 and the same size 20 cable will also be used for R1 21

O571 Ampacity 22


Per Table 310-15 (B)(16) of the NEC [B144] f for 75 degC conductor temperature and for a 40 degC ambient 24 temperature the smallest suitable size is 3 AWG which has an ampacity of 792 A (adjusted for ambient 25 temperature) 26


Load for voltage drop will be 40 A09 = 444 A 28






= 120 V 3


Rac = 120 V 444 A 5

= 027 Ω 6


A = 34026 times 38 m times 2) 027 Ω times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 8 75 degC 9

= 12 356 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 15 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 20

= 3602 cmil 21



Ampacity is the governing factor for this cable and requires a 3 AWG conductor This conductor size (3 24 AWG) may not be readily available If not it could be special ordered or the next larger size could be 25 used In this case the next larger size (2 AWG) conductor was selected 26

O58 Supervisory control and data acquisition cables 27

The cable selections for the SCADA system are shown in Figure O4 In this system the IEDs collect 28 substation data through the control VT and CT cables routed from the substation equipment These cables 29




are sized and routed in accordance with the corresponding sections of this example and are not discussed in 1 further detail here For the SCADA components however all cables are located entirely within the control 2 building and are routed only from one component to the next All currents are on the order of a few 3 milliamps and a very small conductor size of 22 AWG or 24 AWG is sufficient Note that the physical 4 strength of the cable should be taken into account at these small sizes In this example the slightly larger 22 5 AWG is used for longer routes while the smaller 24 AWG is used for shorter routes 6

Remote PC

Modem

4 Wire Phone Cable

EMS Master Station

Modem

4 Wire Phone Cable

Port Switch

22 AWG

Dia

l -u

p C

ircu

it

Ded

ica

ted

C

ircu

it

Remote Terminal Unit (RTU) CPU

22 AWG

22 AWG

HUBCAT5Ethernet

HMI PCNIC

NIC

CAT5Ethernet

Communications interface

22 AWG

StatusAnn Module (Digital Inputs)

22 AWG

Analog Module (Analog Inputs)

22 AWG

Control Module (Control Outputs)

Interpose Relays

24 AWG

Interpose Relays

24 AWG

RS232RS485 Communications Interface Converter

22 AWG

IED IED IED

24 AWG 24 AWG

Control PT ampCT Cables

Substation Equipment Yard



24 AWG

22 AWG

22 AWG

7 Figure O4mdash SCADA cable selection 8

There are two communications circuits needed In this example there is one circuit to the EMS Master 9 Station and one accessible from a remote site such as an office computer or laptop Given the high 10 criticality of the EMS circuit it should be dedicated Since the remote site circuit will only be accessed 11 periodically a dial-up circuit is sufficient A port switch on the dial-up circuit allows one phone line to be 12 used by several devices including the IEDs A communications processor device could also be used 13




The manufacturer typically standardizes the connections between the RTU and the peripheral modules In 1 this example these cables would be ordered directly from the manufacturer Typically a small conductor 2 such as 22 AWG is used 3

In this example the utility desires to connect the onsite HMI to the RTU through the utilityrsquos LAN 4 connection at the substation This connection requires an Ethernet hub as well as network interface cards 5 (NICs) in both CPUs Category 5 cable is standard and is used in this case A serial connection can also be 6 used if LAN access is not available 7

Finally the communications interfaces for all devices should be considered Many IEDs provide an RS485 8 interface while the RTU is typically RS232 Therefore an interface converter is installed to connect the 9 IEDs to the RTU 10

O59 Cable summary 11

Table O6 summarizes the field cables used for each type of equipment Note that cables will not be run for 12 CT or VT windings that will not be used initially 13

Table O6mdashEquipment cable summary 14

Equipment

Total number

of cables

Cables (qty x type)

Transformer no 1 (T1) 6 2times12C16 1times2C6 3times4C12 Transformer no 2 (T2) 6 2times12C16 1times2C6 3times4C12 69 kV circuit breaker (69CB1) 6 1times10C16 1times2C12 1times2C10 2times4C14 1times7C1069 kV circuit breaker (69CB2) 6 1 times10C16 1 times2C12 1times2C10 2times4C14 1 times7C1069 kV circuit breaker (69CB3) 7 1times10C16 1times2C12 1times2C10 3times4C14 1times7C1012 kV circuit breaker (12CB1) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1012 kV circuit breaker (12CB2) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1012 kV circuit breaker (12CB11) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1012 kV Circuit Breaker (12CB12) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1012 kV Circuit Breaker (12CB13) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1012 kV Circuit Breaker (12CB14) 5 1times10C16 1times2C12 1times2C10 1times4C14 1times7C1069 kV motor operated disconnect switch (69DT1) 3 1times7C16 1times2C12 1times2C10 69 kV motor operated disconnect switch (69DT2) 3 1 times7C16 1 times2C12 1 times2C10 12 kV motor operated disconnect switch (12D3) 3 1times7C16 1times2C12 1times2C10 69 kV VT (69VT1) 1 1times4C14 69 kV VT (69VT2) 1 1times4C14 12 kV VT (12VT1) 1 1times4C14 12 kV VT (12VT2) 1 1times4C14 Station service supply no 1 (SST1) 1 1times3C2 Station service supply no 2 (SST2) 1 1times3C2 Outdoor lighting 2 2times2C12 Outdoor receptacles 2 2times3C2

O6 Design cable raceway 15

The raceway will consist of a combination of in-ground trenches and PVC conduit runs to individual pieces 16 of equipment See Table O7 for details 17




O61 Redundant cable requirement 1

No redundant cables are required for this installation since the consequences of equipment damage or 2 system reliability is determined not severe 3

O62 Electrical segregation 4

The voltage levels used do not require any electrical segregation Protection and control cables typically 5 have no or minimal constant current flowing in them As a result it is not customary to apply derating 6 factors for the presence of adjacent cables However the main ac station service cables will have 7 continuous current flow Adjacent cables would then need to be derated due to the mutual heating For this 8 reason it would be desirable to have separate routes for these cables 9

O63 Raceway sizing 10

The number and size of all cables going to each piece of equipment was used to prepare Table O7 The 11 ultimate cable area was based on having cables for all CT or VT secondary windings Spare capacity 12 allowances above that for the ultimate cable area will be provided For this project the spare capacity 13 allowance has been chosen to be 25 for individual conduits and 50 for the two main trenches The 14 conduit sizes were selected based on conduit fill requirements of the NEC [B144] 15

A sample calculation conduit fill calculation is given for T1 16

Ultimate cable area 1377 mm2

Cable area with 25 spare capacity 1721 mm2 (1377 mm2 times 125)

Allowable conduit fill for seven cables 40

Required conduit area 4303 mm2 (1721 mm2 04)

Duct diameter 74 mm (d = 2radic4303pi)

Duct size selected 75 mm (3 in) 17

Most conduit raceways are straight runs with a 90deg bend from the cable trench and a 90deg bend to the 18 equipment A few conduit raceways have an additional bend between the ends but the total bending 19 degrees does not exceed the recommended 270deg 20

A minimum bending radius of 12 times the cable OD will be used The largest cable has a diameter of 25 21 mm giving a minimum conduit radius of 300 mm (25 mm times 12) PVC conduit bends are available with a 22 range of radii with 450 mm (1 8 in) 600 mm (24 in) and 900 mm (36 mm) being common Bends with a 23 450 mm radius will be used for this project and satisfies the minimum bending radius 24

Table O7mdashSummary of raceway sizes 25

Raceway section Initial cablearea (mm2 )

Ultimate cable area (mm2)

Selected raceway size

Trench 1 14046 15906 450 mm times 75 mm Trench 2 6719 7593 250 mm times 75 mm Conduit to T1 1264 1377 75 mm duct Conduit to T2 1264 1377 75 mm duct




Conduit to 69CB1 912 1025 75 mm duct Conduit to 69CB2 912 1025 75 mm duct Conduit to 69CB3 1025 1138 75 mm duct Conduit to 12CB1 912 1025 75 mm duct Conduit to 12CB2 912 1025 75 mm duct Conduit to 12CB11 912 1025 75 mm duct Conduit to 12CB12 912 1025 75 mm duct Conduit to 12CB13 912 1025 75 mm duct Conduit to 12CB14 912 1025 75 mm duct Conduit to 69DT1 517 517 50 mm duct Conduit to 69DT2 517 517 50 mm duct Conduit to 12D3) 517 517 50 mm duct Conduit to 69VT1 154 308 50 mm duct Conduit to 69VT2 154 308 50 mm duct Conduit to 12VT1 154 308 50 mm duct Conduit to 12VT2 154 308 50 mm duct Conduit to SST1 515 515 50 mm duct Conduit to SST2 515 515 50 mm duct Conduit to R1 515 515 50 mm duct Conduit to R2 515 515 50 mm duct Conduit to FL1 131 131 25 mm duct Conduit FL1 to FL2 131 131 25 mm duct Conduit to FL3 131 131 25 mm duct

Conduit FL3 to FL4 131 131 25 mm duct

O64 Cable installation 1

A sample calculation is shown for the ldquoConduit to T1rdquo and values for other conduits are summarized in 2 Table O9 3

O641 Maximum pulling tension 4

The maximum tension is calculated using Equation (J1) and Equation (J2) A general version of these 5 equations is shown in Equation (O1) to determine the minimum effective area when multiple sizes of 6 cables are pulled within the same raceway 7

Tmax = K f n A 8 = K Aeff (O1) 9

where 10

f is 1 0 for one or two cables and 06 for three or more cables 11 n is the number of cables per size 12 A is the total area of each size 13 Aeff is the total effective area for multiple conductors in a cable or combined cable sizes 14 15

The cables to T1 are 2times12C16 1times2C6 and 3times4C12 (see Table O6) Aeff for each conductor size is 16 summarized in Table O8 17




Table O8mdashAeff for different cable sizes 1

Cables Conductors n Conductor size

(cmil) Total area A

(cmil) f

Aeff (cmil)

2 12 2 580 (16 AWG) 61 920 10 61 920 1 2 26 240 (6 AWG) 52 480 10 52 480

3 4 6 530 (12 AWG) 78 360 06 47 016

2

The minimum effective area (Aeff) is 47 016 cmil The maximum pulling tension (note area was changed to 3 kcmil) is determined by using Equation (O1) as follows 4

Tmax = 356 Nkcmil times 47016 kcmil 5

= 1673 = 17 kN (376 lb) 6

NOTEmdashAn alternate method of determining the minimum effective area is to total the area for all cables and then use a percentage 7 between 50 and 20 The cable manufacturer should be consulted on their recommendation if this method is used 8

A basket grip will be used to pull the cables The recommended maximum tension is 445 kN which is 9 above the calculated maximum tension of 17 kN 10

O642 Jam ratio 11

Cable jamming may occur due to wedging of cables in the raceway For the cables being pulled for 12 T1 there are three cables of the same diameter 13

Duct diameter = 75 mm 14

Cable diameter = 12 mm (4C12 AWG) 15

Dd = 7512 = 625 16

Since the ratio is above 30 jamming will not be a concern 17

O643 Pulling tension 18

The raceway route from the main cable trench to T1 consists of the following (see Figure O3) 19

Section 1 Vertical bend down 90deg 450 mm radius 20

Section 2 Straight run 38 m long 21

Section 3 Horizontal bend 90deg 450 mm radius 22

Section 4 Vertical bend up 90deg 450 mm radius 23

Some situations may permit the cables to be pulled from either end and the tension would be calculated for 24 pulling both ways In this case the cable will be laid in the trench and then pulled through the duct 25

The cables will be pulled through PVC duct The coefficient of friction K is 05 for unlubricated duct and 26 02 for lubricated duct Lubrication will be used so K is 02 27




O6431 Section 1 1

There may be an incoming tension if the cable is being pulled off reels In this example the cable is 2 coming from a trench and it is anticipated that the cable would have been pulled into the trench and fed 3 into the duct with rollers The incoming tension will initially be the total mass of the cable length being 4 pulled and it will gradually decrease as the cables are pulled into the raceway The highest tension occurs 5 near the end of the pull when the initial tension will be near zero The initial tension will be assumed to 6 be the remaining length that needs to be pulled in or the length of cable extending beyond the last bend 7 to reach the termination point This length is approximately 3 m (06 m for the bend and 2 m to reach above 8 ground) 9

Tin = m g 10

= 3 m times 17 kgm times g 11

= 50 N 12

Equation (J15) may be used provided the incoming tension is greater than or equal 10 Wr The initial 13 tension of 50 N is greater than 10Wr (77 in this case) so the simplified formula may be used 14

Tout = Tine fcθ 15

For this case 16

f = 02 17

c = 132 (for six cables with Dd of 35) 18

θ = π2 radians 19

Tout = 50 e(02)(132)(π 2) 20

= 50 e041 21

= 757 N 22

O6432 Section 2 23

The pulling tension in a straight raceway is calculated according to Equation (J9a) 24

Tout = Tin + Lmgfc 25

For this case 26

L = 38 m 27

m = 17 kgm 28 g = 98 ms2 29

f = 02 30 c = 132 (for 6 cables with Dd of 35) 31




Tout = 757 N + 38 m times 17 kgm times 98 ms2 times 02 times 132 1

= 757 + 1673 N 2

= 243 N 3

O6433 Section 3 4

The simplified equation for calculating the pulling tension in horizontal bend is Equation (J 15) 5

Tout = Tin e fcθ 6

For this case 7

f = 02 8

c = 132 (for six cables with Dd ofrsquo 35) 9

θ = π2 radians 10

Tout = 243 e(02)(132)(π 2) 11

= 243 e041 12

= 3679 N 13

O6434 Section 4 14

The simplified equation for calculating the pulling tension in vertical bend is Equation (J15) 15

Tout = Tin efcθ 16

For this case 17

f = 02 18


θ = π2 radians 20

Tout = 3679 e(02)(132)(π 2) 21

= 3679 e041 22

= 557 N 23

This is below the maximum pulling tension of 41 kN If it was above the maximum pulling tension 24 options to reduce the pulling tension are to change the raceway design or reduce the coefficient of 25 friction 26

In this case eliminating Section 3 can be done very easily by angling the raceway between the end 27 points The maximum pulling tension would then be reduced to 368 N in this case 28




O644 Sidewall bearing pressure 1

The maximum allowable sidewall bearing pressure (SWBP) for cables 8 AWG and smaller is 4380 Nm of 2 radius (300 lbfft of radius) For more than four cables the formula becomes more complicated The 3 cables may be assumed to form a cradle form in the bend and the two bottom cables will share the load 4 equally Using Equation (J7) 5

SWBP = c times Tmax2R 6

= 132 (17 kN)(2 times 045 m) 7

= 2494 kNm 8

The maximum allowable SWBP is acceptable 9


Results for all raceways are given in Table O9 The pulling tension is below the maximum for all runs 11 except those to 69CB1 and 69CB2 In these cases one bend in the run can be eliminated by angling the 12 ducts between the end of the trench and the circuit breaker When this is done the pulling tensions reduce 13 to 033 kN and 03 kN for 69CB1 and 69CB2 respectively With these changes the pulling tensions are 14 acceptable for all cables 15

Table O9mdash Summary of cable installation parameters 16

Raceway section Numberof cables

Maximumpulling

tension (kN)

Total cable mass (kgm)

Pulling tension

(kN)

Conduit to T1 6 17 170 056 Conduit to T2 6 17 170 052 Conduit to 69CB1 5 05 104 050 Conduit to 69CB2 5 05 104 046 Conduit to 69CB3 6 05 126 031 Conduit to 12CB1 5 05 104 022 Conduit to 12CB2 5 05 104 015 Conduit to 12CB11 5 05 104 023 Conduit to 12CB12 5 05 104 022 Conduit to 12CB13 5 05 104 017 Conduit to 12CB14 5 05 104 015 Conduit to 69DT1 3 05 048 019 Conduit to 69DT2 3 05 048 016 Conduit to 12D3 3 05 048 009 Conduit to 69VT1 1 06 017 005 Conduit to 69VT2 1 06 017 004 Conduit to 12VT1 1 06 017 003 Conduit to 12VT2 1 06 017 002 Conduit to SST1 1 71 148 037 Conduit to SST2 1 7 1 1 48 028 Conduit to R1 1 7 1 1 48 024 Conduit to R2 1 71 148 035 Conduit to FL1 1 05 013 002




Conduit between FL1 and FL2 1 05 013 002 Conduit to FL3 1 05 013 004

Conduit between FL3 and FL4 1 05 013 002

1




Annex P 1

(informative) 2

Example for large substation 3

P1 General 4

This annex presents a typical transmission substation and steps through the process of designing the cable 5 system for it Typical values are used for this sample and are for illustration purposes only 6

P2 Design parameters 7

Details of the substation are provided in Table P1 through Table P4 and in the one line diagram (see 8 Figure P1) Each power circuit breaker is controlled remotely by an energy management system (EMS) 9 and locally from the control building Transformer T1 power control CTs alarm and indication is via 10 copper cables Alarm and indication for Transformer T2 is via fiber optic cable Control indication and 11 CTs for the 345 kV power circuit breakers is via copper control cables Relay communications for the 345 12 kV transmission lines is by fiber optic cables and power line carrier Control and indication for 138 kV 13 power circuit breakers is via fiber optic cables CTrsquos for the 138 kV power circuit breakers are via copper 14 control cables The 138 kV capacitor banks are switched back to back with power circuit breakers 15 Metering data is obtained from the electronic protective relays (often referred to as intelligent electronic 16 devices or IEDs) 17

Substation equipment network communications is depicted in Figure P4-Communications cable diagram 18 SCADA communications to the utility WAN is provided by microwave and fiber optic networks A 19 SCADA RTU is installed in the control building and is connected to the EMS via the utility microwave 20 system Large bulk transmission stations require redundant communication and protection systems to meet 21 operating compliance which will be provided by microwave communications in this example 22

The control building is supplied with lighting receptacles fire protection security heating air 23 conditioning and ventilation All wiring for the control building is specified according to the NEC [B144] 24

AC panels are located inside the control building and supply power for auxiliary circuits such as outdoor 25 lighting power receptacles for testing equipment SF6 gas carts and transformer cooling systems 26

Outdoor lighting consists of forty 100 W high-pressure sodium (HPS) floodlights mounted on equipment 27 structures The forty 100 W HPS floodlights will be supplied by ten circuits each with three to five of the 28 floodlights (ie 400 W per circuit) For the purposes of this example the use of HPS floodlights were 29 selected over newer LED technology as HPS floodlights are more common 30

Outdoor receptacles will be provided at following locations 1) near the transformers and the 15 kV area 31 and 2) in the 345 kV and 138 kV equipment areas The maximum load expected for these receptacles is 32 208120 V 40 A 90 PF 33




Table P1mdashSite conditions 1

Parameter Value

Ambient temperature -40 degC to 50 degC

Lightning activity Low


Control building MICE classification M1I1C1E3

Outdoor MICE classification M1I3C2E3

Table P2mdashElectric system parameters 2

Parameter HV LV TV

Nominal voltage phase to phase 345 kV 138 kV 138 kV

Frequency 60 Hz 60 Hz 60 Hz

Maximum fault current three-phase rms 40 kA 20 kA 10 kA

Table P3mdashSubstation parameters 3

Parameter Value

DC system

Type 60 cell battery with charger

Voltage 125 V (dc) nom 105 V (dc) EOD a

Continuous load 25 A

Fault level 3 kA


Type 3 phase 500 kVA

Voltage 208120 V

Load 500 kVA



Circuit breaker (345 kV)




Parameter Value

CTs (6 sets) 20005 A C800 40 Ω total burden

Trip coil 35 A per pole 70 V (dc) to 140 V

(dc) 105 A Total

Close coil 35 A per pole 90 V (dc) to 140 V

(dc) 105 A Total

Alarms and status points 12

Spring charging motor 120 V (ac) at 16 A per pole

125 V(dc) 10 48 A Total

AC load 60 W light 15 A receptacle

tank heaters 38 A

cabinet heaters 1140 W 208 V(ac)



Trip coil 35 A per pole 125 V (dc) 10

Close coil 35 A per pole 125 V (dc) 10


Spring charging motor 128 A run 125 V (dc) 10

134 A run 120 V(dc)

AC load 60 W light 15 A receptacle tank

heaters 38 A space heat 120 V(ac)

300 W tank heater 208 V(ac)


CTs (2 sets) 30005 A C800 RF8

12005 A C400 RF133

Trip coil Trip 1 59 A 125 V(dc) 10

Inrush 21 Ω




Parameter Value

Trip2 170 A 125 V(dc) 10

Inrush 20 Ω

Close coil 28A 125 V(dc) 10

Inrush 883 Ω


Spring charging motor 10A run 120 V(dc) 10


heaters 300 W 208 V(ac)

