assumption university thailand ee4503 electrical systems design cable 1

Assumption University Thailand

EE4503Electrical Systems Design

Cable

1

Assumption University Thailand

Topics

• Introduction to Cables

• Cables for low voltage

• Cables for high voltage

• Cable selection

2

Assumption University Thailand

Cables

• Functionality

– Conduct electrical power from one point to other

• Components

– Conductor

– Insulator (optional)

3

Assumption University Thailand

Cables - Conductor

• Physical

– Solid

– Strand: flexible, reduce skin effect

• Material

– Copper

– Aluminum

4

Assumption University Thailand

Cables - Conductor

http://www.cedengineering.com/upload/Electrical%20Conductors.pdf http://www.geindustrial.com/Newsletter/Aluminum_vs_Copper.pdf

5

Assumption University Thailand

Cables - Insulator

• Prevent the physical contact: between two

cables, cable-to-ground

– Physical durable e.g. impact, heat

– Chemical durable, e.g. erosion

• Commonly used

– Polyvinyl Chloride (PVC)

– Cross linked Polyethylene (XLPE)6

Assumption University Thailand

Cables - Insulator

http://www.gridcables.com/power-cable.html

7

Assumption University Thailand

Cables for High Voltage

• Withstand the high voltage: insulator (if any)

need to be good.

• Long distance transmission: Cable cost &

Installation cost (e.g. electricity pole)

• Two main types

– Bare Wires (reduce cost)

– Insulated Wires8

Assumption University Thailand

High Voltage CablesBare Wires

• Made of Aluminum for lower cost

• Transmission system (not distribution system

for safety): Reduce usage: animals, accident, etc.

• AAC: All Aluminum Cable

• AAAC: All Aluminum Alloy Cable

• ACSR: Aluminum Conductor Steel Reinforced9

Assumption University Thailand

High Voltage CablesBare Wires

• AAC: Basic type, for shorter span

• AAAC: Improve the property of Aluminum by making it as an alloy stronger, larger span, corrosion resistance (e.g. sea)

• ACSR: Insert the steel in the core to have more tension.

10

Assumption University Thailand

High Voltage CablesInsulated Wires

• For safety and prevent interruption

• PIC: Partial Insulated Cable

• SAC: Space Aerial Cable

• XLPE: Cross-linked

Polyethylenehttp://www.huffingtonpost.co.uk/2012/03/26/northamptonshire-fire-crew-hot-air-balloonist_n_1378971.html

11

Assumption University Thailand

High Voltage CablesInsulated Wires - PIC

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/33kv_oc.pdf

12

Assumption University Thailand

High Voltage CablesInsulated Wires - SAC

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/35kv_cc.pdf

13

Assumption University Thailand

High Voltage CablesInsulated Wires - XLPE

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/115kv_ce.pdf

14

Assumption University Thailand

Cables for Low Voltage

• Below 750V

• Conductor: Aluminum or Copper

• Insulator: PVC or XLPE

• Number of Conductor: 1 or many

• Special Type to suite the need: Fire Retardent

15

Assumption University Thailand

Cables for Low Voltage(see pdf)

• PVC

– NAY (aluminum)

– THW

– VAF

– VCT

– NYY (double shealth)

• XLPE

– CV

• MI

• Fire Safety Cable

– Flame Retardant

– Fire Resistant16

Assumption University Thailand

Cables for Low VoltageFire Resistant Cable

• Flame Retardancy

• Flame Propagation

• Acid and Corrosive Gas Emission

• Smoke Emission

• Fire Resistance (Circuit Integrity)

17

Assumption University Thailand

Cables for Low VoltageFire Resistant Cable

• Fire Alarm System

• Building Automation System

• Emergency Lighting System

• Public Address System

• Standby Power System

• Computer Network System

• Closed Circuit TV System

• Elevators and Escalators System

• Fire Pumps and Pressurized Stairs

• Etc.

18

Assumption University Thailand

Assignments

• Take pictures of the cable that you can see and classify the types of those cables.

