hb959204500 t20 pss.pdf

43
Brush Electrical Machines Ltd. PO Box 18, Loughborough, Leicestershire, LE11 1HJ, England Telephone: +44 (1509) 611511 Telefax: +44 (1509) 610440 E-Mail: [email protected] Web Site: http://www.fki-et.com/bem I I n n s s t t r r u u c c t t i i o o n n M M a a n n u u a a l l PRISMIC T20 POWER SYSTEM STABILISER Manual No: HB959204500 Document No: TP0000376 Issue: A Date: 4 September 2003

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Page 1: HB959204500 T20 PSS.pdf

Brush Electrical Machines Ltd.PO Box 18, Loughborough, Leicestershire, LE11 1HJ, England

Telephone: +44 (1509) 611511 Telefax: +44 (1509) 610440E-Mail: [email protected] Web Site: http://www.fki-et.com/bem

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PRISMIC T20 POWER SYSTEM STABILISER

Manual No: HB959204500

Document No: TP0000376 Issue: ADate: 4 September 2003

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PRISMIC T20 Power System Stabiliser

Manual No: HB959204500 Issue: A Date: 4 September 2003 Page: 2 of 43

HB959204500 (A) T20 PSS.doc © Brush Electrical Machines Ltd. 2003

CONTENTS1 INTRODUCTION TO MANUAL ................................................................................................................. 4

1.1 General................................................................................................................................................ 41.2 How To Use The Manual .................................................................................................................... 41.3 Copies ................................................................................................................................................. 51.4 Feedback............................................................................................................................................. 51.5 Service & Spares................................................................................................................................. 51.6 Contact Address.................................................................................................................................. 51.7 Health & Safety At Work Act (1974).................................................................................................... 51.8 Protection And Monitoring Devices ..................................................................................................... 6

2 EU DIRECTIVES........................................................................................................................................ 73 INTRODUCTION........................................................................................................................................ 84 THEORY OF OPERATION ........................................................................................................................ 95 SPECIFICATIONS ................................................................................................................................... 126 T20 STRUCTURE AND SETTINGS ........................................................................................................ 137 INTERFACES........................................................................................................................................... 168 INSTALLATION ...................................................................................................................................... 18

8.1 Mounting............................................................................................................................................ 188.2 Wiring ................................................................................................................................................ 188.3 Connections To Excitation Controllers .............................................................................................. 18

8.3.1 General ...................................................................................................................................... 188.3.2 CAN Connections ...................................................................................................................... 188.3.3 Analogue Connections............................................................................................................... 198.3.4 PRISMIC A10 Excitation Controller Connections ...................................................................... 208.3.5 PRISMIC A30 Excitation Controller Connections ...................................................................... 21

9 PARAMETER SETTINGS........................................................................................................................ 229.1 ADC Analogue/Digital Converter....................................................................................................... 229.2 The Sensor Stage ............................................................................................................................. 23

9.2.1 Sensor Parameter Setting.......................................................................................................... 239.2.2 Checking Sensor Functions ....................................................................................................... 23

9.3 The PSS2A Functionality Stage........................................................................................................ 259.3.1 PSS2A Parameter Setting ......................................................................................................... 25

9.4 The Output Stage.............................................................................................................................. 269.5 The DAC Stage ................................................................................................................................. 269.6 Setting System Variables .................................................................................................................. 27

10 COMMISSIONING................................................................................................................................ 2810.1 Commissioning Tools ........................................................................................................................ 2810.2 Commissioning PC............................................................................................................................ 2810.3 Commissioning Procedures ............................................................................................................. 28

10.3.1 Preliminary Check...................................................................................................................... 2810.3.2 Check Of Sensors...................................................................................................................... 2810.3.3 Response Testing ..................................................................................................................... 28

10.4 Setting And Changing Parameters.................................................................................................... 2910.5 Automatic ADC Drift Compensation.................................................................................................. 3010.6 Event Logging And Data Recording.................................................................................................. 31

10.6.1 Save Presets To File.................................................................................................................. 3110.6.2 Save All Registers To File.......................................................................................................... 3110.6.3 View Event Log .......................................................................................................................... 3110.6.4 Set Event Log File...................................................................................................................... 3210.6.5 Analogue Data Logging ............................................................................................................. 32

10.7 Testing Signal Input And Internal Generation ................................................................................... 3410.7.1 Test Signal Setting..................................................................................................................... 34

10.8 Timed Testing Record....................................................................................................................... 3610.9 Testing Of Individual PSS Filter Branches........................................................................................ 3710.10 Fast ADC Data Acquisition ............................................................................................................ 38

10.10.1 Fast ADC Data Acquisition Enable/Disable ........................................................................... 3910.10.2 Fast ADC Data Acquisition Editing......................................................................................... 3910.10.3 Fast ADC Data Acquisition Recording ................................................................................... 40

11 MAINTENANCE ................................................................................................................................... 41

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11.1 Troubleshooting................................................................................................................................. 4112 APPENDIX A - SWITCH AND LINK SETTINGS................................................................................. 42

12.1 Switch SW1 - Signalling ................................................................................................................... 4212.2 Switch SW2 - Configuration ............................................................................................................. 4212.3 Links .................................................................................................................................................. 42

13 APPENDIX B - SPARE PARTS ........................................................................................................... 43

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1 INTRODUCTION TO MANUAL1.1 General

The purpose of this manual is to provide information and advice on supplied equipment.

Warning symbols used in the manual are as follows:

Mandatory Notice - Instruction to be followed.