Transformer

CTs High 12005 C800

Low 20005 C800

Tertiary 30005 C800

Cooling fan motors

12 746 W 208 V(ac)

FLC 32 ALRC 1109 A

Alarm and status points 12

Control cabinet ac load 50 W light 20 A receptacle

2000 W heater 208 V(ac)


Motor 2 A run 5 A inrush 125 V(dc)

90 V(dc) minimum

Cabinet heater 30 W 120 V(ac)

Status points 3

Voltage transformer

Secondaries Wye connected

a EOD is the end of discharge which is used as the supply voltage for critical dc circuits 1




Table P4mdashDesign parameters 1


DC supply voltage for critical circuits 105 V(dc) (EOD) a

DC supply voltage 116 V(dc)

AC supply voltage 120208 V(ac)

Feeders circuit voltage drop 3 maximum

Branch circuit voltage drop 3 maximum

Overall voltage drop 5 maximum

VT voltage drop 1 maximum


3 Figure P1mdashOne line diagram 4




P3 Select cables construction 1

P31 Conductor material 2

P311 Multiconductor Control Cable 3

Refer to C11 4

Copper conductor will be used for all multiconductor control cables in this installation Conductors will be 5 stranded The minimum size for field cables will be 18 AWG for mechanical strength The minimum size 6 for cables in the control building will be 22 AWG 7

NOTEmdashFor conductor sizes 18 AWG and smaller the mechanical strength may be lower than required for pulling A larger 8 conductor size may be required to increase the mechanical strength for difficult (eg long runs many bends) pulling situations 9

P312 Power cable (lt1 kV) 10

Refer to Clause 7 11

Copper conductor will be used for all power cables in this installation Conductors will be stranded The 12 minimum size for field cables and control building will be 12 AWG for mechanical requirements 13

P313 Power cable (15 kV) 14


Copper conductor will be used for all 15 kV power cables in this installation Conductors will be stranded 16 The minimum size for power cables will be 8 AWG for mechanical requirements 17

P314 Fiber optic cable 18


P315 Communications cable 20


P32 Insulation 22

P321 Multiconductor control cable 23

Refer to C5 24

The cables will be installed in a wet environment with an ambient temperature range between -40 degC and 25 50 degC The cables will be used both indoors and outdoors PVC conduit will be used outdoors for both 26 above ground and below ground installations Cable tray will be used indoors 27




All equipment being wired is rated for 75 degC operating temperature 1

Cables with XLPE insulation and an overall CPE jacket will be used Color coding would be based on 2 national standards or the utilityrsquos standard 3


Refer to Clause 7 5

The power cables will be installed in a wet environment with an ambient temperature range between -40 degC 6 and 50 degC The cables will be used both indoors and outdoors PVC conduit will be used outdoors for both 7 above ground and below ground installations Cable tray will be used indoors The temperature rating of 8 the PVC conduit may limit the temperature rating andor quantity of the cables to be installed in the 9 raceway For this example the PVC conduit is rated for 90 degC 10


Various choices are available for this type of cable Ethylene Propylene Rubber (EPR) is more flexible and 12 easier to handle Suitable for low-voltage and medium-voltage applications and resistant to the growth of 13 water trees Cables with CPE insulation and an overall CPE jacket will be used Color coding would be 14 based on national standards or the utilityrsquos standard 15



The 15kV power cables will be installed in a wet environment with an ambient temperature range between 18 -40 degC and 50 degC The cables will be routed and used outdoors PVC conduit will be used for both above 19 ground and below ground installations The temperature rating of the PVC conduit may limit the 20 temperature rating andor quantity of the cables to be installed in the raceway For this example the PVC 21 conduit is rated for 90 degC 22


The selection of insulation for power cables is one of the most important components of the cable Various 24 choices of insulation are available for this type of cable that vary in their dielectric properties resistance to 25 high temperature and moisture mechanical strength flexibility and long life Ethylene Propylene Rubber 26 (EPR) is flexible and relatively easy to handle Itrsquos also suitable for medium-voltage applications (through 27 69kV) and resistant to the growth of water trees Cables with CPE insulation and an overall CPE jacket 28 will be used Color coding would be based on national standards or the utilityrsquos company standard 29



P33 Voltage rating 32





The voltages used for the protection control and station service supplies are either 125 V(dc) or 120208 1 V(ac) Voltage rating of either 600 V or 1000 V could be considered A cable voltage rating of 600 V will 2 be selected for this installation since the voltage rating is over twice the highest voltage used 3

The choice of cable insulation can be 100 133 or 173 of the rated system voltage In order to 4 determine the appropriate voltage level for the medium voltage cable one should consider the voltage level 5 of the system and responsiveness to ground faults The primary voltage for the station service transformer 6 is 138 kV and protected by high-side fuses and lower-side circuit breakers The cable for the 138 kV 7 station service will be 15 kV class with insulation rated for 133 of the system voltage 8

P34 Shielding and grounding 9

Refer to 46 Annex F and Annex G 10

The 345 kV voltage level requires the use of shielded multiconductor control cable for the 345 kV 11 equipment The back to back switched capacitors also require the use of shielded multiconductor cable due 12 to their source of EMI The lightning frequency is small and can be ignored as an EMI source While most 13 of the 138 kV equipment does not require shielded cable the cables near the capacitor banks should be 14 shielded due to potential interference from switching transients For uniformity and cost considerations 15 shielded multiconductor cable will be used for all yard equipment multiconductor control cables 16

Power cables rated at 24kV and higher will use both a conductor shield and an insulation shield The 17 conductor shield will prevent excessive voltage stresses in the voids between the conductor and the 18 insulation The insulation shield should also provide a low-impedance ground fault current path for 19 protective devices The conductor shield and insulation shield together will confine the dielectric field 20 within the cable and help smooth out the voltage stress along and around the cable Both shields will be 21 grounded at both ends to improve the reliability and safety of the circuit 22

P35 Number of conductors 23


Cables with 2 3 4 7 and 12 conductors are available for the project Cables with 22 AWG or smaller 25 conductors are available with 3 pair 6 pair or 18 pair 26


Cables with 2 and 3 conductors are available for the project 28


Power cables 15 kV and above will be single conductor 30

P4 Determine raceway routing 31

Refer to Annex F 32

The site is square with equipment located by voltage level from high to low voltage and symmetrical when 33 multiple equipment devices are used (eg 345 kV equipment yard transformers centrally located 138 kV 34




equipment yard) Refer to the site plan in Figure P2 The raceway design will be based on cost and 1 practicality Options considered include direct burial conduit tray and trench 2

The chosen raceway will consist of main concrete cable trenches with conduit runs to individual 3 equipment This results in shorter conduit runs that create fewer pulling problems and a main trench system 4 that is economical 5

The routing to each piece of equipment is shown in Figure P3 The cable lengths from each piece of 6 equipment to the control building are listed in Table P5 15 kV power cables for station service will be 7 routed independent of the trench system between the station service structures and the station service 8 transformers 9

10 Figure P2mdash Site plan 11




1 Figure P3mdash Cable routing plan 2

3




1

Table P5mdashCable lengths 2

Equipment

Length

(See NOTE)

(m) (ft)

Microwave Tower (MWT) 15 49

Transformer No 1 (T1) 87 285


Station Service Transformer No 1 (SST1) 60 197


345kV Circuit Breaker (345CB1) 88 289






345kV CCVT (345CCVT1) 82 269

345kV CCVT (345CCVT2) 52 171

345kV CCVT (345CCVT3) 81 266

345kV CCVT (345CCVT4) 75 246

345kV Line 1 Fiber (FO JB5) 53 174


345kV Line 3 PLC Line Tuner Coax (LT1) 52 171


345kV Reactor (345REA1) 155 509

138kV Capacitor Bank (138CAP1) 136 446





Equipment

Length

(See NOTE)

(m) (ft)

138kV Motor Operated Switch (138MOS1) 90 295


138kV Current Transformer (138CT1) 179 587
















138kV CCVT (138CVT1) 88 289

138kV CCVT (138CVT2) 82 269

138kV CCVT (138CVT3) 76 249

138kV CCVT (138CVT4) 70 230

138kV CCVT (138CVT5) 52 171

138kV CCVT (138CVT6) 45 148




Equipment

Length

(See NOTE)

(m) (ft)

138kV CCVT (138CVT7) 40 131

138kV CCVT (138CVT8) 33 108

138kV CCVT (138CVT9) 60 197

138kV CCVT (138CVT10) 76 249

15kV VT (15VT1) 61 200

15kV VT (15VT2) 55 180



Floodlight (FL1) 5 16



















Equipment

Length

(See NOTE)

(m) (ft)




























Equipment

Length

(See NOTE)

(m) (ft)

Yard Outlet 1(YOUT1) 61 200


DC Panel Main 5 16

AC Panel Main 10 32

NOTEmdashLengths from equipment to control building are rounded to the nearest meter or foot and

include allowance for leads at both ends of a run

P5 Cable sizing 1

P51 Circuit breaker cables 2

Typically the same conductor sizes will be used for protection and control cables for all circuit breakers 3 The farthest circuit breaker (345CB6) is 114 m (375 ft) away from the control building The end of 4 discharge battery voltage will be 105 V The AC and DC supply conductors are often larger and may be 5 sized for each circuit breaker 6

P511 Trip coil 7

P5111 Ampacity 8





P5112 Voltage drop 18

Refer to C3 19






= 525 V 3


Rac = 525 V105 A 6

= 05 Ω 7


A = 34026 times (2 times 114 m) 05 Ω times [1 + 000393 (75 degC ndash 20 degC)] times 102 times 104 at 9

75 degC 10

= 20 017 cmil 11




= 1673 mΩm 15


= 105 A times (1673 mΩm times 114 mrun times ) 17

= 400 V or 38 18 The trip coil voltage of 101 V is above the minimum nameplate operating voltage (70 V) and should still 19 provide power for operation at the battery end-of-discharge 20

P5113 Short-circuit capability 21











A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 1

A = 3 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 2

A = 7204 cmil 3


P5114 Cable selection 5

A 6 AWG is required to satisfy the voltage drop requirements of the Trip coil This conductor size also 6 satisfies the minimum size for ampacity and for short-circuit capability A total of four conductors are 7 required so a four-conductor cable will be used 8

P512 Close coil 9

The same conductor size will be used for both the trip and close coils The conductor size of 6 AWG for the 10 105 A trip coil current will be suitable for the 105 A close coil 11

The trip circuit will require two conductors Trip coil monitoring will be used in this situation and will 12 require one additional conductor A total of three conductors are required A three-conductor cable will be 13 used 14

P513 Current transformers 15

The secondary circuit conductors for the CTs will be sized here The circuit breaker has CTs on both sides 16 of the circuit breaker that are rated 20005 A C800 for a total burden of 40 Ω The same conductor size 17 will be used for all circuit breakers The farthest circuit breaker is 114 m (375 ft) away from the control 18 building 19

P5131 Ampacity 20

The CTs have a ratio of 20005 (ratio of 400) The maximum expected secondary current will be 094 A for 21 fully rated transformer load of 225 MVA (225 MVA 345 kV radic3 400 = 3765 A 400 = 094 A) 22




P5132 Burden 30

The total burden for the CT circuit should be 40 Ω or less to maintain its accuracy This will include the 31 burden of the CT winding the circuit conductors and relay(s) 32






= 1 Ω 4




= 299 Ω 8


A = 34026 times (2 times 114 m)299 Ω times [1 + 000393 (75 degC ndash 20 degC) ] times 102 times 104 at 10 75 degC 11

= 3347 cmil 12



Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 22

= 20 A (00297 2) log 10 [(250 + 2345)(75 + 2345)] 05 23

= 372 cmil 24



The minimum conductor size for burden is 14 AWG This conductor size also satisfies the minimum size 27 for ampacity and short-circuit capability 28




P514 Spring charge motor supply 1

The circuit breaker spring charging motor is operated at 120 V (ac) and has a 16 A running current per 2 phase for a total of 48 A The power factor is 90 and 25 for run and starting respectively 3

P5141 Ampacity 4





Refer to C3 12



= 6 V 15


Rac = 6 V 48 A 17

= 0125 Ω 18




= 80 068 cmil 23




= 0525 mΩm 27






= 575 V or 48 2

NOTEmdashThe rated power factor for the spring charging motor is 25 when starting up and 90 when running continuously A 3 unity power factor has been assumed as this is the worst case scenario 4

Vmotor = 120 V ndash 575 V = 11425 V 5



Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 16

= 10 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 24 013 cmil 18



A 6 AWG conductor is required to satisfy voltage drop requirements for the circuit breaker spring charging 21 motor This conductor size also satisfies the minimum size for ampacity and for short-circuit capability A 22 3 conductor 6 AWG cable will be used with one spare 23

P515 Auxiliary ac supply 24

A single cable with three conductors will be used to supply the 120 V and 208 V loads The full load 25 current is 589 A (38 A + 1140 W208 V + 15 A receptacle + 60 W 120 V) 26




P5151 Ampacity 1


Required ampacity = (38 times 125) + ((1140 W208 V) times 125) + 15 A + (60 W120 V) = 699 A 4



The conductor will be sized for voltage drop based on an 8 A load connected to the receptacle with a 9 unity power factor and both the heater and light on This gives a current of 519 A8 A + (60 W 10 120 V) + (1140 W 208 V) + 38 A 11

Refer to C3 12



= 6 V 15


Rac = 6 V519 A 18

= 0116 Ω 19



A = 34026 times (2 times 114 m)0116 Ω times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 22 75 degC 23

= 86 280 cmil 24



Refer to C4 27










A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)]05 3

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)]05 4

= 24 013 cmil 5



A 10 AWG conductor was selected based off voltage drop This conductor size also satisfies the minimum 8 size for ampacity and for short-circuit capability 9

P516 Alarm and status 10


P52 Motor disconnect switch 15

P521 Motor supply 16

Motorized disconnect switches have a motor operator that uses 125 V (dc) has a 2 A run current and a 5 A 17 inrush current It may not be essential for the motors to be able to operate under all conditions (ie manual 18 operation may be possible even for motor operated disconnect switches) The disconnect switch motors are 19 not necessarily critical equipment and are expected to operate at the battery end of discharge voltage The 20 furthest disconnect switch is 90 m (295 ft) away from the control building 21

P5211 Ampacity 22




Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC 29 ambient temperature the smallest listed size is 14 AWG which has an ampacity of 176 A (adjusted for 30 ambient temperature) (Note that the over current protection for this conductor would be limited to 15 A 31 per Article 2404(D) of the NEC [B144]) 32





Refer to C3 2



= 58 V 5


Rac = 58 V 23 A 7

= 2522 Ω 8




= 3 133 cmil 13



Refer to C4 16



mdash Initial temperature is 75 degC 19 20




A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 25

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 7 204 cmil 27 28






A conductor size of 10 AWG will satisfy ampacity voltage drop and short-circuit capability requirements 2 for the disconnect switch motor operator 3

mdash Check starting voltage using Equation (C3) 4


= 423 mΩm 6


= 175 V 8


= 11425 V 10


P522 Status and alarms 12




A single cable with two conductors will be used to supply the 120 V ac auxiliary loads 19

P5231 Ampacity 20



Per Table 310-15 (B)(16) and Article 2404(D) of the NEC [B144] for 75 degC conductor temperature and for 23 a 40 degC ambient temperature the smallest listed size is 14 AWG which has an ampacity of 176 A 24 (adjusted for ambient temperature) (Note that the over current protection for this conductor would be 25 limited to 15 A per Article 2404(D) of the NEC [B144]) 26


Refer to C3 28






= 60 V 2


Rac = 60 V033 A 4

= 228 Ω 5



A = 34026 times (2 times 90 m)228 Ω times [1+000393(75 degC ndash 20 degC)] times 102 times 104 at 8 75 degC 9

= 347 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 20

= 7204 cmil 21





Rac = Rdc 26

= 3402610380 cmil times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 75 degC 27




= 4229 mΩm 1


= 024 V or 02 3

P53 Transformer 4

The furthest transformer from the control building is Transformer T1 totaling 87 m (285 ft) This length 5 will be used for the following example 6


The secondary conductors for the CTs will be sized here The power transformer has CTs on both the high- 8 voltage and low-voltage sides On the high-voltage side 12005 CTs are used On the low- voltage side 9 12005 CTs are used All CTs are C800 type which can have a total burden of 40 Ω 10

Conductors sized for the circuit breaker CTs will also be suitable for the power transformer CTs Per 11 P513 the minimum conductor size for ampacity burden and short-circuit capability is 14 AWG 12


Twelve (12) status and alarm points are required for the power transformers For Transformer T1 this will 14 require a total of 24 conductors The following calculations are for Transformer T1 with all copper cables 15 Two 12-conductor cables will be used providing no spare conductors for future use Since the current in 16 these conductors is small they will not be individually sized A 16 AWG conductor will be used for this 17 application The second Transformer T2 will utilize a fiber optic communications cable for its status and 18 alarm circuits Two 6-pair single mode fiber optic cables will be used for this transformer with one cable as 19 a spare 20


The power transformers have cooling fan motors with a total load of 9 kW at 208 V(ac) 95 PF The 22 control cabinet has 115 V(ac) loads consisting of a 50 W light a 20 A receptacle and 2000 W of heater at 23 208 V(ac) For voltage drop the largest load would be at maximum temperature with the fans operating 24 the light on and an 8 A load connected to the receptacle It is assumed the cabinet heater would not operate 25 when the fans are operating A three conductor cable will be used to supply the 115 V(ac) and 208 V(ac) 26 loads 27


P5331 Ampacity 30

The loads will be assumed to be continuous loads 31

Required ampacity = 9 kW208 V095 PF + (2000 W208 V) + (50 W115 V) + 8 Atimes125 = 795 A 32




Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC 1 ambient temperature 3 AWG with an ampacity of 88 A (adjusted for ambient temperature) is the smallest 2 suitable size 3



Refer to C3 6



= 104 V 9


Rdc = Rac = 104 V 539 A 12

= 0193 Ω 13


A = 34026 times (2 times 87 m) 0193 Ω times [1+000393(75 degC ndash 20 degC)] times 102 times 104 at 15 75 degC 16

= 39 575 cmil 17



Refer to C4 20






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 26

= 10 kA (00297 0033) log10 [(250 + 2345) (41 + 2345)] 05 27

= 24 013 cmil 28

The next larger commercial size remains 6 AWG (26 240 cmil) 29





A 3 AWG conductor is required for ampacity but that size is unavailable because of long lead times A 2 2 AWG conductor will be selected instead Based on this conductor size the voltage drop will be 258 3


Rac = Rdc = 3402666 360 cmil times [1+000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 5

= 0661 mΩm 6

Vdrop = 0661 mΩm times 87 mrun times radic3times 539 A 7

= 537 V or 258 8

P54 Voltage transformers 9

This section pertains to all voltage transformer types used in this example (ie VT CVT CCVT) The 10 secondary conductors for the VTs will be sized for steady-state operation The VT secondaries are wye 11 connected giving a voltage of 120 V3 or 6928 V 12

Since these VTrsquos have dual windings two 7 conductor cables will be used to supply the secondaries The 13 same conductor size will be used for all VTs The farthest VT (345CCVT1) is 82 m (269 ft) away from the 14 control building This set of VTs has a maximum allowable burden of 75 VA at 85 PF 15

P541 Ampacity 16








= 069 V 29





Rdc = Rac = 069 V 036 A 1

= 192Ω 2



A = 34026 times (2 times 82 m) 192 Ω times [1+ 000393(75 degCndash20 degC)] times 102 times 104 at 5 75 degC 6

= 3 750 cmil 7





The minimum conductor size for ampacity and voltage drop is 14 AWG Allowing ldquoIrdquo current of 01 A for 12 relay burden (electronic relays have burdens in the order of 02 VA) with power factor of 085 the 13 total burden will be 81 VA which is less than the 75 VA maximum 14


Rac = Rdc = 34026 4110 cmil times [1 + 000393 (75 degC ndash 20 degC)] times 102 times 104 at 75 degC 16

= 1068 mΩm 17

Burden of VT in VA = (Cable Resistance x (IPF) 2 + (VT Sec Voltage x (IPF) 18

Burden = (1068 mΩm times 3 x 88 m times (01 A 085 PF)2) + (693 V times 01 A 085 PF) 19

= 81 VA 20

P55 Station service supply (low side) 21

The two station service supplies have a 500 kVA capacity at 480 V and 120208 V Only one is used to 22 supply the load at a time For the purposes of this example we will only consider the 120208 V cables as 23 they will result in the larger voltage drop and larger cable The total connected load with allowance for 24 additional equipment in the future is 340 kW with an average power factor of 90 The AC panel is 25 located in the control building roughly 10 m (33 ft) from the station service transformer 26