• Take pictures of the name-plates

19

Assumption University Thailand

Cable Selection

• Usage: Table 5-16 (EIT Standard 2001-51) for low

voltage cable

• Rated Voltage: 300V or 750V

• Rated Current

• Multiple Conductors

• Voltage Drop20

Assumption University Thailand

Cable Selection – Rated Current

• Size of Conductor

• Type of Insulator

• Ambient Temperature

• Installation Conditions:

– Calculation: BCC - Technical_data_Cable

– Table: BCC - InstallationGuide, AS_NZS_3008.1.1_2009

21

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.1)

Handout: BCC - Installation Guide.pdf

22

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.1t)

Handout: BCC - Installation Guide.pdf

23

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.2)

Handout: BCC - Installation Guide.pdf

24

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.2t)

Handout: BCC - Installation Guide.pdf

25

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.3)

Handout: BCC - Installation Guide.pdf

26

Assumption University Thailand

Cable Selection – Rated CurrentInstallation Conditions (3.3t)

Handout: BCC - Installation Guide.pdf

27

Assumption University Thailand

Cable Selection – Rated CurrentNumber of Cables in a Conduit

Handout: BCC - Installation Guide.pdf

28

Assumption University Thailand

Cable Selection – Multiple Conductors

• To increase the rated current

Handout: BCC - Installation Guide.pdf

29

Assumption University Thailand

Cable Selection – Multiple Conductors

• Only for cable from 50 sq.mm. and up

• Same type of cables

• Same length

• Same wiring method

30

Assumption University Thailand

Cable Selection – Voltage Drop

• Voltage drop due to the impedance of the cable

• NEC

– Main incoming to load: no more than 5%

– Feeder: no more than 2%

– Branch Circuit: no more than 3%

31

Assumption University Thailand

Cable Selection – Voltage Drop

32

Zcable

Zload

220 V (AC)

Assumption University Thailand

Cable Selection – Voltage Drop

• Load: is from the consumption and power factor: or

• Cable: is from the table ( and )

– depends on the wiring configurations.

33

Assumption University Thailand

Cable Selection – Voltage DropCalculation

34

• Use the normal voltage divider in the calculation.

– =

– =

– ????

Assumption University Thailand

Cable Selection – Voltage DropCalculation

http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf

35

Assumption University Thailand

Cable Selection – Rated CurrentCalculation

36

http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf

Assumption University Thailand

Equivalent CircuitsImpedance: table for PVC cables

and

37

Size () Resistance()

Reactance()

2.5 7.400 0.155

4 4.625 0.141

6 3.083 0.131

10 1.850 0.121

16 1.156 0.113

25 0.740 0.107

35 0.529 0.103

50 0.370 0.100

Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�

Size () Resistance()

Reactance()

70 0.264 0.097

95 0.195 0.096

120 0.154 0.094

150 0.123 0.092

185 0.100 0.091

240 0.077 0.090

300 0.062 0.089

400 0.051 0.088

Assumption University Thailand

Cable Selection – Rated CurrentFrom Table

38

http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf

Assumption University Thailand

Cable Selection – General Rules

• 20% to 25% factor.

• Using current or VA (not power).

39

Assumption University Thailand

Cable Selection – Examples

• Water Heater 6kW

– in Air or in Metal Conduit

• Microwave 2,300VA

• Industrial Heater 40kW, 400V 3phase

– 40oC or 50oC

40

Assumption University Thailand

Cable Selection – Examples

• Motor 37kW, 400V, In=72A

– DOL & Star-Delta

• Motor 60kW, 400V, pf.=0.8

• Room

– receptacles 2.5kVA

– lighting 500VA41

Assumption University Thailand

Handout

• BCC - Installation Guide

• HELUKABEL - Installation Operating Conditions

• AS_NZS_3008.1.1_2009

42

Assumption University Thailand

• Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�• Thai Electrical Code 2002: EIT Standard 2001-51

• http://www.bangkokcable.com

• http://www.thaiyazaki-electricwire.co.th

• Electrical Installation Guide 2010: schneider-electric

Reference

43