P551 Ampacity 27

Required ampacity = (500 kVA times 125) 3 times 208 = 1735 A 28

Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient 29 temperature the smallest suitable size is 6 1c 500 kcmil per phase which has an ampacity of 3344 A each 30 for a total of 2006 A (adjusted for ambient temperature) 31




P552 Voltage drop 1


The transformer taps will be adjusted to provide a voltage of approximately 120 V at the service panel The 3 transformer has four taps of 125 each Voltage drop will be calculated for the 6 1c 500 kcmil AWG 4 conductor required for ampacity 5


Rac = Rdc = 34026 (6 times 500 000 cmil) times [1+ 000393(75 degCndash20 degC)] times 102 times 104 at 7 75 degC 8

= 0015 mΩm 9

Vdrop = 0015 mΩm times 10 mrun times 6 runs x 3times 181624 A 10

= 378 V or 182 11

Setting the transformer tap at +125 will result in a service panel voltage of approximately 20741 V 12 (208 times 10125 ndash 319 V) 13


Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 21

= 10 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 22

= 24 013 cmil 23



Six 1c 500 kcmil conductors per phase will satisfy the minimum size for ampacity and short-circuit 26 capability The transformer taps will be used to adjust the voltage to the required level 27




P56 Station service supply (high side) 1

The two station service supplies have a 500 kVA capacity at 138kV For the purposes of this section 2 calculations will be made for Station Service Transformer 1 (SST1) The station service transformer is 3 located near the control building roughly 60 m (197 ft) from the tertiary bushing of the power transformer 4

P561 Ampacity 5

Required ampacity = (500 kVA x 125) radic3 x 138kV = 261 A 6

Per Table 310-60 (C)(79) of the NEC [B144] for 90 degC conductor temperature and for a 40 degC ambient 7 temperature the smallest commercially available size is 2 AWG per phase which has an ampacity of 150 8

P562 Voltage drop 9

Load used for voltage drop calculation will be 261 A 10


Vdrop = 138kV times 003 12

= 414 V 13

mdash Per unit length resistance for cable length of 60 m (197 ft) at a temperature of 75 degC 14

Rdc = Rac = 414 V 261 A 15

= 158 Ω 16


A = 34026 times (3 times 60 m) 158 Ω times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 18 75 degC 19

= 289 cmil 20



Refer to C4 23

The cable is protected by a low side main circuit breaker with a 3-cycle maximum clearing time 24


mdash Short-time maximum conductor temperature is 250 degC per C8 26


mdash Clearing time typically three cycles (0048 s) 28





A = Isc 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 2

= 10 kA (00297 048) log10 [(250 + 2345) (75 + 2345)] 05 3

= 29410 cmil 4

The next larger commercially available size is 2 AWG (66360 cmil) 5


A 2 AWG conductor satisfies the minimum size for ampacity voltage drop and short-circuit capability 7

P57 Outdoor lighting 8

The thirty floodlights will be supplied by nineteen circuits each circuit supplying one to three floodlights 9 with two bulbs per floodlight The circuit supplying floodlights FL29 and FL30 has the longest cabling 10 distance at 159 m (499 ft) and will be used for the example Each floodlight has high power factor ballasts 11 with a 90 PF 12

Two voltage drop philosophies may be used placing the total load at the farthest point or placing the load 13 at their actual locations The first method simplifies calculations while the second method requires more 14 calculations but is more accurate The first method will be used because for a small load voltage drop will 15 likely not be the governing factor for cable sizing 16

P571 Ampacity 17


Per Table 310-15 (B)(16) of the NEC [B144] for 75 degC conductor temperature and for a 40 degC ambient 19 temperature the smallest suitable size is 14 AWG which has an ampacity of 176 A (adjusted for ambient 20 temperature) (Note that the over current protection for this conductor would be limited to 15 A per Article 21 2404(D) of the NEC [B144]) 22

P572 Voltage drop (for circuit supplying FL29 and FL30) 23




= 60 V 27


Rac = 60 V 386 A 29




= 1554 Ω 1

mdash Using Equation (C5) the distance to the furthest light FL30 is 159 m (152 m + 7 m) 2


= 8983 cmil 5

6 The next larger commercial size is 10 AWG (10 380 cmil) 7


Refer to C4 9






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 15

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 16

= 24013 cmil 17



Short-circuit capability dictates the cable size in this case and requires a 6 AWG The resulting voltage 20 drop is 171 21



= 167 mΩm 24


= 205 V or 171 (205120 times 100) 26




P58 Outdoor receptacles 1

The two outdoor 50 A receptacles will be provided The largest full load current for equipment that will be 2 used with the receptacles is 40 A at 90 PF The cables will be sized for receptacle YOUT1 and the same 3 size cable will also be used for YOUT2 4

P581 Ampacity 5







= 104 V 14


Rac = 104 V 444 A 16

= 0234 Ω 17


A = 34026 times 61 m times 2) 0234 Ω times [1 + 000393(75 degCndash20 degC)] times 102 times 104 at 19 75 degC 20

= 22 886 cmil 21



Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 2

= 10 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 3

= 24013 cmil 4



Ampacity is the governing factor for this cable and requires a 4 AWG conductor 7

P59 DC battery 8

The circuit conductors feeding the main DC panel (DCP1) from the batteries will be sized in this section 9 The batteries have a continuous load of 25 A with a 9 kA fault level A main circuit breaker is protecting 10 the DC panel from the battery system and has a maximum clearing time of 2 cycles The DC panel is 11 located approximately 5 m (16 ft) from the batteries 12

P591 Ampacity 13

The loads will be assumed to be continuous loads For ampacity 125 of continuous loads will be used 14


A 50 A protective device is used to protect the circuit Per Table 310-15 (B)(16) of the NEC [B144] for 16 75 degC conductor temperature and for a 40 degC ambient temperature the smallest suitable size is 8 AWG 17 which has an ampacity of 44 A (adjusted for ambient temperature) 18


mdash The target voltage drop is 3 from the end of discharge (EOD) voltage 20


= 315 V 22

mdash Per unit length resistance at a temperature of 75 degC 23

Rac = 315 V 25 A 24

= 0126 Ω 25


A = 34026 times 5 m times 2) 0126 Ω times [1 + 000393(75 degCndash20 degC)] times 102 times 104 at 75 degC 27

= 3484 cmil 28






Refer to C4 3






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 9

= 9 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 10

= 21612 cmil 11



Careful attention should be taken when determining the maximum voltage drop allowed from the battery 14 The minimum dc operating voltages should be evaluated for all critical equipment to determine which is 15 the least tolerant to voltage drop The most critical equipment at this station susceptible to voltage drop are 16 the circuit breaker trip and close coils 17

Circuit breaker 345CB6 is the furthest breaker at approximately 114 m (374 ft) from the control building 18 Itrsquos trip and close coils have minimum operating voltages of 70 V and 90 V respectively In this case the 19 close coil is least tolerant to voltage drop at 90 V (the trip coil can sustain an additional 20 V of drop before 20 it cuts out) 21

The calculations above show that a 6 AWG conductor satisfies the minimum size for ampacity voltage 22 drop and short-circuit capability from the battery to the DC panel Now a double check should be made to 23 verify the final voltage drop from the battery to the close coil 24

Using a 6 AWG (26240 cmil) cable from the battery to the DC panel the voltage drop to the panel is 25

Rdc = 34026 26240 cmil times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 75 degC 26

= 1673 mΩm 27

Vdrop = 25 A times 1673 mΩm times 5 m times 2 runs 28

= 0418 V 29

Voltage at the dc panel will be 30




V = 105 V ndash 0418 V 1

= 104582 V 2

Voltage at the close coil in the circuit breaker will be 3

mdash Voltage drop for 6 AWG from DC panel to the breaker (selected in section P5114) 4

Rac = Rdc = 34026 26240 cmil times [1 + 000393(75 degC ndash 20 degC)] times 102 times 104 at 75 degC 5

= 167 mΩm 6


= 147 V 8

mdash The resulting voltage delivered to the close coil will be 9

V = 10458 V ndash 147 V 10

= 10311 V 11

mdash The resulting voltage delivered to the close coil is sufficient and exceeds the minimum 12 operating voltage by 1311V 13

P510 Communication cables 14

Figure P4 is a diagram that is based upon a typical communication block diagram with some 15 modifications to show numerical identification of cable types instead of using different line types andor 16 line colors The cable types are summarized in the table below and meet the following requirements 17

1) All indoor cable meets the requirements of M1I1C1E3 18

2) All outdoor cable meets the requirements of M1I1C2E3 19

3) All communication cable is installed in a dedicated cable tray for communications cable that 20

is located near fluorescent lighting 21

22

The substation automation system architecture is a hybrid Ethernet network using direct RS232 and RS485 23 communications and via serial servers (ie terminal servers etc) Protective relay communications is also 24 required Selection of technologies and applications is based only upon providing more examples for 25 discussion Most substations will have more simplified architectures and designs including redundant 26 networks See IEEE Std C371 [B106] and IEEE Std 1615 [B104] for guidance on overall system design 27 processes as well as IEC 61850 if being implemented 28




1 2

Figure P4mdashCommunication cable diagram 3

Refer to the table below for a listing of the communication cables used in Figure P4 along with supported 4 applications and general comments 5

Table P6mdashCommunications cable applications 6

Cable ID Cable Type Location

Supported Application(s) Comments

1 Indoor-rated duplex MM FOC with the connectors selected based upon those supported by the end devices

Inter-panel installed in communications cable tray within control building

Ethernet communications

MM FOC is used not for distance issues but because the connected devices are located in different panels in application of IEEE Std 1615

2 Indoor-rated CAT 6 Ethernet cable and connectors

Intra-panel inside the control building


These devices are located within the same panel and not located near any control cables or fluorescent lighting so no shielding is required nor is fiber per application of IEEE Std 1615






3 Serial RS232 cable that provides the required RS232 signals (eg RX TX GND) and DB9M connectors

Inter-panel installed in communications cable tray within the control building

Protection communications over serial link to microwave multiplexor

Serial cable DB9M connectors should match pinouts provided from both vendors Shielded cable should be used and properly terminated using shielded connectors to ground at one end Avoid using serial cables with more wires than needed so trimming of wires in connectors is not required

4 Indoor-rated duplex SM FOC with the connectors selected based upon those supported by the end devices


Protection communications over fiber serial link

SM FOC is used because of the distance to the protection relay at the other end of the OPGW and to match the SM fiber in the OPGW

5 Outdoor-rated 144 strand SM FOC with connectors that support what is used in the patch panel

FOC between indoor patch panel and outdoor splice box

6 Outdoor-rated 144 strand SM OPGW cable

FOC between one or more outdoor splice boxes

7 Indooroutdoor-rated coaxial cable for antenna connection to satellite clock

Indooroutdoor cable between panel and external antenna mounting equipment

GPS signal from antenna

Consult vendor for distance limits of selected coaxial cable Work is ongoing in the IEEE to develop a design guide for time distribution

8 Denotes IEDs directly connected to substation equipment using control VT and CT cables routed from the substation equipment to the IEDs These are not communications cables and are not discussed in this table Refer to Clause 4 of this standard for more information

9 Indoor rated serial RS485 cable

Intra-panel inside control building

Data collection from RTU peripherals or distributed IO devices using a protocol such as IEEE Std 1815 (DNP3)

These devices are located within the same panel and not located near any control cables or fluorescent lighting but shielding is typical of RS485 cables See IEE Std C371 for discussion of RS485 cable lengths and terminations The connected devices may be located in other panels which is not a scenario covered in the small or large substation examples For this inter-panel application using RS485 use of fiber optic converters is recommended to provide isolation between panels

10 Indoor rated phone cable with RJ11 connectors on either end

Inter-panel between modems and telco isolation equipment

Remote dial-up access to HMI computer through POTS line and leased line connection to RTU for SCADA data

Leased line connections are becoming less common due to telco providers switching to frame relay or MPLS technologies In the case where the connection is not leased line this connection






collection using a protocol such as IEEE Std 1815 (DNP3)

would be implemented more like ID 13

Dial-up access to a computer is no longer a typical solution and would likely require dial-up authentication on the PC to meet security requirements such as NERC CIP Computer access typically occurs today using the computers Ethernet port using remote desktop (RDP)

11 Outdoor-rated multi-strand MM FOC with the connectors selected based upon those supported by the patch panel B one end and the patch panel C on the other

FOC between indoor patch panel and outdoor patch panel in outdoor conduit

Point to point serial RS232 communication using a proprietary protocol for SCADA data collection andor protection applications

Typically outdoor fiber optic cable can only be extended 50 feet inside a building The patch panel B in the control building needs to be located such that this requirement is met

Strand count for fiber should provide an adequate number of spare fibers Typically small strand count fiber is available but there is limited cost impact to having extra spares One method is to have all spares terminated to a patch panel so the available ports on the patch panel could dictate the number of strands to use For example if the patch panel supports 8 strands then an 8-strand fiber is used

12 Indooroutdoor-rated duplex MM FOC (patch cable) with the connectors selected based upon those supported by the device on one end and the patch panel C on the other

Fiber optic patch cable internally routed within the breaker cabinet It is not expected that this fiber would ever be routed within conduit


na

13 Indooroutdoor-rated Ethernet cable with the connectors selected based upon those supported by the devices on one either end

Inter-panel cable that also should be indooroutdoor rated

Surveillance video streaming

Refer to vendor requirements for power over Ethernet to be sure the power and distance requirements are met for the application Cable should be installed in communication cable tray and be shielded Lightning protection may be needed depending upon the location of the security camera(s) and substation lightning protection systems

14 Indoor-rated shielded Serial RS232 cable

Intra-panel serial cables do not need

Remote dial-up access to HMI

na






to be installed in cable tray or communications cable tray

computer through POTS line

Data collection from devices using a protocol such as IEEE Std 1815 (DNP3) or proprietary protocol

15 Indooroutdoor-rated duplex HCS FOC (patch cable) with the connectors selected based upon those supported by the relay on one end and the patch panel on the other

Fiber optic cable may be routed around the transformer through various conduits because the patch panel and transformer IED are not installed in the same transformer cabinet This requires a properly rated patch cord with a minimum bend radius that supports the conduit bends


See comments in ID 11

16 Indooroutdoor-rated multiple strand HCS FOC with the connectors selected based upon those supported by the patch panel on both ends







Consult vendor for coaxial cable specifications including distance limits of selected coaxial cable Work is ongoing in the IEEE to develop a design guide for timing systems

For locations without lightning protection it is recommended to provide lightning protection on this cable per vendor specification

18 Indoor rated TSP cable

Inter-panel and intra-panel but use same cable type that can be installed in communications cable tray within the control building If a separate cable tray for cables is not provided cable

IRIG-B distribution

Verify shield is properly grounded at one end on each individual cable run






should be tray rated cable to be placed in same cable tray as control cable

19 Indoor rated coaxial cable

See location in ID 18

IRIG-B distribution

Verify proper use of T-taps for coaxial cable runs and termination resistors Avoid connecting T-taps directly to relays in order to provide enough wiring clearance at the back of the relays

20 Indoor rated T1 cable Inter-panel indoor-rated T1 cable installed in communications cable tray within the control building If a separate cable tray for cables is not provided cable should be tray rated cable to be placed in same cable tray as control cable

External WAN communications

na

21 Indooroutdoor-rated coaxial cable

Indooroutdoor coaxial cable between panel and line tuner equipment

Power line carrier for protective relaying communications Consult vendor recommendations for coaxial cable type

See IEEE 643

For the SCADA components however all cables are located entirely within the control building and are 1 routed only from one component to the next All currents are on the order of a few milliamps and a very 2 small conductor size of 22 AWG or 24 AWG is sufficient Note that the physical strength of the cable 3 should be taken into account at these small sizes In this example the slightly larger 22 AWG is used for 4 longer routes while the smaller 24 AWG is used for shorter routes 5

P511 Cable summary 6

Table P7 summarizes the field cables used for each type of equipment Note that cables will not be run for 7 CT or VT windings that will not be used initially 8

Table P7mdashEquipment cable summary 9

Equipment Total number

of cables

Cables

(qty times type)

Transformer no 1 (T1) 13 2times12C14 1times3C2 10times4C14

Transformer no 2 (T2) 13 2x6PR MM Fiber 1times3C2 10times4C14

Station Service Transformer (SST1) ndash low side 21 21x500MCM (6 conductors per phase with 3





of cables

Cables

(qty times type)

neutral conductors)

Station Service Transformer (SST1) ndash high side 3 3x1C2


neutral conductors)


Battery to DC Panel (DCP1) 2 2x1C6

345kV Circuit Breaker (345CB1) 11 1x3C6 1x4C6 6x4C14 1x3C1 1x3C10 1x12C16






345kV CCVT (345CCVT1) 2 2x7C14




345kV Line 1 Fiber (FO JB5) 1 1x144PR SM Fiber


345kV Line 3 PLC Line Tuner (LT1) 1 1xCOAX


345kV Reactor (345REA1) 1 2xC14 1x2C6

138kV Capacitor Bank (138CAP1) 1 1x2C14


138kV Motor Operated Switch (138MOS1) 2 1x7C161x2C10


138kV Current Transformer (138CT1) 1 1x4C8





of cables

Cables

(qty times type)


138kV Circuit Breaker (138CB1) 9 2x6PR MM Fiber 4x4C14 1x3C1 1x3C10














138kV CCVT (138CVT1) 2 2x4C14

138kV CCVT (138CVT2) 2 2x4C14

138kV CCVT (138CVT3) 2 2x4C14

138kV CCVT (138CVT4) 2 2x4C14

138kV CCVT (138CVT5) 2 2x4C14

138kV CCVT (138CVT6) 2 2x4C14

138kV CCVT (138CVT7) 2 2x4C14

138kV CCVT (138CVT8) 2 2x4C14

138kV CCVT (138CVT9) 2 2x4C14

138kV CCVT (138CVT10) 2 2x4C14

15kV VT (15VT1) 1 1x4C14





of cables

Cables

(qty times type)

15kV VT (15VT2) 1 1x4C14

15kV Circuit Breaker (15CB1) 6 2x4C141x4C161x7C121x2C8 1x3C12


Outdoor lighting (FL1-FL40) 19 19x2C6

Outdoor receptacles (YOUT1 YOUT2) 2 2times3C4

P6 Design cable raceway 1

The raceway will consist of a combination of in-ground trenches and PVC conduit runs to individual pieces 2 of equipment See Table P8 for details 3

P61 Redundant cable requirement 4


P62 Electrical segregation 7

The voltage levels used do not require any electrical segregation However fiber circuits are segregated 8 with innerduct from the protection and control circuits Protection and control cables typically have no or 9 minimal constant current flowing in them As a result it is not customary to apply derating factors for the 10 presence of adjacent cables However the main ac station service cables will have continuous current flow 11 Adjacent cables would then need to be derated due to the mutual heating For this reason it would be 12 desirable to have separate routes for these cables 13

P63 Raceway sizing 14

The number and size of all cables going to each piece of equipment was used to prepare Table P8 The 15 cable area was based on the cables listed in Table P7 Spare capacity was not considered when sizing the 16 conduits from the equipment to the cable trench however some conduits have spare capacity The cable 17 trenches were sized using a 50 spare capacity Conduit sizes were selected based on conduit fill 18 requirements of the NEC [B144] 19

A sample calculation conduit fill calculation is given for conduit 1 from T1 to the cable trench 20

Cable area 1438 mm2



Duct diameter 338 mm (d = 23595)

Duct size selected 78 mm (3 in)





A minimum bending radius of 12 times the cable OD will be used The largest cable has a diameter of 4 2794 mm giving a minimum conduit radius of 335 mm (2794 mm times 12) PVC conduit bends are available 5 with a range of radii with 450 mm (18 in) 600 mm (24 in) and 900 mm (36 mm) being common Bends 6 with a 450 mm radius will be used for this project and satisfies the minimum bending radius 7

Table P8mdashSummary of raceway sizes 8

Raceway section Cable Area

(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

Trench to Station Service T1 17868 254 mm x 305 mm 10 inch wide x

12 inch deep

21x500MCM


12 inch deep

21x500MCM

138kV Trench North 26203 508 mm x 305mm 20 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY

138kV Trench East 1 6859 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY

138kV Trench West 1 4760 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY

Trench Main North 30200 508 mm x 305mm 20 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY

34513815kV Trench West 4433 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY

34513815kV Trench East 9060 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

138kV Cap Bank 1 Trench 2807 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY

345kV Trench South 5332 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY

Trench Main South 38239 254 mm x 305 mm 10 inch wide x

12 inch deep

NOT LISTED FOR

BREVITY

Conduit 1 to T1 1438 78 mm duct 3 inch duct 1x12C14 1x3C2

4x4C14


Conduit 3 to T2 446 53 mm duct 2 inch duct 2x6PR MM Fiber

2x4C14


Conduit 5 to 345CB1 1688 78 mm duct 3 inch duct 1x3C6 1x4C6

1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway



1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16


Conduit 17 to 345CCVT1 389 53 mm duct 2 inch duct 2x7C14




Conduit 21 to FO JB5 308 53 mm duct 2 inch duct 1x144PR SM FO



Conduit 24 to LT1 8 27 mm duct 1 inch duct 1xCOAX

Conduit 25 to 345REA1 404 53 mm duct 2 inch duct 2xC14 1x2C6

Conduit 26 to 138CAP1 100 53 mm duct 2 inch duct 1x2C14


Conduit 28 to 138MOS1 315 53 mm duct 2 inch duct 1x7C16 1x2C10


Conduit 30 to 138CT1 324 53 mm duct 2 inch duct 1x4C8


Conduit 32 to 138CB1 2099 103 mm duct 4 inch duct 2x6PR MM Fiber





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10






(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10

Conduit to 43 138CB12 2099 103 mm duct 4 inch duct 2x6PR MM Fiber

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10

Conduit 46 to 138CVT1 258 53 mm duct 2 inch duct 2x4C14










Conduit 56 to 15VT1 129 53 mm duct 2 inch duct 1x4C14






(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


1x7C12 1x2C8

1x3C12


1x7C12 1x2C8

1x3C12

Conduit 60 to FL3 304 41 mm duct 1frac12 inch duct 1x2C6

Conduit 61 FL3 to FL1 304 41 mm duct 1frac12 inch duct 1x2C6























(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway





















Conduit 100 to YOUT1 94 41 mm duct 1frac12 inch duct 1x3C4


P64 Cable installation 1

A sample calculation is shown for the ldquoConduit to T1rdquo and values for other conduits are summarized in 2 Table P9 Although this calculation is for a raceway with copper conductor cables the calculation for fiber 3 optic cables is conducted in a similar manner 4




P641 Maximum pulling tension 1

The maximum tension is calculated using Equation (J1) and Equation (J2) A general version of these 2 equations is shown in Equation (P1) to determine the minimum effective area when multiple sizes of 3 cables are pulled within the same raceway 4

Tmax = K f n A 5

= K Aeff (P1) 6

where 7

f is 10 for one or two cables and 06 for three or more cables 8 n is the number of cables per size 9 A is the total area of each size 10 Aeff is the total effective area for multiple conductors in a cable or combined cable sizes 11 12

The cables to T1 are 1times12C14 1times3C2 4x4C14 (see Table P7) Aeff for each conductor size is summarized 13 in Table P8 14

Table P9mdashAeff for different cable sizes 15


(cmil)

Total area A

(cmil) f

Aeff

(cmil)

1 12 4 110 (14 AWG) 49 320 10 49 320 1 3 66 360 (2 AWG) 199 080 10 199 080 4 4 4110 (14 AWG) 65 760 06 39 456

16

The minimum effective area (Aeff) is 39 456 cmil The maximum pulling tension (note area was changed to 17 kcmil) is determined by using Equation (P1) as follows 18


= 140463 = 14 kN (3158 lb) 20


The maximum tension for this pull is 14 kN A basket grip will be used to pull these cables which is rated 23 for a maximum of 445 kN pulling tension 24

P642 Jam ratio 25

Cable jamming may occur due to wedging of cables in the raceway There are six cables being pulled 26 for T1 refer to Table P8 for the values used in this example 27


Cable diameter = 99 mm 29




Dd = 7899 = 079 1

Since the ratio is below 25 jamming will not be a concern 2

P643 Pulling tension 3

The raceway route from the main cable trench to T1 consists of the following (see Figure P3) 4







The cables will be pulled through PVC ducts (conduits 1 and 2 from T1 see Table P8) This example will 12 focus on the cables in conduit 1 The coefficient of friction K is 05 for unlubricated duct and 02 for 13 lubricated duct Lubrication will be used so K is 02 14

P6431 Section 1 15


Tin = l x m x g 24


= 774 N 26

Equation (J15) may be used provided the incoming tension is greater than or equal 10Wr The initial 27 tension of 774 N is greater than 10Wr (2606 N in this case) so the simplified formula may be used 28

Tout = Tine fcθ 29

For this case 30

f = 02 31




c = 14 (for four cables or more) 1

θ = π2 radians 2

Tout = 774 e(02)(14)(π 2) 3

= 774 e044 4

= 120 N 5

P6432 Section 2 6



For this case 9

L = 15 m 10

m = 263 kgm 11 g = 98 ms2 12

f = 02 13 c = 14 (for four cables or more) 14


= 120 N + 108 N 16

= 228 N 17

P6433 Section 3 18


Tout = Tin e fcθ 20

For this case 21

f = 02 22


θ = π2 radians 24

Tout = 228 e(02)(14)(π 2) 25

= 228 e044 26

= 355 N 27




P6431 Section 4 1



For this case 4

L = 6 m 5

m = 263 kgm 6 g = 981 ms2 7

f = 02 8 c = 14 (for four or more) 9


= 355 N + 43 N 11

= 398 N 12

P6432 Section 5 13


Tout = Tin efcθ 15

For this case 16

f = 02 17


θ = π2 radians 19

Tout = 398 e(02)(14)(π 2) 20

= 398 e044 21

= 618 N 22

This is well below the maximum pulling tension of 445 kN If it was above the maximum pulling 23 tension options to reduce the pulling tension are to change the raceway design or reduce the 24 coefficient of friction 25

P644 Sidewall bearing pressure 26

The maximum allowable sidewall bearing pressure (SWBP) for cables 8 AWG and smaller is 4380 Nm of 27 radius (300 lbfft of radius) For more than four cables the formula becomes more complicated The 28




cables may be assumed to form a cradle form in the bend and the two bottom cables will share the load 1 equally Using Equation (J7) 2


= 132 (17 kN)(2 times 045 m) 4

= 2494 kNm 5



Results for all raceways are given in Table P9 The pulling tension is below the maximum for all runs 8 shown 9

Table P10mdashSummary of cable installation parameters 10

Raceway section Number

of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 1 to T1 6 351 482 113

Conduit 2 to T1 7 176 149 035

Conduit 3 to T2 4 031 128 030

Conduit 4 to T2 9 281 284 067

Conduit 5 to 345CB1 4 11 306 049

Conduit 6 to 345CB1 7 211 326 052

Conduit 7 to 345CB2 4 11 306 027

Conduit 8 to 345CB2 7 211 326 029

Conduit 9 to 345CB3 4 11 306 049

Conduit 10 to 345CB3 7 211 326 052

Conduit 11 to 345CB4 4 11 306 077

Conduit 12 to 345CB4 7 211 326 082

Conduit 13 to 345CB5 4 11 306 077

Conduit 14 to 345CB5 7 211 326 082





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 15 to 345CB6 4 11 306 077

Conduit 16 to 345CB6 7 211 326 082

Conduit 17 to 345CCVT1 2 205 054 046

Conduit 18 to 345CCVT2 2 205 054 046

Conduit 19 to 345CCVT3 2 205 054 080

Conduit 20 to 345CCVT4 2 205 054 080

Conduit 21 to FO JB5 1 6144 032 003

Conduit 22 to FO JB6 1 6144 032 003

Conduit 23 to FO JB7 1 6144 032 003

Conduit 24 to LT1 1 082 015 004

Conduit 25 to 345REA1 3 117 059 026

Conduit 26 to 138CAP1 1 029 011 008

Conduit 27 to 138CAP2 1 029 011 008

Conduit 28 to 138MOS1 2 064 071 026

Conduit 29 to 138MOS2 2 064 071 021

Conduit 30 to 138CT1 1 235 060 005

Conduit 31 to 138CT2 1 235 060 005

Conduit 32 to 138CB1 8 140 251 029

Conduit 33 to 138CB2 8 140 251 029

Conduit 34 to 138CB3 8 140 251 029

Conduit 35 to 138CB4 8 140 251 024

Conduit 36 to 138CB5 8 140 251 044

Conduit 37 to 138CB6 8 140 251 024

Conduit 38 to 138CB7 8 140 251 029

Conduit 39 to 138CB8 8 140 251 029





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 40 to 138CB9 8 140 251 029

Conduit 41 to 138CB10 8 140 251 024

Conduit 42 to 138CB11 8 140 251 044

Conduit 43 to 138CB12 8 140 251 024

Conduit 44 to 138CB13 8 140 251 029

Conduit 45 to 138CB14 8 140 251 029

Conduit 46 to 138CVT1 2 117 034 004

Conduit 47 to 138CVT2 2 117 034 004

Conduit 48 to 138CVT3 2 117 034 005

Conduit 49 to 138CVT4 2 117 034 004

Conduit 50 to 138CVT5 2 117 034 004

Conduit 51 to 138CVT6 2 117 034 004

Conduit 52 to 138CVT7 2 117 034 005

Conduit 53 to 138CVT8 2 117 034 004

Conduit 54 to 138CVT9 2 117 034 007

Conduit 55 to 138CVT10 2 117 034 005

Conduit 56 to 15VT1 1 056 017 003

Conduit 57 to 15VT2 1 056 017 003

Conduit 58 to 15CB1 6 037 121 014

Conduit 59 to 15CB2 6 037 121 014

Conduit 60 to FL3 1 297 028 006

Conduit 61 FL3 to FL1 1 297 028 005

Conduit 62 to FL2 1 297 028 006

Conduit 63 FL2 to FL4 1 297 028 005

Conduit 64 to FL7 1 297 028 006





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 65 FL7 to FL5 1 297 028 005

Conduit 66 to FL6 1 297 028 005

Conduit 67 FL6 to FL8 1 297 028 005

Conduit 68 to FL11 1 297 028 006

Conduit 69 FL11 to FL9 1 297 028 005

Conduit 70 to FL10 1 297 028 006

Conduit 71 FL10 to FL12 1 297 028 005

Conduit 72 to FL15 1 297 028 006

Conduit 73 FL15 to FL13 1 297 028 005

Conduit 74 to FL14 1 297 028 005

Conduit 75 FL14 to FL16 1 297 028 005

Conduit 76 to FL21 1 297 028 006

Conduit 77 FL21 to FL19 1 297 028 005

Conduit 78 FL19 to FL17 1 297 028 004

Conduit 79 to FL22 1 297 028 006

Conduit 80 FL22 to FL20 1 297 028 005

Conduit 81 FL20 to FL18 1 297 028 004

Conduit 82 to FL25 1 297 028 101

Conduit 83 FL25 to FL23 1 297 028 005

Conduit 84 to FL24 1 297 028 101

Conduit 85 FL24 to FL26 1 297 028 005

Conduit 86 to FL27 1 297 028 139

Conduit 87 FL27 to FL28 1 297 028 005

Conduit 88 FL28 to FL30 1 297 028 007

Conduit 89 FL30 to FL29 1 297 028 005





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 90 to FL31 1 297 028 010

Conduit 91 to FL33 1 297 028 006

Conduit 92 FL33 to FL32 1 297 028 005

Conduit 93 to FL34 1 297 028 004

Conduit 94 FL34 to FL36 1 297 028 004

Conduit 95 to FL37 1 297 028 006

Conduit 96 FL37 to FL35 1 297 028 005

Conduit 97 to FL39 1 297 028 008

Conduit 98 to FL40 1 297 028 006

Conduit 99 FL40 to FL38 1 297 028 005

Conduit 100 to YOUT1 1 446 15 023

Conduit 101 to YOUT2 1 446 15 023

1




Annex Q 1

(informative) 2

Bibliography 3

Bibliographical references are resources that provide additional or helpful material but do not need to be 4 understood or used to implement this standard Reference to these resources is made for informational use 5 only 6

[B1] AEIC CG5 Underground Extruded Power Cable Pulling Guide13 7

[B2] AIEE Committee Report ldquoInsulation level of relay and control circuitsrdquo AIEE Transactions pt 2 8 vol 68 pp 1255ndash1257 1949 9

[B3] ANSIICEA Publication Pndash32-382 Short Circuit Characteristics of Insulated Cables 10

[B4] ANSITIA-568-C2 Balanced Twisted-Pair Telecommunications Cabling and Components 11

[B5] ANSITIA-569-C Telecommunications Pathways and Spaces 12

[B6] ANSITIA-598-C Optical Fiber Cable Color Coding 13

[B7] ANSITIA-607-B Generic Telecommunications Bonding And Grounding (Earthing) For Customer 14 Premises 15

[B8] ANSITIA-1005-A Telecommunications Infrastructure Standard for Industrial Premises 16

[B9] ANSITIAEIA TSB-95 Additional Transmission Performance Guidelines for 4-Pair 100 Ohm 17 Category 5 Cabling 18

[B10] ANSITIAEIA 568 Commercial Building Telecommunications Cabling Standard 19

[B11] ANSITIAEIA 942 Telecommunications Infrastructure Standard for Data Centers 20

[B12] ANSITIA TSB-155-A Guidelines for the Assessment and Mitigation of Installed Category 6 21 Cabling to Support 10GBASE-T 22

[B13] ASTM E 1 19-2000a Standard Test Methods for Fire Tests of Building Construction and 23 Materials14 24

[B14] ASTM B8 Standard Specification for Concentric-Lay-Stranded Copper Conductors Hard Medium-25 Hard or Soft 26

[B15] Baumgartner E A ldquoTransient protection of pilot wire cables used for high speed tone and ac pilot 27 wire relayingrdquo presented at 20th Annual Conference for Protective Relay Engineers College Station TX 28 pp 24ndash26 Apr 1967 29

[B16] Birch F H Burrows G H and Turner H J ldquoExperience with transistorized protection in 30 BritainmdashPart II Investigations into transient overvoltages on secondary wiring at EHV switching stationsrdquo 31 paper 31-04 presented at CIGRE 1968 32

[B17] Borgvall T Holmgren B Sunden D Widstrom T and Norback K ldquoVoltages in substation 33 control cables during switching operationsrdquo paper 36-05 presented at CIGRE pp 1ndash23 Aug 24 1970 34

[B18] Buckingham R P and Gooding F H ldquoThe efficiency of nonmagnetic shields on control and 35 communication cablerdquo IEEE Transactions on Power Apparatus and Systems vol PAS-89 pp 1091ndash 1099 36 1970 37

[B19] Comsa R P and Luke Y M Yu ldquoTransient electrostatic induction by EHV transmission linesrdquo 38 IEEE Transactions on Power Apparatus and Systems vol PAS-88 pp 1783ndash1787 Dec 1969 39




[B20] Dietch Dienne and Wery ldquoProgress report of Study Committee No 4 (protection and relaying)mdash 1 Appendix II Induced interference in wiring feeding protective relaysrdquo paper 3 1-01 presented at CIGRE 2 1968 3

[B21] Dietrich R E Ramberg H C and Barber T C ldquoBPA experience with EMI measurement and 4 shielding in EHV substationsrdquo Proceedings of the American Power Conference vol 32 pp 1054ndash1061 5 Apr 1970 6

[B22] EEI Underground Systems Reference Book 1957 7

[B23] EIATIA-455-191 FOTP- 191 EC-60793-1-45 Optical Fibres - Part 1-45 Measurement Methods 8 and Test Procedures ndash Mode Field Diameter 9

[B24] EIATIA-568 Commercial Building Telecommunications Wiring Standard15 10

[B25] EIATIA-569 Commercial Building Standard for Telecommunications Pathways and Spaces 11

[B26] EIATIA-607 Commercial Building Grounding and Bonding Requirements for 12 Telecommunications 13

[B27] EPRI EL-5036 Project 2334 Power Plant Electrical Reference SeriesmdashVolume 4 Wire and Cable 14

[B28] EPRI EL-2982 Project 1359-2 Measurement and Characterization of Substation Electromagnetic 15 Transients Final Report Mar 1983 16

[B29] EPRI EL-5990-SR Proceedings Telephone Lines Entering Power Substations Aug 1988 17

[B30] EPRI EL-6271 ldquoResearch results useful to utilities nowrdquo Distribution Cable Digest vol 1 18

[B31] Fillenberg R R Cleaveland G W and Harris R E ldquoExploration of transients by switching 19 capacitorsrdquo IEEE Transactions on Power Apparatus and Systems vol PAS-90 pp 250ndash260 JanFeb 20 1971 21

[B32] ldquoFire protection and prevention practices within the electric utility industryrdquo Edison Electric 22 Institute Insurance Committee Report of the Fire Protection and Prevention Task Force Mar 1960 23

[B33] Garton H L and Stolt H K ldquoField tests and corrective measures for suppression of transients on 24 solid state devices in EHV stationsrdquo Proceedings of the American Power Conference vol 31 pp 1029ndash 25 1038 1969 26

[B34] Gavazza R J and Wiggins C M ldquoReduction of interference on substation low voltage wiringrdquo 27 IEEE Transactions on Power Delivery vol 11 no 3 pp 1317ndash1329 July 1996 28

[B35] Gillies D A and Ramberg H C ldquoMethods for reducing induced voltages in secondary circuitsrdquo 29 IEEE Transactions on Power Apparatus and Systems vol PAS-86 pp 907ndash916 July 1967 30

[B36] Gillies D A and Rogers E J ldquoInduced transient voltage reductions in Bonneville Power 31 Administration 500 kV substationrdquo presented at the IEEE PES Summer Power Meeting San Francisco 32 CA July 9ndash14 1972 paper C 72-522-1 33

[B37] Gillies D A and Rogers E J ldquoShunt capacitor switching EMI voltages their reduction in 34 Bonneville Power Administration substationsrdquo IEEE Transactions on Power Apparatus and Systems vol 35 PAS-93 pp 1849ndash1 860 NovDec 1974 36

[B38] Gillies D A Rogers E J and Ramberg H D ldquoTransient voltages-high voltage capacitor 37 switchingrdquo presented at the 20th Annual Conference for Relay Engineers College Station TX Apr 1967 38

[B39] Gooding F H and Slade H B ldquoShielding of communication cablesrdquo AIEE Transactions 39 (Communication and Electronics) vol 75 pp 378ndash387 July 1955 40

[B40] Halman T R and Harris L K ldquoVoltage surges in relay control circuitsrdquo AIEE Transactions pt 2 41 vol 67 pp 1693ndash1701 1948 42

[B41] Hammerlund B ldquoNoise and noise rejection methods in control circuits particularly for HV power 43 stationsrdquo Proceedings of the IEEE Electromagnetic Compatibility Symposium July 1968 pp 216ndash227 44




[B42] Hampe G W ldquoPower system transients with emphasis on control and propagation at radio 1 frequenciesrdquo presented at the 21st Annual Conference for Protective Relay Engineers College Station TX 2 Apr 1968 3

[B43] Harvey S M ldquoControl wiring and transients and electromagnetic compatibility in GISrdquo 4 Proceedings of the International Symposium of Gas-Insulated Substations 5

[B44] Harvey S M and Ponke W J ldquoElectromagnetic shielding of a system computer in a 230 kV 6 substationrdquo presented at the IEEE PES Summer Meeting San Francisco CA July 20ndash25 1975 paper F 75 7 442-4 8

[B45] Hicks R L and Jones D E ldquoTransient voltages on power station wiringrdquo IEEE Transactions on 9 Power Apparatus and Systems vol PAS-90 pp 26 1ndash269 JanFeb 1971 10

[B46] ICEA S-83-596 Standard for Optical Fiber Premises Distribution Cable 11

[B47] ICEA T-29-520 Vertical Cable Tray Flame Test 210000 BTU 12


[B49] IEC 60227 Parts 1ndash7 (with amendments and various editions for the parts) Polyvinyl chloride 14 insulated cables of rated voltages up to and including 450750 V16 15

[B50] IEC 60228 Conductors of Insulated Cables 16

[B51] IEC 60245 Parts 1ndash8 (with amendments and various editions for the parts) Rubber insulated 17 cablesmdashRated voltages up to and including 450750 V 18

[B52] IEC 60287 Parts 1-1 through 3-2 (with amendments and various editions for the parts) Electric 19 cablesmdashCalculation of the current rating 20

[B53] IEC 60304 Standard colours for insulation for low-frequency cables and wires 21

[B54] IEC 60332 Parts 1-1 through 3-25 (with amendments and various editions for the parts) Tests on 22 electric and optical fibre cables under fire conditions 23

[B55] IEC 60529 Degrees of Protection Provided by Enclosures (IP Code) 24

[B56] IEC 60654-4 Operating conditions for industrial-process measurement and control equipment Part 25 4 Corrosive and erosive influences 26

[B57] IEC 60694 Common specifications for high-voltage switchgear and controlgear standards 27

[B58] IEC 60793-2-10 Optical fibres - Part 2-10 Product specifications - Sectional specification for 28 category A1 multimode fibres 29

[B59] IEC 61000-4-1 Electromagnetic Compatibility (EMC)mdashPart 4-1 Testing and Measurement 30 TechniquesmdashOverview of IEC 61000-4 Series 31

[B60] IEC 61000-4-4 Electromagnetic Compatibility (EMC)mdashPart 4-4 Testing and Measurement 32 TechniquesmdashElectrical Fast TransientBurst Immunity Test 33

[B61] IEC 61000-4-5 Electromagnetic Compatibility (EMC)mdashPart 4-5 Testing and Measurement 34 TechniquesmdashSurge Immunity Test 35

[B62] IEC 61918 Industrial communication networks - Installation of communication networks in 36 industrial premises 37

[B63] IEC 61850-3 2002 Communication networks and systems in substations - Part 3 General 38 requirements 39

[B64] IEC TR 62362 Selection of optical fibre cable specifications relative to mechanical ingress 40 climatic or electromagnetic characteristics ndash Guidance 41

[B65] IEEE Committee Report ldquoA guide for the protection of wire line communications facilities serving 42 electric power stationsrdquo IEEE Transactions on Power Apparatus and Systems vol PAS-85 pp 1065ndash 43 1083 Oct 196617 18 44




[B66] IEEE Committee Report ldquoBibliography on surge voltages in ac power circuits rated 600 volts and 1 lessrdquo IEEE Transactions on Power Apparatus and Systems vol PAS-89 pp 1056ndash1061 JulyAug 1970 2

[B67] IEEE 100 The Authoritative Dictionary of IEEE Standards Terms Seventh Edition 3

[B68] IEEE Std 48 IEEE Standard Test Procedures and Requirements for AlternatingmdashCurrent Cable 4 Terminations 25 kV through 765 kV 5

[B69] IEEE Std 80 IEEE Guide for Safety in AC Substation Grounding 6

[B70] IEEE Std 81 IEEE Guide for Measuring Earth Resistivity Ground Impedance and Earth Surface 7 Potentials of a Ground SystemmdashPart 1 Normal Measurements 8

[B71] IEEE Std 82 IEEE Standard Test Procedure for Impulse Voltage Tests on Insulated Conductors 9

[B72] IEEE Std 83 TH01-4-2 Fiber Optic Applications in Electrical Substations 10

[B73] IEEE Std 367 IEEE Recommended Practice for Determining the Electric Power Station Ground 11 Potential Rise and Induced Voltage from a Power Fault 12

[B74] IEEE Std 400 IEEE Guide for Field Testing and Evaluation of the Insulation of Shielded Power 13 Cable Systems 14

[B75] IEEE Std 404 IEEE Standard for Extruded and Laminated Dielectric Shielded Cable Joints Rated 15 2500 to 500 000 V 16

[B76] IEEE Std 442 IEEE Guide for Soil Thermal Resistivity Measurements 17

[B77] IEEE Std 487 IEEE Recommended Practice for the Protection of Wire-Line Communication 18 Facilities Serving Electric Supply Locations 19

[B78] IEEE Std 4871-2014 IEEE Standard for the Electrical Protection of Communication Facilities 20 Serving Electric Supply Locations Through the Use of On-Grid Isolation Equipment 21

[B79] IEEE Std 4872 IEEE Standard for the Electrical Protection of Communication Facilities Serving 22 Electric Supply Locations through the Use of Optical Fiber Systems 23

[B80] IEEE Std 4873 IEEE Standard for the Electrical Protection of Communication Facilities Serving 24 Electric Supply Locations Through the Use of Hybrid Facilities 25

[B81] IEEE Std 4874 IEEE Standard for the Electrical Protection of Communication Facilities Serving 26 Electric Supply Locations Through the Use of Neutralizing Transformers 27

[B82] IEEE Std 4875 IEEE Standard for the Electrical Protection of Communication Facilities Serving 28 Electric Supply Locations Through the Use of Isolation Transformers 29

[B83] IEEE Std 518 IEEE Guide for the Installation of Electrical Equipment to Minimize Noise Inputs to 30 Controllers from External Sources 31

[B84] IEEE Std 532 IEEE Guide for Selecting and Testing Jackets for Underground Cables 32

[B85] IEEE Std 576 IEEE Recommended Practice for Installation Termination and Testing of Insulated 33 Power Cable as Used in Industrial and Commercial Applications 34

[B86] IEEE Std 635 IEEE Guide for Selection and Design of Aluminum Sheaths for Power Cables 35

[B87] IEEE Std 643-2004 IEEE Guide for Power-Line Carrier Applications 36

[B88] IEEE Std 789 IEEE Standard Performance Requirements for Communications and Control Cables 37 for Application in High-Voltage Environments 38

[B89] IEEE Std 8023 IEEE Standard for Ethernet 39

[B90] IEEE Std 8023an Standard for Information Technology - Telecommunications and Information 40 Exchange Between Systems ndash LANMAN - Specific Requirements Part 3 CSMACD Access Method and 41 Physical Layer Specifications - Amendment Physical Layer and Management Parameters for 10 Gbs 42 Operation Type 10GBASE-T 43




[B91] IEEE Std 848 IEEE Standard Procedure for the Determination of the Ampacity Derating of Fire-1 Protected Cables 2

[B92] IEEE Std 979 IEEE Guide for Substation Fire Protection 3

[B93] IEEE Std 1026 IEEE Recommended Practice for Test Methods for Determination of Compatibility 4 of Materials with Conductive Polymeric Insulation Shields and Jackets 5

[B94] IEEE Std 1050 IEEE Guide for Instrumentation and Control Equipment Grounding in Generating 6 Stations 7

[B95] IEEE Std 1138 IEEE Standard Construction of Composite Fiber Optic Overhead Ground Wire 8 (OPGW) for Use on Electric Utility Power Lines 9

[B96] IEEE Std 1143 IEEE Guide on Shielding Practice for Low Voltage Cables 10

[B97] IEEE Std 1202 Standard for Flame Testing of Cables for Use in Cable Tray in Industrial and 11 Commercial Occupancies 12

[B98] IEEE Std 1210 IEEE Standard Tests for Determining Compatibility of Cable-Pulling Lubricants 13 with Wire and Cable 14

[B99] IEEE Std 1222 IEEE Standard for Testing and Performance for All-Dielectric Self-Supporting 15 (ADSS) Fiber Optic Cable for Use on Electric Utility Power Lines 16

[B100] IEEE Std 1235 IEEE Guide for the Properties of Identifiable Jackets for Underground Power 17 Cables and Ducts 18

[B101] IEEE Std 1590 IEEE Recommended Practice for the Electrical Protection of Communication 19 Facilities Serving Electrical Supply Locations Using Optical Fiber Systems 20

[B102] IEEE Std 1594 IEEE Standard for Helically Applied Fiber Optic Cable Systems (Wrap Cable) for 21 Use on Overhead Utility Lines 22

[B103] IEEE Std 1613 IEEE Standard Environmental and Testing Requirements for Communications 23 Networking Devices in Electric Power Substations 24

[B104] IEEE Std 1615 IEEE Recommended Practice for Network Communication in Electric Power 25 Substations 26

[B105] IEEE Std 1815 IEEE Standard for Electric Power Systems Communications-Distributed Network 27 Protocol (DNP3) 28

[B106] IEEE Std C371 IEEE Standard for SCADA and Automatic Systems 29

[B107] IEEE Std C37901 IEEE Standard Surge Withstand Capability (SWC) Tests for Relays and 30 Relay Systems Associated with Electric Power Apparatus 31

[B108] IEEE Std C3793 IEEE Guide for Power System Protective Relay Applications of Audio Tones 32 Over Voice Grade Channels 33

[B109] IEEE Std C3799 IEEE Guide for the Protection of Shunt Capacitor Banks 34

[B110] IEEE Std C371221 IEEE Guide for Gas-Insulated Substations 35

[B111] IEEE Std C37236 IEEE Guide for Power System Protective Relay Applications Over Digital 36 Communication Channels 37

[B112] IEEE Std C5713 IEEE Standard Requirements for Instrument Transformers 38

[B113] IEEE Std C57133 IEEE Guide for the Grounding of Instrument Transformer Secondary Circuits 39 and Cases 40

[B114] IEEE P15912 Standard for Testing and Performance of Hardware for All-Dielectric Self-41 Supporting (ADSS) Fiber Optic Cable 42

[B115] ISOIEC 11801 Information technology ndash Generic cabling for customer premises 43




[B116] ISOIEC 24702-2006 Information technology ndash Generic cabling ndash Industrial Premises 1

[B117] ISOIEC TR 24750-2007 Information technology ndash Assessment and mitigation of installed 2 balanced cabling channels in order to support of 10GBASE-T 3

[B118] ITU-T G6511 Characteristics of a 50125 microm multimode graded index optical fibre cable for the 4 optical access network 5

[B119] ITU-T G652 Characteristics of a single-mode optical fibre and cable 6

[B120] ITU-T G657 Characteristics of a bending-loss insensitive single-mode optical fibre and cable for 7 the access network 8

[B121] Jaczewski M and Pilatowicz A ldquoInterference between power and telecommunication linesrdquo 9 paper 36-03 presented at CIGRE pp 1ndash8 Aug 24 1970 10

[B122] Kotheimer W C ldquoControl circuit transients in electric power systemsrdquo presented at the 21st 11 Annual Conference for Protective Engineers College Station TX Apr 22ndash24 1968 12

[B123] Kotheimer W C ldquoControl circuit transientsrdquo Power Engineering vol 73 pp 42ndash45 Jan 1969 13 and pp 54ndash56 Feb 1969 14

[B124] Kotheimer W C ldquoThe influence of station design on control circuit transientsrdquo Proceedings of 15 the American Power Conference vol 21 pp 1021ndash1028 1969 16

[B125] Kotheimer W C ldquoTheory of shielding and grounding of control cables to reduce surgesrdquo 17 Pennsylvania Electric Association Stroudsburg PA Oct 5 1973 18

[B126] Martzloff F D and Hahn G J ldquoSurge voltages in residential and industrial power circuitsrdquo 19 IEEE Transactions on Power Apparatus and Systems vol PAS-89 pp 1049ndash1056 JulyAug 1970 20

[B127] McKenna D and OrsquoSullivan T C ldquoInduced voltages in coaxial cables and telephone linesrdquo 21 paper 36-01 presented at CIGRE pp 1ndash10 Aug 24 1970 22

[B128] ldquoMethods of reducing transient overvoltages in substation control cablesrdquo British Columbia 23 Hydro and Power Authority Report No 6903 June 15 1969 24

[B129] Mildner R C Arends C B and Woodland P C ldquoThe short-circuit rating of thin metal tape 25 cable shieldsrdquo IEEE Transactions on Power Apparatus and Systems vol PAS-87 pp 749ndash759 Mar 1968 26

[B130] Neher J H and McGrath M H ldquoThe calculation of the temperature rise and load capability of 27 cable systemsrdquo AIEE Transactions vol 76 pt III pp 752ndash772 Oct 1957 28

[B131] NEMA FB 210 Selection and Installation Guidelines for Fittings for Use with Non-flexible 29 Electrical Metal Conduit or Tubing (Rigid Metal Conduit Intermediate Metal Conduit and Electrical 30 Metallic Tubing)19 31

[B132] NEMA FB 220 Selection and Installation Guidelines For Fittings for Use With Flexible 32 Electrical Conduit and Cable 33

[B133] NEMA FG 1 Fiberglass Cable Tray Systems 34

[B134] NEMA TC 3Polyvinyl Chloride (PVC) Fittings for Use with Rigid PVC Conduit and Tubing 35

[B135] NEMA TC 6amp8 Polyvinyl Chloride (PVC) Plastic Utilities for Underground Installations 36

[B136] NEMA TC 9 Fittings for Polyvinyl Chloride (PVC) Plastic Utilities Duct for Underground 37 Installation 38

[B137] NEMA VE 1 Metallic Cable Tray Systems 39

[B138] NEMA VE 2 Metal Cable Tray Installation Guidelines 40

[B139] NEMA WC 51ICEA P-54-440 3d ed Ampacities of Cables in Open-Top Cable Trays 41

[B140] NEMA WC 57ICEA S-73-532 Standard for Control Thermocouple Extension and 42 Instrumentation Cables 43




[B141] NEMA WC 70ICEA S-95-658-1999 Nonshielded Power Cables Rated 2000 Volts or Less for 1 the Distribution of Electrical Energy 2

[B142] NEMA WC 71ICEA S-96-659-1999 Standard for Nonshielded Cables Rated 2001ndash5000 Volts 3 for use in the Distribution of Electric Energy 4

[B143] NEMA WC 74ICEA S-93-639 5ndash46 kV Shielded Power Cable for the Transmission and 5 Distribution of Electric Energy 6

[B144] NFPA 70 National Electrical Code (NEC) 7

[B145] NFPA 72 National Fire Alarm Code 8

[B146] Pesonen A Kattelus J Alatalo P and Grand G ldquoEarth potential rise and telecommunication 9 linesrdquo paper 36-04 presented at CIGRE pp 1ndash21 Aug 24 1970 10

[B147] Perfecky L J and Tibensky M S ldquoMethods for RMS symmetrical station ground potential rise 11 calculations for protection of telecommunications circuits entering power stationsrdquo IEEE Transactions on 12 Power Apparatus and Systems vol PAS-1 00 no 12 pp 4785ndash4794 Dec 1981 13

[B148] ldquoProtection against transientsrdquo Silent Sentinels (Westinghouse) RPL 71-4 Aug 1971 14

[B149] Rackowski et al ldquoEffect of switching shunt capacitors on buses protected by linear coupler 15 differential relaysrdquo Westinghouse Electric Corporation Pittsburgh PA Electric Utility Engineering Report 16 No 59ndash70 17

[B150] ldquoRecommended Good Practice for the Installation of Nonmetallic Jacketed Cables in Troughs and 18 the Protection of Electrical Center Roomsrdquo Factory Insurance Association 9-69-1 5C 19

[B151] Rifenburg R C ldquoPipe-line design for pipe-type feedersrdquo AIEE Transactions (Power Apparatus 20 and Systems) vol 72 pp 1275ndash1288 Dec 1953 21

[B152] Rorden H L Dills J M Griscom S B Skooglund J W and Beck E ldquoInvestigations of 22 switching surges caused by 345 kV disconnecting switch operationrdquo AIEE Transactions (Power Apparatus 23 and Systems) vol 77 pp 838ndash844 Oct 1958 24

[B153] Sonnemann W K ldquoA laboratory study of high-voltage high-frequency transientsrdquo presented at 25 the 18th Annual Conference for Protective Relay Engineers College Station TX Apr 1965 26

[B154] Sonnemann W K ldquoTransient voltages in relay control circuitsrdquo AIEE Transactions (Power 27 Apparatus and Systems) vol 80 pp 1155ndash1162 Feb 1962 28

[B155] Sonnemann W K ldquoTransient voltages in relay control circuitsmdashPart IIrdquo presented at the 16th 29 Annual Conference for Protective Relay Engineers College Station TX Apr 1963 30

[B156] Sonnemann W K ldquoVoltage surges in relay control circuitsrdquo presented at the 13th Annual 31 Conference for Protective Relay Engineers College Station TX Apr 1960 32

[B157] Sonnemann W K and Felton R J ldquoTransient voltage measurement techniquesrdquo IEEE 33 Transactions on Power Apparatus and Systems vol PAS-87 pp 1173ndash1179 Apr 1968 34

[B158] Sonnemann W K and Marieni G I ldquoA review of transients voltages in control circuitsrdquo Silent 35 Sentinels (Westinghouse) RPL 67-3 Apr 1973 36

[B159] ldquoSubstation fire prevention and protectionrdquo Fire Protection and Prevention Task Force EE1 37 Insurance Committee Nov 1969 38

[B160] Sullivan R J ldquoTransient and solid state circuitsrdquo presented at the Pennsylvania Electric 39 Association Conference May 21 1971 40

[B161] Sutton H J ldquoTransient pickup in 500 kV control circuitsrdquo Proceedings of the American Power 41 Conference Apr 1970 42

[B162] Sutton H J ldquoTransients induced in control cables located in EHV substationrdquo IEEE 43 Transactions on Power Apparatus and Systems vol PAS-89 pp 1069ndash1081 JulyAug 1970 44




[B163] Williams K L and Lawther M A ldquoInstalling substation control cablerdquo Transmission and 1 Distribution May 1971 2

[B164] Woodland F Jr ldquoElectrical interference aspects of buried electric power and telephone linesrdquo 3 IEEE Transactions on Power Apparatus and Systems vol PAS-89 pp 275ndash280 Feb 1970 4

[B165] UL 44 Thermoset-Insulated Wires and Cables 5

[B166] UL 83 Thermoplastic-Insulated Wires and Cables 6

[B167] UL 854 Service-Entrance Cables 7

[B168] UL 1277 Standard for Electrical Power and Control Tray Cables with Optional Optical-Fiber 8 Members 9



Abstract The design installation and protection of wire and cable systems in substations are 1 covered in this guide with the objective of minimizing cable failures and their consequences 2 Keywords acceptance testing cable cable installation cable selection communication cable 3 electrical segregation fiber-optic cable handling power cable pulling tension raceway 4 recommended maintenance routing separation of redundant cable service conditions 5 substation transient protection 6

















iv

Notice to users 1



Copyrights 8




Errata 24


Patents 28





v





vi

Participants 1







31






44










66 ltNamegt 67


ltNamegt 70




vii


2




viii

Introduction 1






7




ix

Contents 1











x











xi















xii






1



Substations 3



1 Overview 15


11 Scope 23





12 Purpose 1

































41 General 18
















4311 CT circuits 29







4312 VT circuits 6

























































1) General 23








6) Cable pulling 3

7) Handling 4

8) Installation 5



51 General 8













cable 24


















d) Coaxial cables 7




























5123 USB cables 34














Distance (m)

1


No standard exists


level 1

Less than 1 MHz

2


No standard exists


4 MHz 4 Mbps

3


TIAEIA-568-C


4


20 MHz 16 Mbps

5



TIAEIA-568-A

100 MHz10 Mbps

100 Mbps 1000 Mbps



5e




100 Mhz10 Mbps

100 Mbps 1000 Mbps




TIAEIA-568-C

250 MHz

10 Mbps 100 Mbps

1000 Mbps 10GBaseT



10GBaseT


TIAEIA-568-C

500 MHz



3

































515 Terminations 28








5152 Terminals 20





















Common Name


RJ11 RJ11C RJ11W








2





























Type TCrdquo 11



c) Rated 600 V 14












b) Serial cable 5

c) Ethernet cable 6

d) Coaxial cable 7















542 Routing 22

























































a) Conduit size 33







e) Cable weight 1



h) Lubricants 4


j) Firestopping 6


57 Handling 17






















cabling systems) 23





592 USB cables 28







594 Other cables 4
















2) Fiber types 25



5) Terminations 28








10) Cable pulling 2

11) Handling 3

12) Installation 4



61 General 7






















62 Fiber types 8





G655C G655D



B13 B4C B4D


NA 850 1300

850 1300

850 1300

850 1300

1310 1550

1310 1383 1550


NA 3515 3515 3515 3515 10 04


NA 200 500 1500 3500 NA NA


NA 500 500 500 500 NA NA





NA Not specified

Not specified

2000 4700 NA NA


NA 2000 2000 2000 2000 2000 2000


NA 275 550 550 1000 2000 2000


NA 33 82 300 550 2000 2000


NA Not supported

Not supported

100 150 2000 2000


NA Not supported

Not supported

100 150 2000 2000

1


















outside substation

1
























































44





627 Ribbon cables 7



















































6211 Terminations 7





mm ST 1 Stab and


1 IEC 61754-2



Rare X 25


2 Stick and Click



1 IEC 61754-4

2 TIA-568-A



25



1 IEC 61754-18



X 245times44 mm


2 Lucent Connector

1 IEC 61754-20

2 FOCIS


X X 125




3 Local Connector

10 EIATIA-604-10



2 Fiber Channel

3 Face Contact

1 IEC 61754-13



X 25



X X Varies


X 22

1














a) Fiber type 18



d) Cable jacket 21

e) Terminations 22

641 Fiber type 23






specifications 34















Loose or tight 11





644 Cable jacket 26




















substation 22










6511 Raceway 3































6515 Splicing 4




652 Routing 15







































































71 General 14

















































































Annex A 1

(informative) 2

Flowchart 3





START


Cable Selection










Considered




Installation

Acceptance Testing


Finish






Yes

Yes

Yes

Yes

Yes


Annex B

Annex C

Annex D

Annex E

Annex F

Annex G

Annex H

Annex I

Annex J

Annex G

Annex K

Annex L

Annex M

Annex N

No

No

No

No


substations 3




Annex B 1

(normative) 2


















IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8







IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8










Crush (TSB-1852009)









Impact (ISO 24702-2006)





































IP4x















IP20 1 IP54 3 IP66 4 4X IP67 6 IP68 6P






IEC 60721-3-3 Class 3K7
















IEC 60721-3-3 Class 3K1

IEC 60721-3-3 Class 3K7

IEC 61131-2







IEC 60721-3-3 Class 3K5



































IEC 61326 IEC 61000-6-2 IEC 61326




IEC 61000-6-1 IEC 61000-2-5 IEC 61131-2







IEC 61000-6-1 IEC 61000-6-1 IEC 61000-6-2 IEC 61326















Annex C 1

(normative) 2



C1 Conductor 10


C11 Material 14












C12 Size 1




C13 Construction 9




Class Use





B 7 19 37 C 19 37 61

D 37 61 91

G 49 133 259

H 133 259 427

K 41 (14 AWG) 65 (12 AWG)

- -




C2 Ampacity 1




















C3 Voltage drop 14



LS VVV (C1) 20

where 21




where 29















Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)




18 1620 2608 795 2 14 84 0330 102 0400

4 112 97 0380 113 0445

7 98 114 0450 131 0515

12 7 157 0620 173 0680

19 7 183 0720 198 0780 16 2580 1637 499 2 18 90 0355 107 0420

4 144 104 0410 121 0475




Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)




7 126 123 0485 147 0580

12 9 169 0665 185 0730

19 9 197 0775 213 0840 14 4110 1030 314 2 25 97 0380 113 0445

4 20 112 0440 128 0505

7 175 132 0520 157 0620

12 125 183 0720 199 0780

19 125 213 0840 240 0945 12 6530 650 198 2 30 107 0420 123 0485

4 24 123 0485 147 0580

7 21 156 0615 171 0675

12 15 203 0800 230 0905

19 15 248 0975 264 1040 10 10 380 407 124 2 40 119 0470 136 0535

4 32 146 0575 163 0640

7 28 175 0690 191 0750

12 20 240 0945 257 1010 8 16 510 255 078 1 55 71 0280 104 0410

2 55 160 0630 177 0695

3 55 170 0670 185 0730

4 44 187 0735 203 0800 6 26 240 161 049 1 75 89 0350 114 0450

2 75 180 0710 197 0775

3 75 192 0755 208 0820

4 60 211 0830 237 0935 4 41 740 101 031 1 95 102 0400 127 0500

2 95 206 0810 232 0915

3 95 230 0905 245 0965

4 76 251 0990 268 1055 2 66 360 0636 0194 1 130 118 0465 150 0590

2 130 248 0975 263 1035

3 130 263 1035 279 1100

4 104 290 1140 305 1200








LSdc FFttA

R )(11

1211 Ωm (Ωft) (C4) 8

where 9





Conductor material

Parameter Metric



(size in cmil)

Copper (100 IACS)

ρ1 [t1 = 20 degC (68degF)]




α 1 000403 degC 000403 degC 0 00224degF


61211 10)(1 LSdc FFtt

A

LR (Ω) (C5) 22







61211 10)(1 LS

dc

FFttR





where 7





2

2)(

2725

12413

283

11

SdcSdcS

dc

cs

kRkRk

RY (C8) 24

2

2)(

562

4

11

SdcSdcS

dc

cs

kRkRk

RY (C9) 25

where 26









2



22

3120270)(

181)(

S

D

xpfS

DxpfY CC

cp (C10) 8

where 9



For metric units 16

2

2)(

2725

12413

283

11)(

pdcpdcp

dc

kRkRk

Rxpf (C11) 17


2

2)(

562

4

11)(

pdcpdcp

dc

kRkRk

Rxpf (C12) 19








22

2

SM

M

dc

Ssc RX

X

R

RY (C13) 9

where 10



For metric units 17

SMM D

SX

2log6173 10 (μΩm) (C14) 18


SMM D

SX

2log9252 10 (μΩft) (C15) 20

where 21








For metric units 3

dc

PP R

DSY

890896 (C16) 4


dc

PP R

DSY

1150890 (C17) 6

where 7


C313 Reactance 10


For metric units 16

)05020

log46060(2 10

Cr



)01530

log14040(2 10

Cr


where 20







A

C

B

B Right Triangle

C

AC Symmetrical Flat

C

B

C

AB

D Cradle

B


C32 Load 3















o

o

FSC KT

KT

t

KAI

1

210


where 2






01

0210

1 Tlog

KT

K

t

K

IA

F





rating ( degC)


PE PVC 150

C5 Insulation 20


















C6 Jacket 31





C61 Material 1


C62 Markings 12


C7 Attenuation 16







Annex D 1

(informative) 2


substation 4


D1 Pre-design 6


























































Annex E 1

(normative) 2










100_

_

areaRaceway






E2 Conduit 1
































































E3 Cable tray 31






E31 Tray design 3



























E41 Dropouts 2



E42 Covers 10




E43 Grounding 17




E45 Supports 28





E46 Location 1


E5 Wireways 3







































Annex F 1

(normative) 2

Routing 3





F1 Length 21


F2 Turns 25











F4 Fire impact 28






Annex G 1

(normative) 2
























G13 Lightning 14


























a) Cable routing 14



















d) Frequency 6

e) Permeability 7









































































































Annex H 1

(normative) 2


















Annex I 1

(normative) 2













I3 Separation 1











Annex J 1

(normative) 2









J2 Design limits 25




AKTcond (J1) 30

where 31







condTT 2max (J2) 9







where 23











r

TP 0 (J5) 2


r

TcP

3

)23( 0 (J6) 4


r

TP

20 (J7) 7


r

TcP

3

)23( 0 (J8) 10

where 11


16



J23 Jam ratio 25







03d

D 4


82d

D 6


0382 d

D 8








In SI units 27

T = Lmgfc (J9) 28

where 29





In English units 8

T = Lwfc (J10) 9

where 10





17



2

3

41

dD

dc (J11) 22


2

1

1

dD

dc (J12) 24


2

21

dD

dc (J13) 26




where 1











where 2




cfinout eTT (J16) 7

where 8





A

B

C D E

F G

Riser Pole

Substation Manhole


H









100_

_

areaRaceway



9847100

2

2310

2

0943

2

2

Fill 9


530100

2

8212

2

0943

2

2

Fill 13



d

DRatioJam

051_ (J18) 17

where 18


293094

)8212(051_ RatioJam 22








Tcond = (525)(381) = 20 kN (4500 lb) 8











131

0948212

0941

12

c 25


TD = (152)(8)(981)(05)(113) = 673 kN (1518 lb) 27

TE = TDecfθ 28




where 1



TE = 673 e(113)(05)(45)(001745) 5

TE = 673 e04437 6

TE = 105 kN (2366 lb) 7

TF = TE + (30)(8)(981)(05)(113) 8

TF = 105 + 133 9

TF = 118 kN (2670 lb) 10

TG = T Fecfθ 11

TG = 118e(113)(05)(45)(001745) 12

TG = 118 e04437 13

TG = 184 kN (4161 lb) 14

TH = TG + (60)(8)(981)(05)(113) 15

TH = 184 + 266 16

TH = 211 kN (4768 lb) 17


)8103)(2(

)40018)(131(P 274 kN (188 lbft) 21

P=( 113 x 18400)(2 x 3800) =274 Nmm = 2740Nm = 274 kNm 22



TG = Lmgfc 25

TG = (60)(8)(981)(05)(113) 26

TG = 266 kN (607 lb) 27

TF = TGecfθ 28




TF = 27e04437 1

TF = 42 kN (946 lb) 2

TE = TF + (30)(8)(981)(05)(113) 3

TE = 42 + 13 4

TE = 55 kN (1250 lb) 5

TD = 55ecfθ 6

TD = 55e(113)(05)(45)(001745) 7

TD = 55e04437 8

TD = 86 kN (1948 lb) 9

TC = TD + (152)(8)(981)(05)(113) 10

TC = 86 + 67 11

TC = 153 kN (3466 lb) 12

TB = 153ecfθ 13

TB = 153e(113)(05)(90)(001745) 14

TB = 153e08873 15

TB = 372 kN (8417 lb) 16





Annex K 1

(normative) 2

Handling 3



K1 Storage 9












Annex L 1

(normative) 2

Installation 3


L1 Installation 6


























Degrees Celsius

Degrees Fahrenheit














AWG or kcmil ft m


Over 750 35 10

























Annex M 1

(normative) 2



M1 Purpose 6


M2 Tests 12







Length m (ft)

R MΩ

305 (100) 16 610 (200) 8




Length m (ft)

R MΩ

914 (300) 53 122 (400) 4 152 (500) 32 183 (600) 27 213 (700) 23 244 (800) 2 274 (900) 18

305 (1000) 16

1






Annex N 1

(normative) 2




N1 General 12



N2 Inspections 24














N4 Maintenance 32












Annex O 1

(informative) 2


O1 General 4









Parameter Value




Parameter HV LV







Parameter Value

DC system











Transformer






Voltage transformer













Refer to C11 5



O32 Insulation 11

Refer to C5 12

















Refer to Annex F 20












3

4




1


Equipment

Length (See note)

m ft



3

O5 Cable sizing 4








O5111 Ampacity 1






Refer to C3 12



= 525 V 15


Rac = 525 V10 A 18

= 0525 Ω 19




75 degC 23

= 9030 cmil 24




= 39698 mΩm 28


= 429 V 30












A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 12

A = 1000 (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 13

A = 2401 cmil 14 15




O512 Close coil 20








O5131 Ampacity 1





O5132 Burden 10




= 1 Ω 16




= 099 Ω 20



= 4789 cmil 24



Refer to C4 27









A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 6

= 20 A (002972) log 10 [(250 + 2345)(75 + 2345)] 05 7

= 372 cmil 8






O5141 Ampacity 15





Refer to C3 23



= 6 V 26


Rac = 6 V 10 A 28




= 06 Ω 1




= 7901 cmil 6




= 42289 mΩm 10



= 110 V 13

Vmotor = 120 V ndash 110 V = 109 V 14



Refer to C4 17







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 25

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 3602 cmil 27 28









O5151 Ampacity 6






Refer to C3 17



= 60 V 20


Rac = 60 V103 A 23

= 0584 Ω 24




= 8118 cmil 29







= 42289 mΩm 3





Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 16

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 3602 cmil 18










O521 Motor supply 2


O5211 Ampacity 7






Refer to C3 18



= 58 V 21


Rac = 58 V 23 A 23

= 252 Ω 24




= 1637 cmil 29






Refer to C4 2







A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 10

= 10000A (002970033) log10 [(250 + 2345)(75 + 2345)] 05 11

= 2401 cmil 12






= 1068 mΩm 19


= 50 V 21


= 111 V 23









O5231 Ampacity 4





Refer to C3 11



= 60 V 14


Rac = 60 V033 A 16

= 228 Ω 17




= 181 cmil 21



Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 3

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 4

= 3602 cmil 5





Rac = Rdc 10


= 1068 mΩm 12


= 033 V or 028 14

O53 Transformer 15













O5331 Ampacity 5






Refer to C3 13



= 120 V 16


Rdc = Rac = 120 V 36 A 19

= 0332 Ω 20



= 10 049 cmil 24



Refer to C4 27









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 4

= 15 kA (002970033) log10 [(250 + 2345) (41 + 2345)] 05 5

= 3602 cmil 6






= 1673 mΩm 12


= 517 V or 225 14



O541 Ampacity 20











= 069 V 3


Rdc = Rac = 069 V 036 A 6

= 192Ω 7




= 1675 cmil 11








= 1068 mΩm 21




O551 Ampacity 27






O552 Voltage drop 4





= 08342 mΩm 11


= 31 V or 13 13



Refer to C4 17






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 23

= 15 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 24

= 3602 cmil 25










O561 Ampacity 10







= 60 V 19


Rac = 60 V 193 A 21

= 2795 Ω 22



= 2827 cmil 26



Refer to C4 30









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 6

= 15 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 7

= 3602 cmil 8






= 1068 mΩm 15


= 464 V or 386 (464120 times 100) 17



O571 Ampacity 22










= 120 V 3


Rac = 120 V 444 A 5

= 027 Ω 6



= 12 356 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 15 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 20

= 3602 cmil 21










Remote PC

Modem

4 Wire Phone Cable

EMS Master Station

Modem

4 Wire Phone Cable

Port Switch

22 AWG

Dia

l -u

p C

ircu

it

Ded

ica

ted

C

ircu

it


22 AWG

22 AWG

HUBCAT5Ethernet

HMI PCNIC

NIC

CAT5Ethernet


22 AWG


22 AWG


22 AWG


Interpose Relays

24 AWG

Interpose Relays

24 AWG


22 AWG

IED IED IED

24 AWG 24 AWG





24 AWG

22 AWG

22 AWG












Equipment

Total number

of cables

Cables (qty x type)





































where 10








(cmil) Total area A

(cmil) f

Aeff (cmil)

2 12 2 580 (16 AWG) 61 920 10 61 920 1 2 26 240 (6 AWG) 52 480 10 52 480

3 4 6 530 (12 AWG) 78 360 06 47 016

2



= 1673 = 17 kN (376 lb) 6



O642 Jam ratio 11




Dd = 7512 = 625 16













O6431 Section 1 1


Tin = m g 10


= 50 N 12


Tout = Tine fcθ 15

For this case 16

f = 02 17


θ = π2 radians 19

Tout = 50 e(02)(132)(π 2) 20

= 50 e041 21

= 757 N 22

O6432 Section 2 23



For this case 26

L = 38 m 27

m = 17 kgm 28 g = 98 ms2 29






= 757 + 1673 N 2

= 243 N 3

O6433 Section 3 4


Tout = Tin e fcθ 6

For this case 7

f = 02 8


θ = π2 radians 10

Tout = 243 e(02)(132)(π 2) 11

= 243 e041 12

= 3679 N 13

O6434 Section 4 14


Tout = Tin efcθ 16

For this case 17

f = 02 18


θ = π2 radians 20

Tout = 3679 e(02)(132)(π 2) 21

= 3679 e041 22

= 557 N 23









= 132 (17 kN)(2 times 045 m) 7

= 2494 kNm 8






Maximumpulling

tension (kN)


Pulling tension

(kN)







1




Annex P 1

(informative) 2


P1 General 4













Parameter Value







Parameter HV LV TV





Parameter Value

DC system




Fault level 3 kA



Voltage 208120 V

Load 500 kVA







Parameter Value



(dc) 105 A Total


(dc) 105 A Total



125 V(dc) 10 48 A Total


tank heaters 38 A








134 A run 120 V(dc)





CTs (2 sets) 30005 A C800 RF8

12005 A C400 RF133


Inrush 21 Ω




Parameter Value

Trip2 170 A 125 V(dc) 10

Inrush 20 Ω


Inrush 883 Ω





Transformer

CTs High 12005 C800

Low 20005 C800

Tertiary 30005 C800

Cooling fan motors

12 746 W 208 V(ac)

FLC 32 ALRC 1109 A






90 V(dc) minimum


Status points 3

Voltage transformer























Refer to C11 4













P32 Insulation 22


Refer to C5 24








Refer to Clause 7 5






























Refer to Annex F 32













3




1


Equipment

Length

(See NOTE)

(m) (ft)












345kV CCVT (345CCVT1) 82 269

345kV CCVT (345CCVT2) 52 171

345kV CCVT (345CCVT3) 81 266

345kV CCVT (345CCVT4) 75 246





345kV Reactor (345REA1) 155 509






Equipment

Length

(See NOTE)

(m) (ft)



















138kV CCVT (138CVT1) 88 289

138kV CCVT (138CVT2) 82 269

138kV CCVT (138CVT3) 76 249

138kV CCVT (138CVT4) 70 230

138kV CCVT (138CVT5) 52 171

138kV CCVT (138CVT6) 45 148




Equipment

Length

(See NOTE)

(m) (ft)

138kV CCVT (138CVT7) 40 131

138kV CCVT (138CVT8) 33 108

138kV CCVT (138CVT9) 60 197

138kV CCVT (138CVT10) 76 249

15kV VT (15VT1) 61 200

15kV VT (15VT2) 55 180






















Equipment

Length

(See NOTE)

(m) (ft)




























Equipment

Length

(See NOTE)

(m) (ft)



DC Panel Main 5 16

AC Panel Main 10 32



P5 Cable sizing 1



P511 Trip coil 7

P5111 Ampacity 8






Refer to C3 19






= 525 V 3


Rac = 525 V105 A 6

= 05 Ω 7



75 degC 10

= 20 017 cmil 11




= 1673 mΩm 15















A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 1

A = 3 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 2

A = 7204 cmil 3




P512 Close coil 9





P5131 Ampacity 20





P5132 Burden 30







= 1 Ω 4




= 299 Ω 8



= 3347 cmil 12



Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 22

= 20 A (00297 2) log 10 [(250 + 2345)(75 + 2345)] 05 23

= 372 cmil 24









P5141 Ampacity 4





Refer to C3 12



= 6 V 15


Rac = 6 V 48 A 17

= 0125 Ω 18




= 80 068 cmil 23




= 0525 mΩm 27






= 575 V or 48 2


Vmotor = 120 V ndash 575 V = 11425 V 5



Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 16

= 10 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 24 013 cmil 18









P5151 Ampacity 1






Refer to C3 12



= 6 V 15


Rac = 6 V519 A 18

= 0116 Ω 19




= 86 280 cmil 24



Refer to C4 27










A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)]05 3

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)]05 4

= 24 013 cmil 5









P5211 Ampacity 22









Refer to C3 2



= 58 V 5


Rac = 58 V 23 A 7

= 2522 Ω 8




= 3 133 cmil 13



Refer to C4 16







A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 25

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 7 204 cmil 27 28









= 423 mΩm 6


= 175 V 8


= 11425 V 10







P5231 Ampacity 20





Refer to C3 28






= 60 V 2


Rac = 60 V033 A 4

= 228 Ω 5




= 347 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 20

= 7204 cmil 21





Rac = Rdc 26





= 4229 mΩm 1


= 024 V or 02 3

P53 Transformer 4










P5331 Ampacity 30









Refer to C3 6



= 104 V 9


Rdc = Rac = 104 V 539 A 12

= 0193 Ω 13



= 39 575 cmil 17



Refer to C4 20






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 26

= 10 kA (00297 0033) log10 [(250 + 2345) (41 + 2345)] 05 27

= 24 013 cmil 28









= 0661 mΩm 6


= 537 V or 258 8




P541 Ampacity 16








= 069 V 29





Rdc = Rac = 069 V 036 A 1

= 192Ω 2




= 3 750 cmil 7








= 1068 mΩm 17



= 81 VA 20



P551 Ampacity 27






P552 Voltage drop 1





= 0015 mΩm 9


= 378 V or 182 11



Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 21

= 10 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 22

= 24 013 cmil 23









P561 Ampacity 5



P562 Voltage drop 9




= 414 V 13


Rdc = Rac = 414 V 261 A 15

= 158 Ω 16



= 289 cmil 20



Refer to C4 23










A = Isc 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 2

= 10 kA (00297 048) log10 [(250 + 2345) (75 + 2345)] 05 3

= 29410 cmil 4







P571 Ampacity 17







= 60 V 27


Rac = 60 V 386 A 29




= 1554 Ω 1



= 8983 cmil 5



Refer to C4 9






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 15

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 16

= 24013 cmil 17






= 167 mΩm 24


= 205 V or 171 (205120 times 100) 26






P581 Ampacity 5







= 104 V 14


Rac = 104 V 444 A 16

= 0234 Ω 17



= 22 886 cmil 21



Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 2

= 10 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 3

= 24013 cmil 4




P59 DC battery 8


P591 Ampacity 13







= 315 V 22


Rac = 315 V 25 A 24

= 0126 Ω 25



= 3484 cmil 28






Refer to C4 3






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 9

= 9 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 10

= 21612 cmil 11








= 1673 mΩm 27


= 0418 V 29





V = 105 V ndash 0418 V 1

= 104582 V 2




= 167 mΩm 6


= 147 V 8


V = 10458 V ndash 147 V 10

= 10311 V 11








22





1 2




























































na








na
























IRIG-B distribution










IRIG-B distribution




na




See IEEE 643






of cables

Cables

(qty times type)








of cables

Cables

(qty times type)

neutral conductors)



neutral conductors)



























of cables

Cables

(qty times type)
















138kV CCVT (138CVT1) 2 2x4C14

138kV CCVT (138CVT2) 2 2x4C14

138kV CCVT (138CVT3) 2 2x4C14

138kV CCVT (138CVT4) 2 2x4C14

138kV CCVT (138CVT5) 2 2x4C14

138kV CCVT (138CVT6) 2 2x4C14

138kV CCVT (138CVT7) 2 2x4C14

138kV CCVT (138CVT8) 2 2x4C14

138kV CCVT (138CVT9) 2 2x4C14

138kV CCVT (138CVT10) 2 2x4C14

15kV VT (15VT1) 1 1x4C14





of cables

Cables

(qty times type)

15kV VT (15VT2) 1 1x4C14














Cable area 1438 mm2












(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


12 inch deep

21x500MCM


12 inch deep

21x500MCM


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


4x4C14



2x4C14



1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway



1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16






















(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10






(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10

















(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


1x7C12 1x2C8

1x3C12


1x7C12 1x2C8

1x3C12

























(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway






























Tmax = K f n A 5

= K Aeff (P1) 6

where 7





(cmil)

Total area A

(cmil) f

Aeff

(cmil)

1 12 4 110 (14 AWG) 49 320 10 49 320 1 3 66 360 (2 AWG) 199 080 10 199 080 4 4 4110 (14 AWG) 65 760 06 39 456

16



= 140463 = 14 kN (3158 lb) 20



P642 Jam ratio 25







Dd = 7899 = 079 1











P6431 Section 1 15


Tin = l x m x g 24


= 774 N 26


Tout = Tine fcθ 29

For this case 30

f = 02 31





θ = π2 radians 2

Tout = 774 e(02)(14)(π 2) 3

= 774 e044 4

= 120 N 5

P6432 Section 2 6



For this case 9

L = 15 m 10

m = 263 kgm 11 g = 98 ms2 12



= 120 N + 108 N 16

= 228 N 17

P6433 Section 3 18



For this case 21

f = 02 22


θ = π2 radians 24

Tout = 228 e(02)(14)(π 2) 25

= 228 e044 26

= 355 N 27




P6431 Section 4 1



For this case 4

L = 6 m 5

m = 263 kgm 6 g = 981 ms2 7



= 355 N + 43 N 11

= 398 N 12

P6432 Section 5 13


Tout = Tin efcθ 15

For this case 16

f = 02 17


θ = π2 radians 19

Tout = 398 e(02)(14)(π 2) 20

= 398 e044 21

= 618 N 22









= 132 (17 kN)(2 times 045 m) 4

= 2494 kNm 5






of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 1 to T1 6 351 482 113

Conduit 2 to T1 7 176 149 035

Conduit 3 to T2 4 031 128 030

Conduit 4 to T2 9 281 284 067

Conduit 5 to 345CB1 4 11 306 049

Conduit 6 to 345CB1 7 211 326 052

Conduit 7 to 345CB2 4 11 306 027

Conduit 8 to 345CB2 7 211 326 029

Conduit 9 to 345CB3 4 11 306 049

Conduit 10 to 345CB3 7 211 326 052

Conduit 11 to 345CB4 4 11 306 077

Conduit 12 to 345CB4 7 211 326 082

Conduit 13 to 345CB5 4 11 306 077

Conduit 14 to 345CB5 7 211 326 082





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 15 to 345CB6 4 11 306 077

Conduit 16 to 345CB6 7 211 326 082

Conduit 17 to 345CCVT1 2 205 054 046

Conduit 18 to 345CCVT2 2 205 054 046

Conduit 19 to 345CCVT3 2 205 054 080

Conduit 20 to 345CCVT4 2 205 054 080

Conduit 21 to FO JB5 1 6144 032 003

Conduit 22 to FO JB6 1 6144 032 003

Conduit 23 to FO JB7 1 6144 032 003

Conduit 24 to LT1 1 082 015 004

Conduit 25 to 345REA1 3 117 059 026

Conduit 26 to 138CAP1 1 029 011 008

Conduit 27 to 138CAP2 1 029 011 008

Conduit 28 to 138MOS1 2 064 071 026

Conduit 29 to 138MOS2 2 064 071 021

Conduit 30 to 138CT1 1 235 060 005

Conduit 31 to 138CT2 1 235 060 005

Conduit 32 to 138CB1 8 140 251 029

Conduit 33 to 138CB2 8 140 251 029

Conduit 34 to 138CB3 8 140 251 029

Conduit 35 to 138CB4 8 140 251 024

Conduit 36 to 138CB5 8 140 251 044

Conduit 37 to 138CB6 8 140 251 024

Conduit 38 to 138CB7 8 140 251 029

Conduit 39 to 138CB8 8 140 251 029





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 40 to 138CB9 8 140 251 029

Conduit 41 to 138CB10 8 140 251 024

Conduit 42 to 138CB11 8 140 251 044

Conduit 43 to 138CB12 8 140 251 024

Conduit 44 to 138CB13 8 140 251 029

Conduit 45 to 138CB14 8 140 251 029

Conduit 46 to 138CVT1 2 117 034 004

Conduit 47 to 138CVT2 2 117 034 004

Conduit 48 to 138CVT3 2 117 034 005

Conduit 49 to 138CVT4 2 117 034 004

Conduit 50 to 138CVT5 2 117 034 004

Conduit 51 to 138CVT6 2 117 034 004

Conduit 52 to 138CVT7 2 117 034 005

Conduit 53 to 138CVT8 2 117 034 004

Conduit 54 to 138CVT9 2 117 034 007

Conduit 55 to 138CVT10 2 117 034 005

Conduit 56 to 15VT1 1 056 017 003

Conduit 57 to 15VT2 1 056 017 003

Conduit 58 to 15CB1 6 037 121 014

Conduit 59 to 15CB2 6 037 121 014

Conduit 60 to FL3 1 297 028 006

Conduit 61 FL3 to FL1 1 297 028 005

Conduit 62 to FL2 1 297 028 006

Conduit 63 FL2 to FL4 1 297 028 005

Conduit 64 to FL7 1 297 028 006





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 65 FL7 to FL5 1 297 028 005

Conduit 66 to FL6 1 297 028 005

Conduit 67 FL6 to FL8 1 297 028 005

Conduit 68 to FL11 1 297 028 006

Conduit 69 FL11 to FL9 1 297 028 005

Conduit 70 to FL10 1 297 028 006

Conduit 71 FL10 to FL12 1 297 028 005

Conduit 72 to FL15 1 297 028 006

Conduit 73 FL15 to FL13 1 297 028 005

Conduit 74 to FL14 1 297 028 005

Conduit 75 FL14 to FL16 1 297 028 005

Conduit 76 to FL21 1 297 028 006

Conduit 77 FL21 to FL19 1 297 028 005

Conduit 78 FL19 to FL17 1 297 028 004

Conduit 79 to FL22 1 297 028 006

Conduit 80 FL22 to FL20 1 297 028 005

Conduit 81 FL20 to FL18 1 297 028 004

Conduit 82 to FL25 1 297 028 101

Conduit 83 FL25 to FL23 1 297 028 005

Conduit 84 to FL24 1 297 028 101

Conduit 85 FL24 to FL26 1 297 028 005

Conduit 86 to FL27 1 297 028 139

Conduit 87 FL27 to FL28 1 297 028 005

Conduit 88 FL28 to FL30 1 297 028 007

Conduit 89 FL30 to FL29 1 297 028 005





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 90 to FL31 1 297 028 010

Conduit 91 to FL33 1 297 028 006

Conduit 92 FL33 to FL32 1 297 028 005

Conduit 93 to FL34 1 297 028 004

Conduit 94 FL34 to FL36 1 297 028 004

Conduit 95 to FL37 1 297 028 006

Conduit 96 FL37 to FL35 1 297 028 005

Conduit 97 to FL39 1 297 028 008

Conduit 98 to FL40 1 297 028 006

Conduit 99 FL40 to FL38 1 297 028 005

Conduit 100 to YOUT1 1 446 15 023

Conduit 101 to YOUT2 1 446 15 023

1




Annex Q 1

(informative) 2

Bibliography 3















































































































































































































iv

Notice to users 1



Copyrights 8




Errata 24


Patents 28





v





vi

Participants 1







31






44










66 ltNamegt 67


ltNamegt 70




vii


2




viii

Introduction 1






7




ix

Contents 1











x











xi















xii






1



Substations 3



1 Overview 15


11 Scope 23





12 Purpose 1

































41 General 18
















4311 CT circuits 29







4312 VT circuits 6

























































1) General 23








6) Cable pulling 3

7) Handling 4

8) Installation 5



51 General 8













cable 24


















d) Coaxial cables 7




























5123 USB cables 34














Distance (m)

1


No standard exists


level 1

Less than 1 MHz

2


No standard exists


4 MHz 4 Mbps

3


TIAEIA-568-C


4


20 MHz 16 Mbps

5



TIAEIA-568-A

100 MHz10 Mbps

100 Mbps 1000 Mbps



5e




100 Mhz10 Mbps

100 Mbps 1000 Mbps




TIAEIA-568-C

250 MHz

10 Mbps 100 Mbps

1000 Mbps 10GBaseT



10GBaseT


TIAEIA-568-C

500 MHz



3

































515 Terminations 28








5152 Terminals 20





















Common Name


RJ11 RJ11C RJ11W








2





























Type TCrdquo 11



c) Rated 600 V 14












b) Serial cable 5

c) Ethernet cable 6

d) Coaxial cable 7















542 Routing 22

























































a) Conduit size 33







e) Cable weight 1



h) Lubricants 4


j) Firestopping 6


57 Handling 17






















cabling systems) 23





592 USB cables 28







594 Other cables 4
















2) Fiber types 25



5) Terminations 28








10) Cable pulling 2

11) Handling 3

12) Installation 4



61 General 7






















62 Fiber types 8





G655C G655D



B13 B4C B4D


NA 850 1300

850 1300

850 1300

850 1300

1310 1550

1310 1383 1550


NA 3515 3515 3515 3515 10 04


NA 200 500 1500 3500 NA NA


NA 500 500 500 500 NA NA





NA Not specified

Not specified

2000 4700 NA NA


NA 2000 2000 2000 2000 2000 2000


NA 275 550 550 1000 2000 2000


NA 33 82 300 550 2000 2000


NA Not supported

Not supported

100 150 2000 2000


NA Not supported

Not supported

100 150 2000 2000

1


















outside substation

1
























































44





627 Ribbon cables 7



















































6211 Terminations 7





mm ST 1 Stab and


1 IEC 61754-2



Rare X 25


2 Stick and Click



1 IEC 61754-4

2 TIA-568-A



25



1 IEC 61754-18



X 245times44 mm


2 Lucent Connector

1 IEC 61754-20

2 FOCIS


X X 125




3 Local Connector

10 EIATIA-604-10



2 Fiber Channel

3 Face Contact

1 IEC 61754-13



X 25



X X Varies


X 22

1














a) Fiber type 18



d) Cable jacket 21

e) Terminations 22

641 Fiber type 23






specifications 34















Loose or tight 11





644 Cable jacket 26




















substation 22










6511 Raceway 3































6515 Splicing 4




652 Routing 15







































































71 General 14

















































































Annex A 1

(informative) 2

Flowchart 3





START


Cable Selection










Considered




Installation

Acceptance Testing


Finish






Yes

Yes

Yes

Yes

Yes


Annex B

Annex C

Annex D

Annex E

Annex F

Annex G

Annex H

Annex I

Annex J

Annex G

Annex K

Annex L

Annex M

Annex N

No

No

No

No


substations 3




Annex B 1

(normative) 2


















IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8







IEC 60721-3-3 Class 3M2

IEC 60721-3-3 Class 3M6

IEC 60721-3-3 Class 3M8










Crush (TSB-1852009)









Impact (ISO 24702-2006)





































IP4x















IP20 1 IP54 3 IP66 4 4X IP67 6 IP68 6P






IEC 60721-3-3 Class 3K7
















IEC 60721-3-3 Class 3K1

IEC 60721-3-3 Class 3K7

IEC 61131-2







IEC 60721-3-3 Class 3K5



































IEC 61326 IEC 61000-6-2 IEC 61326




IEC 61000-6-1 IEC 61000-2-5 IEC 61131-2







IEC 61000-6-1 IEC 61000-6-1 IEC 61000-6-2 IEC 61326















Annex C 1

(normative) 2



C1 Conductor 10


C11 Material 14












C12 Size 1




C13 Construction 9




Class Use





B 7 19 37 C 19 37 61

D 37 61 91

G 49 133 259

H 133 259 427

K 41 (14 AWG) 65 (12 AWG)

- -




C2 Ampacity 1




















C3 Voltage drop 14



LS VVV (C1) 20

where 21




where 29















Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)




18 1620 2608 795 2 14 84 0330 102 0400

4 112 97 0380 113 0445

7 98 114 0450 131 0515

12 7 157 0620 173 0680

19 7 183 0720 198 0780 16 2580 1637 499 2 18 90 0355 107 0420

4 144 104 0410 121 0475




Conductor size Rdca

(mΩm) Rdca

(Ω1000prime)

Number of

conductors

90 degC ampacity

(A)




7 126 123 0485 147 0580

12 9 169 0665 185 0730

19 9 197 0775 213 0840 14 4110 1030 314 2 25 97 0380 113 0445

4 20 112 0440 128 0505

7 175 132 0520 157 0620

12 125 183 0720 199 0780

19 125 213 0840 240 0945 12 6530 650 198 2 30 107 0420 123 0485

4 24 123 0485 147 0580

7 21 156 0615 171 0675

12 15 203 0800 230 0905

19 15 248 0975 264 1040 10 10 380 407 124 2 40 119 0470 136 0535

4 32 146 0575 163 0640

7 28 175 0690 191 0750

12 20 240 0945 257 1010 8 16 510 255 078 1 55 71 0280 104 0410

2 55 160 0630 177 0695

3 55 170 0670 185 0730

4 44 187 0735 203 0800 6 26 240 161 049 1 75 89 0350 114 0450

2 75 180 0710 197 0775

3 75 192 0755 208 0820

4 60 211 0830 237 0935 4 41 740 101 031 1 95 102 0400 127 0500

2 95 206 0810 232 0915

3 95 230 0905 245 0965

4 76 251 0990 268 1055 2 66 360 0636 0194 1 130 118 0465 150 0590

2 130 248 0975 263 1035

3 130 263 1035 279 1100

4 104 290 1140 305 1200








LSdc FFttA

R )(11

1211 Ωm (Ωft) (C4) 8

where 9





Conductor material

Parameter Metric



(size in cmil)

Copper (100 IACS)

ρ1 [t1 = 20 degC (68degF)]




α 1 000403 degC 000403 degC 0 00224degF


61211 10)(1 LSdc FFtt

A

LR (Ω) (C5) 22







61211 10)(1 LS

dc

FFttR





where 7





2

2)(

2725

12413

283

11

SdcSdcS

dc

cs

kRkRk

RY (C8) 24

2

2)(

562

4

11

SdcSdcS

dc

cs

kRkRk

RY (C9) 25

where 26









2



22

3120270)(

181)(

S

D

xpfS

DxpfY CC

cp (C10) 8

where 9



For metric units 16

2

2)(

2725

12413

283

11)(

pdcpdcp

dc

kRkRk

Rxpf (C11) 17


2

2)(

562

4

11)(

pdcpdcp

dc

kRkRk

Rxpf (C12) 19








22

2

SM

M

dc

Ssc RX

X

R

RY (C13) 9

where 10



For metric units 17

SMM D

SX

2log6173 10 (μΩm) (C14) 18


SMM D

SX

2log9252 10 (μΩft) (C15) 20

where 21








For metric units 3

dc

PP R

DSY

890896 (C16) 4


dc

PP R

DSY

1150890 (C17) 6

where 7


C313 Reactance 10


For metric units 16

)05020

log46060(2 10

Cr



)01530

log14040(2 10

Cr


where 20







A

C

B

B Right Triangle

C

AC Symmetrical Flat

C

B

C

AB

D Cradle

B


C32 Load 3















o

o

FSC KT

KT

t

KAI

1

210


where 2






01

0210

1 Tlog

KT

K

t

K

IA

F





rating ( degC)


PE PVC 150

C5 Insulation 20


















C6 Jacket 31





C61 Material 1


C62 Markings 12


C7 Attenuation 16







Annex D 1

(informative) 2


substation 4


D1 Pre-design 6


























































Annex E 1

(normative) 2










100_

_

areaRaceway






E2 Conduit 1
































































E3 Cable tray 31






E31 Tray design 3



























E41 Dropouts 2



E42 Covers 10




E43 Grounding 17




E45 Supports 28





E46 Location 1


E5 Wireways 3







































Annex F 1

(normative) 2

Routing 3





F1 Length 21


F2 Turns 25











F4 Fire impact 28






Annex G 1

(normative) 2
























G13 Lightning 14


























a) Cable routing 14



















d) Frequency 6

e) Permeability 7









































































































Annex H 1

(normative) 2


















Annex I 1

(normative) 2













I3 Separation 1











Annex J 1

(normative) 2









J2 Design limits 25




AKTcond (J1) 30

where 31







condTT 2max (J2) 9







where 23











r

TP 0 (J5) 2


r

TcP

3

)23( 0 (J6) 4


r

TP

20 (J7) 7


r

TcP

3

)23( 0 (J8) 10

where 11


16



J23 Jam ratio 25







03d

D 4


82d

D 6


0382 d

D 8








In SI units 27

T = Lmgfc (J9) 28

where 29





In English units 8

T = Lwfc (J10) 9

where 10





17



2

3

41

dD

dc (J11) 22


2

1

1

dD

dc (J12) 24


2

21

dD

dc (J13) 26




where 1











where 2




cfinout eTT (J16) 7

where 8





A

B

C D E

F G

Riser Pole

Substation Manhole


H









100_

_

areaRaceway



9847100

2

2310

2

0943

2

2

Fill 9


530100

2

8212

2

0943

2

2

Fill 13



d

DRatioJam

051_ (J18) 17

where 18


293094

)8212(051_ RatioJam 22








Tcond = (525)(381) = 20 kN (4500 lb) 8











131

0948212

0941

12

c 25


TD = (152)(8)(981)(05)(113) = 673 kN (1518 lb) 27

TE = TDecfθ 28




where 1



TE = 673 e(113)(05)(45)(001745) 5

TE = 673 e04437 6

TE = 105 kN (2366 lb) 7

TF = TE + (30)(8)(981)(05)(113) 8

TF = 105 + 133 9

TF = 118 kN (2670 lb) 10

TG = T Fecfθ 11

TG = 118e(113)(05)(45)(001745) 12

TG = 118 e04437 13

TG = 184 kN (4161 lb) 14

TH = TG + (60)(8)(981)(05)(113) 15

TH = 184 + 266 16

TH = 211 kN (4768 lb) 17


)8103)(2(

)40018)(131(P 274 kN (188 lbft) 21

P=( 113 x 18400)(2 x 3800) =274 Nmm = 2740Nm = 274 kNm 22



TG = Lmgfc 25

TG = (60)(8)(981)(05)(113) 26

TG = 266 kN (607 lb) 27

TF = TGecfθ 28




TF = 27e04437 1

TF = 42 kN (946 lb) 2

TE = TF + (30)(8)(981)(05)(113) 3

TE = 42 + 13 4

TE = 55 kN (1250 lb) 5

TD = 55ecfθ 6

TD = 55e(113)(05)(45)(001745) 7

TD = 55e04437 8

TD = 86 kN (1948 lb) 9

TC = TD + (152)(8)(981)(05)(113) 10

TC = 86 + 67 11

TC = 153 kN (3466 lb) 12

TB = 153ecfθ 13

TB = 153e(113)(05)(90)(001745) 14

TB = 153e08873 15

TB = 372 kN (8417 lb) 16





Annex K 1

(normative) 2

Handling 3



K1 Storage 9












Annex L 1

(normative) 2

Installation 3


L1 Installation 6


























Degrees Celsius

Degrees Fahrenheit














AWG or kcmil ft m


Over 750 35 10

























Annex M 1

(normative) 2



M1 Purpose 6


M2 Tests 12







Length m (ft)

R MΩ

305 (100) 16 610 (200) 8




Length m (ft)

R MΩ

914 (300) 53 122 (400) 4 152 (500) 32 183 (600) 27 213 (700) 23 244 (800) 2 274 (900) 18

305 (1000) 16

1






Annex N 1

(normative) 2




N1 General 12



N2 Inspections 24














N4 Maintenance 32












Annex O 1

(informative) 2


O1 General 4









Parameter Value




Parameter HV LV







Parameter Value

DC system











Transformer






Voltage transformer













Refer to C11 5



O32 Insulation 11

Refer to C5 12

















Refer to Annex F 20












3

4




1


Equipment

Length (See note)

m ft



3

O5 Cable sizing 4








O5111 Ampacity 1






Refer to C3 12



= 525 V 15


Rac = 525 V10 A 18

= 0525 Ω 19




75 degC 23

= 9030 cmil 24




= 39698 mΩm 28


= 429 V 30












A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 12

A = 1000 (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 13

A = 2401 cmil 14 15




O512 Close coil 20








O5131 Ampacity 1





O5132 Burden 10




= 1 Ω 16




= 099 Ω 20



= 4789 cmil 24



Refer to C4 27









A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 6

= 20 A (002972) log 10 [(250 + 2345)(75 + 2345)] 05 7

= 372 cmil 8






O5141 Ampacity 15





Refer to C3 23



= 6 V 26


Rac = 6 V 10 A 28




= 06 Ω 1




= 7901 cmil 6




= 42289 mΩm 10



= 110 V 13

Vmotor = 120 V ndash 110 V = 109 V 14



Refer to C4 17







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 25

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 3602 cmil 27 28









O5151 Ampacity 6






Refer to C3 17



= 60 V 20


Rac = 60 V103 A 23

= 0584 Ω 24




= 8118 cmil 29







= 42289 mΩm 3





Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 16

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 3602 cmil 18










O521 Motor supply 2


O5211 Ampacity 7






Refer to C3 18



= 58 V 21


Rac = 58 V 23 A 23

= 252 Ω 24




= 1637 cmil 29






Refer to C4 2







A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 10

= 10000A (002970033) log10 [(250 + 2345)(75 + 2345)] 05 11

= 2401 cmil 12






= 1068 mΩm 19


= 50 V 21


= 111 V 23









O5231 Ampacity 4





Refer to C3 11



= 60 V 14


Rac = 60 V033 A 16

= 228 Ω 17




= 181 cmil 21



Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 3

= 15 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 4

= 3602 cmil 5





Rac = Rdc 10


= 1068 mΩm 12


= 033 V or 028 14

O53 Transformer 15













O5331 Ampacity 5






Refer to C3 13



= 120 V 16


Rdc = Rac = 120 V 36 A 19

= 0332 Ω 20



= 10 049 cmil 24



Refer to C4 27









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 4

= 15 kA (002970033) log10 [(250 + 2345) (41 + 2345)] 05 5

= 3602 cmil 6






= 1673 mΩm 12


= 517 V or 225 14



O541 Ampacity 20











= 069 V 3


Rdc = Rac = 069 V 036 A 6

= 192Ω 7




= 1675 cmil 11








= 1068 mΩm 21




O551 Ampacity 27






O552 Voltage drop 4





= 08342 mΩm 11


= 31 V or 13 13



Refer to C4 17






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 23

= 15 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 24

= 3602 cmil 25










O561 Ampacity 10







= 60 V 19


Rac = 60 V 193 A 21

= 2795 Ω 22



= 2827 cmil 26



Refer to C4 30









A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 6

= 15 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 7

= 3602 cmil 8






= 1068 mΩm 15


= 464 V or 386 (464120 times 100) 17



O571 Ampacity 22










= 120 V 3


Rac = 120 V 444 A 5

= 027 Ω 6



= 12 356 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 15 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 20

= 3602 cmil 21










Remote PC

Modem

4 Wire Phone Cable

EMS Master Station

Modem

4 Wire Phone Cable

Port Switch

22 AWG

Dia

l -u

p C

ircu

it

Ded

ica

ted

C

ircu

it


22 AWG

22 AWG

HUBCAT5Ethernet

HMI PCNIC

NIC

CAT5Ethernet


22 AWG


22 AWG


22 AWG


Interpose Relays

24 AWG

Interpose Relays

24 AWG


22 AWG

IED IED IED

24 AWG 24 AWG





24 AWG

22 AWG

22 AWG












Equipment

Total number

of cables

Cables (qty x type)





































where 10








(cmil) Total area A

(cmil) f

Aeff (cmil)

2 12 2 580 (16 AWG) 61 920 10 61 920 1 2 26 240 (6 AWG) 52 480 10 52 480

3 4 6 530 (12 AWG) 78 360 06 47 016

2



= 1673 = 17 kN (376 lb) 6



O642 Jam ratio 11




Dd = 7512 = 625 16













O6431 Section 1 1


Tin = m g 10


= 50 N 12


Tout = Tine fcθ 15

For this case 16

f = 02 17


θ = π2 radians 19

Tout = 50 e(02)(132)(π 2) 20

= 50 e041 21

= 757 N 22

O6432 Section 2 23



For this case 26

L = 38 m 27

m = 17 kgm 28 g = 98 ms2 29






= 757 + 1673 N 2

= 243 N 3

O6433 Section 3 4


Tout = Tin e fcθ 6

For this case 7

f = 02 8


θ = π2 radians 10

Tout = 243 e(02)(132)(π 2) 11

= 243 e041 12

= 3679 N 13

O6434 Section 4 14


Tout = Tin efcθ 16

For this case 17

f = 02 18


θ = π2 radians 20

Tout = 3679 e(02)(132)(π 2) 21

= 3679 e041 22

= 557 N 23









= 132 (17 kN)(2 times 045 m) 7

= 2494 kNm 8






Maximumpulling

tension (kN)


Pulling tension

(kN)







1




Annex P 1

(informative) 2


P1 General 4













Parameter Value







Parameter HV LV TV





Parameter Value

DC system




Fault level 3 kA



Voltage 208120 V

Load 500 kVA







Parameter Value



(dc) 105 A Total


(dc) 105 A Total



125 V(dc) 10 48 A Total


tank heaters 38 A








134 A run 120 V(dc)





CTs (2 sets) 30005 A C800 RF8

12005 A C400 RF133


Inrush 21 Ω




Parameter Value

Trip2 170 A 125 V(dc) 10

Inrush 20 Ω


Inrush 883 Ω





Transformer

CTs High 12005 C800

Low 20005 C800

Tertiary 30005 C800

Cooling fan motors

12 746 W 208 V(ac)

FLC 32 ALRC 1109 A






90 V(dc) minimum


Status points 3

Voltage transformer























Refer to C11 4













P32 Insulation 22


Refer to C5 24








Refer to Clause 7 5






























Refer to Annex F 32













3




1


Equipment

Length

(See NOTE)

(m) (ft)












345kV CCVT (345CCVT1) 82 269

345kV CCVT (345CCVT2) 52 171

345kV CCVT (345CCVT3) 81 266

345kV CCVT (345CCVT4) 75 246





345kV Reactor (345REA1) 155 509






Equipment

Length

(See NOTE)

(m) (ft)



















138kV CCVT (138CVT1) 88 289

138kV CCVT (138CVT2) 82 269

138kV CCVT (138CVT3) 76 249

138kV CCVT (138CVT4) 70 230

138kV CCVT (138CVT5) 52 171

138kV CCVT (138CVT6) 45 148




Equipment

Length

(See NOTE)

(m) (ft)

138kV CCVT (138CVT7) 40 131

138kV CCVT (138CVT8) 33 108

138kV CCVT (138CVT9) 60 197

138kV CCVT (138CVT10) 76 249

15kV VT (15VT1) 61 200

15kV VT (15VT2) 55 180






















Equipment

Length

(See NOTE)

(m) (ft)




























Equipment

Length

(See NOTE)

(m) (ft)



DC Panel Main 5 16

AC Panel Main 10 32



P5 Cable sizing 1



P511 Trip coil 7

P5111 Ampacity 8






Refer to C3 19






= 525 V 3


Rac = 525 V105 A 6

= 05 Ω 7



75 degC 10

= 20 017 cmil 11




= 1673 mΩm 15















A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)]05 1

A = 3 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)]05 2

A = 7204 cmil 3




P512 Close coil 9





P5131 Ampacity 20





P5132 Burden 30







= 1 Ω 4




= 299 Ω 8



= 3347 cmil 12



Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0(T1 + K0)] 05 22

= 20 A (00297 2) log 10 [(250 + 2345)(75 + 2345)] 05 23

= 372 cmil 24









P5141 Ampacity 4





Refer to C3 12



= 6 V 15


Rac = 6 V 48 A 17

= 0125 Ω 18




= 80 068 cmil 23




= 0525 mΩm 27






= 575 V or 48 2


Vmotor = 120 V ndash 575 V = 11425 V 5



Refer to C4 8







A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 16

= 10 kA (002970033) log10 [(250 + 2345)(75 + 2345)] 05 17

= 24 013 cmil 18









P5151 Ampacity 1






Refer to C3 12



= 6 V 15


Rac = 6 V519 A 18

= 0116 Ω 19




= 86 280 cmil 24



Refer to C4 27










A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)]05 3

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)]05 4

= 24 013 cmil 5









P5211 Ampacity 22









Refer to C3 2



= 58 V 5


Rac = 58 V 23 A 7

= 2522 Ω 8




= 3 133 cmil 13



Refer to C4 16







A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 25

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 26

= 7 204 cmil 27 28









= 423 mΩm 6


= 175 V 8


= 11425 V 10







P5231 Ampacity 20





Refer to C3 28






= 60 V 2


Rac = 60 V033 A 4

= 228 Ω 5




= 347 cmil 10



Refer to C4 13






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 19

= 3 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 20

= 7204 cmil 21





Rac = Rdc 26





= 4229 mΩm 1


= 024 V or 02 3

P53 Transformer 4










P5331 Ampacity 30









Refer to C3 6



= 104 V 9


Rdc = Rac = 104 V 539 A 12

= 0193 Ω 13



= 39 575 cmil 17



Refer to C4 20






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 26

= 10 kA (00297 0033) log10 [(250 + 2345) (41 + 2345)] 05 27

= 24 013 cmil 28









= 0661 mΩm 6


= 537 V or 258 8




P541 Ampacity 16








= 069 V 29





Rdc = Rac = 069 V 036 A 1

= 192Ω 2




= 3 750 cmil 7








= 1068 mΩm 17



= 81 VA 20



P551 Ampacity 27






P552 Voltage drop 1





= 0015 mΩm 9


= 378 V or 182 11



Refer to C4 15






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 21

= 10 kA (00297 0033) log10 [(250 + 2345)(41 + 2345)] 05 22

= 24 013 cmil 23









P561 Ampacity 5



P562 Voltage drop 9




= 414 V 13


Rdc = Rac = 414 V 261 A 15

= 158 Ω 16



= 289 cmil 20



Refer to C4 23










A = Isc 00297 tF log10 [ (T2 + K0)(T1 + K0) ] 05 2

= 10 kA (00297 048) log10 [(250 + 2345) (75 + 2345)] 05 3

= 29410 cmil 4







P571 Ampacity 17







= 60 V 27


Rac = 60 V 386 A 29




= 1554 Ω 1



= 8983 cmil 5



Refer to C4 9






A = ISC 00297 tF log10 [ (T2 + K0)(T1 + K0)] 05 15

= 10 kA (00297 0033) log10 [(250 + 2345)(75 + 2345)] 05 16

= 24013 cmil 17






= 167 mΩm 24


= 205 V or 171 (205120 times 100) 26






P581 Ampacity 5







= 104 V 14


Rac = 104 V 444 A 16

= 0234 Ω 17



= 22 886 cmil 21



Refer to C4 24









A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 2

= 10 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 3

= 24013 cmil 4




P59 DC battery 8


P591 Ampacity 13







= 315 V 22


Rac = 315 V 25 A 24

= 0126 Ω 25



= 3484 cmil 28






Refer to C4 3






A = ISC 00297 tF log10 [(T2 + K0)(T1 + K0)] 05 9

= 9 kA (00297 0033) log10 [(250 + 2345) (75 + 2345)] 05 10

= 21612 cmil 11








= 1673 mΩm 27


= 0418 V 29





V = 105 V ndash 0418 V 1

= 104582 V 2




= 167 mΩm 6


= 147 V 8


V = 10458 V ndash 147 V 10

= 10311 V 11








22





1 2




























































na








na
























IRIG-B distribution










IRIG-B distribution




na




See IEEE 643






of cables

Cables

(qty times type)








of cables

Cables

(qty times type)

neutral conductors)



neutral conductors)



























of cables

Cables

(qty times type)
















138kV CCVT (138CVT1) 2 2x4C14

138kV CCVT (138CVT2) 2 2x4C14

138kV CCVT (138CVT3) 2 2x4C14

138kV CCVT (138CVT4) 2 2x4C14

138kV CCVT (138CVT5) 2 2x4C14

138kV CCVT (138CVT6) 2 2x4C14

138kV CCVT (138CVT7) 2 2x4C14

138kV CCVT (138CVT8) 2 2x4C14

138kV CCVT (138CVT9) 2 2x4C14

138kV CCVT (138CVT10) 2 2x4C14

15kV VT (15VT1) 1 1x4C14





of cables

Cables

(qty times type)

15kV VT (15VT2) 1 1x4C14














Cable area 1438 mm2












(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


12 inch deep

21x500MCM


12 inch deep

21x500MCM


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


12 inch deep

NOT LISTED FOR

BREVITY


4x4C14



2x4C14



1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16





(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway



1x3C1 1x12C16



1x3C1 1x12C16



1x3C1 1x12C16






















(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10






(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway

4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10


4x4C14 1x3C1

1x3C10

















(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway


1x7C12 1x2C8

1x3C12


1x7C12 1x2C8

1x3C12

























(mm2)

Selected raceway

size (metric)

Selected raceway

size (imperial)

Cables routed in

selected raceway






























Tmax = K f n A 5

= K Aeff (P1) 6

where 7





(cmil)

Total area A

(cmil) f

Aeff

(cmil)

1 12 4 110 (14 AWG) 49 320 10 49 320 1 3 66 360 (2 AWG) 199 080 10 199 080 4 4 4110 (14 AWG) 65 760 06 39 456

16



= 140463 = 14 kN (3158 lb) 20



P642 Jam ratio 25







Dd = 7899 = 079 1











P6431 Section 1 15


Tin = l x m x g 24


= 774 N 26


Tout = Tine fcθ 29

For this case 30

f = 02 31





θ = π2 radians 2

Tout = 774 e(02)(14)(π 2) 3

= 774 e044 4

= 120 N 5

P6432 Section 2 6



For this case 9

L = 15 m 10

m = 263 kgm 11 g = 98 ms2 12



= 120 N + 108 N 16

= 228 N 17

P6433 Section 3 18



For this case 21

f = 02 22


θ = π2 radians 24

Tout = 228 e(02)(14)(π 2) 25

= 228 e044 26

= 355 N 27




P6431 Section 4 1



For this case 4

L = 6 m 5

m = 263 kgm 6 g = 981 ms2 7



= 355 N + 43 N 11

= 398 N 12

P6432 Section 5 13


Tout = Tin efcθ 15

For this case 16

f = 02 17


θ = π2 radians 19

Tout = 398 e(02)(14)(π 2) 20

= 398 e044 21

= 618 N 22









= 132 (17 kN)(2 times 045 m) 4

= 2494 kNm 5






of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 1 to T1 6 351 482 113

Conduit 2 to T1 7 176 149 035

Conduit 3 to T2 4 031 128 030

Conduit 4 to T2 9 281 284 067

Conduit 5 to 345CB1 4 11 306 049

Conduit 6 to 345CB1 7 211 326 052

Conduit 7 to 345CB2 4 11 306 027

Conduit 8 to 345CB2 7 211 326 029

Conduit 9 to 345CB3 4 11 306 049

Conduit 10 to 345CB3 7 211 326 052

Conduit 11 to 345CB4 4 11 306 077

Conduit 12 to 345CB4 7 211 326 082

Conduit 13 to 345CB5 4 11 306 077

Conduit 14 to 345CB5 7 211 326 082





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 15 to 345CB6 4 11 306 077

Conduit 16 to 345CB6 7 211 326 082

Conduit 17 to 345CCVT1 2 205 054 046

Conduit 18 to 345CCVT2 2 205 054 046

Conduit 19 to 345CCVT3 2 205 054 080

Conduit 20 to 345CCVT4 2 205 054 080

Conduit 21 to FO JB5 1 6144 032 003

Conduit 22 to FO JB6 1 6144 032 003

Conduit 23 to FO JB7 1 6144 032 003

Conduit 24 to LT1 1 082 015 004

Conduit 25 to 345REA1 3 117 059 026

Conduit 26 to 138CAP1 1 029 011 008

Conduit 27 to 138CAP2 1 029 011 008

Conduit 28 to 138MOS1 2 064 071 026

Conduit 29 to 138MOS2 2 064 071 021

Conduit 30 to 138CT1 1 235 060 005

Conduit 31 to 138CT2 1 235 060 005

Conduit 32 to 138CB1 8 140 251 029

Conduit 33 to 138CB2 8 140 251 029

Conduit 34 to 138CB3 8 140 251 029

Conduit 35 to 138CB4 8 140 251 024

Conduit 36 to 138CB5 8 140 251 044

Conduit 37 to 138CB6 8 140 251 024

Conduit 38 to 138CB7 8 140 251 029

Conduit 39 to 138CB8 8 140 251 029





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 40 to 138CB9 8 140 251 029

Conduit 41 to 138CB10 8 140 251 024

Conduit 42 to 138CB11 8 140 251 044

Conduit 43 to 138CB12 8 140 251 024

Conduit 44 to 138CB13 8 140 251 029

Conduit 45 to 138CB14 8 140 251 029

Conduit 46 to 138CVT1 2 117 034 004

Conduit 47 to 138CVT2 2 117 034 004

Conduit 48 to 138CVT3 2 117 034 005

Conduit 49 to 138CVT4 2 117 034 004

Conduit 50 to 138CVT5 2 117 034 004

Conduit 51 to 138CVT6 2 117 034 004

Conduit 52 to 138CVT7 2 117 034 005

Conduit 53 to 138CVT8 2 117 034 004

Conduit 54 to 138CVT9 2 117 034 007

Conduit 55 to 138CVT10 2 117 034 005

Conduit 56 to 15VT1 1 056 017 003

Conduit 57 to 15VT2 1 056 017 003

Conduit 58 to 15CB1 6 037 121 014

Conduit 59 to 15CB2 6 037 121 014

Conduit 60 to FL3 1 297 028 006

Conduit 61 FL3 to FL1 1 297 028 005

Conduit 62 to FL2 1 297 028 006

Conduit 63 FL2 to FL4 1 297 028 005

Conduit 64 to FL7 1 297 028 006





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 65 FL7 to FL5 1 297 028 005

Conduit 66 to FL6 1 297 028 005

Conduit 67 FL6 to FL8 1 297 028 005

Conduit 68 to FL11 1 297 028 006

Conduit 69 FL11 to FL9 1 297 028 005

Conduit 70 to FL10 1 297 028 006

Conduit 71 FL10 to FL12 1 297 028 005

Conduit 72 to FL15 1 297 028 006

Conduit 73 FL15 to FL13 1 297 028 005

Conduit 74 to FL14 1 297 028 005

Conduit 75 FL14 to FL16 1 297 028 005

Conduit 76 to FL21 1 297 028 006

Conduit 77 FL21 to FL19 1 297 028 005

Conduit 78 FL19 to FL17 1 297 028 004

Conduit 79 to FL22 1 297 028 006

Conduit 80 FL22 to FL20 1 297 028 005

Conduit 81 FL20 to FL18 1 297 028 004

Conduit 82 to FL25 1 297 028 101

Conduit 83 FL25 to FL23 1 297 028 005

Conduit 84 to FL24 1 297 028 101

Conduit 85 FL24 to FL26 1 297 028 005

Conduit 86 to FL27 1 297 028 139

Conduit 87 FL27 to FL28 1 297 028 005

Conduit 88 FL28 to FL30 1 297 028 007

Conduit 89 FL30 to FL29 1 297 028 005





of cables

Maximum

pulling

tension (kN)

Total cable

mass (kgm)

Pulling

tension

(kN)

Conduit 90 to FL31 1 297 028 010

Conduit 91 to FL33 1 297 028 006

Conduit 92 FL33 to FL32 1 297 028 005

Conduit 93 to FL34 1 297 028 004

Conduit 94 FL34 to FL36 1 297 028 004

Conduit 95 to FL37 1 297 028 006

Conduit 96 FL37 to FL35 1 297 028 005

Conduit 97 to FL39 1 297 028 008

Conduit 98 to FL40 1 297 028 006

Conduit 99 FL40 to FL38 1 297 028 005

Conduit 100 to YOUT1 1 446 15 023

Conduit 101 to YOUT2 1 446 15 023

1




Annex Q 1

(informative) 2

Bibliography 3





























































































































































