Danger, General - Caution to be exercised. Appropriate safety measures to be taken.

Danger, Electricity - Caution to be exercised. Appropriate safety measures to be taken.

Danger, Harmful or Irritating - Caution to be exercised. Appropriate safety measures to betaken.

Information is given for guidance only. We do not accept any responsibility for the manner inwhich the information is used, nor the consequences thereof.

The design and manufacture of equipment is subject to constant review and as a result theinformation provided herein may vary from that manufactured.

Verbal or written modifications to the information contained herein have no legal status unlessconfirmed in writing by the Technical Director or his nominated deputy.

The manual, and any amendments, should be maintained for the lifetime of the equipment.

It is important that any persons responsible for equipment installation, commissioning,operation and maintenance, are provided with access to this manual.

1.2 How To Use The ManualPrior to undertaking any installation, commissioning, operation or maintenance activities on theequipment, it is recommended that this manual, and any associated documentation, should beread in their entirety in order to gain an understanding of system operation.

The manual is written as a 'stand-alone' document, but should be read in conjunction with anyreferenced or associated documentation.

All pages and topic headings are numbered for easy reference. Cross-reference(s) to associatedparagraphs and documentation is included where appropriate. When referencing particularparagraphs in communications, it is important to specify the Manual Number and the IssueReference.

Referenced drawings are attached as additional (unnumbered) pages.

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1.3 CopiesAdditional copies of the latest available version of manuals can be obtained from our ServiceDepartment at the contact address given hereafter. A nominal charge may be made for thisservice.

The information provided remains the copyright of Brush Electrical Machines Ltd., and is not to becopied or disclosed to a third party without the written approval of the Technical Director at thecontact address given hereafter.

1.4 FeedbackWe are constantly seeking to improve the quality and reliability of our products, and we activelyencourage user feedback.

Any comments should be addressed to your usual representative, or to our Service Departmentat the contact address given hereafter.

1.5 Service & SparesQuotations for Service and Spares can be obtained from our Service Department at the contactaddress given hereafter.

Authorised users can also access spare parts information provided at the Web Site address givenhereafter.

1.6 Contact AddressBrush Electrical Machines Ltd.PO Box 18LoughboroughLeicestershireLE11 1HJEngland

Telephone: +44 (1509) 611511 (Switchboard)Telefax: +44 (1509) 612436 (Service Department)

E-Mail: [email protected]@bem.fki-et.com

Web Site: http://www.fki-et.com/bem

1.7 Health & Safety At Work Act (1974)The information hereunder is supplied in accordance with Section 6 of the Health and Safety atWork Act 1974 with respect to the duties of manufacturers, designers and installers in providinghealth and safety information to Customers. The information advises of reasonably foreseeablerisks involved with the safe installation, commissioning, operation, maintenance, dismantling,cleaning or repair of products supplied by Brush Electrical Machines Ltd.

Every precaution should be taken to minimise risk. When acted upon, the following precautionsshould considerably minimise the possibility of hazardous incidents.

Delivery Checks: Check for damage sustained during transport. Damage to packing cases mustbe investigated in the presence of an Insurance Surveyor.

Installation: Where installation is made by engineers other than Brush Electrical Machines Ltd.personnel, the equipment should be installed by suitably qualified personnel in accordance withrelevant legislation, regulations and accepted rules of the industry. In particular, therecommendations contained in the regulations with regard to the earthing (grounding) must berigorously followed.

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Electrical Installation:

IMPROPER USE OF ELECTRICAL EQUIPMENT IS HAZARDOUS.

It is important to be aware that control unit terminals and components may be live toline and supply voltages.

Before working on a unit, switch off and isolate it and all other equipment within the confines ofthe same control cubicle. Check that all earth connections are sound.

WARNING: Suitable signs should be prominently displayed, particularly on switches andisolators, and the necessary precautions taken to ensure that power is not inadvertentlyswitched on to the equipment whist work is in progress, or is not yet completed.

Adjustment and fault finding on live equipment must be by qualified and authorised personnelonly, and should be in accordance with the following rules: Read the Instruction Manual. Use insulated meter probes. Use an insulated screwdriver for potentiometer adjustment where a knob is not provided. Wear non-conducting footwear. Do not attempt to modify wiring. Replace all protective covers, guards, etc. on completion.

Operation & Maintenance: Engineers responsible for operation and maintenance of equipmentsupplied under this contract should familiarise themselves with the information contained in thismanual and with the recommendations given by manufacturers of associated equipment. Theyshould be familiar also with the relevant regulations in force. It is essential that all covers are in place and that all guards and/or safety fences to protect

any exposed surfaces and/or pits are fitted before the machine is started. All adjustments to the machine must be carried out whilst the machine is stationary and

isolated from all electrical supplies. Replace all covers and/or safety fences before restartingthe machine.

When maintenance is being carried out, suitable WARNING signs should be prominentlydisplayed and the necessary precautions taken to ensure power is not inadvertently switchedon to the equipment whilst work is in progress, or is not yet complete.

When power is restored to the equipment, personnel should not be allowed to work onauxiliary circuits, eg. Heaters, temperature detectors, current transformers etc.

1.8 Protection And Monitoring Devices

WARNING: It is essential that any protection or monitoring device for use with generators orancillary equipment should be connected and operational at all times unless specifically statedotherwise herein. It should not be assumed that all necessary protection and monitoringdevices are supplied as part of Brush Electrical Machines Ltd. scope of supply.

Unless otherwise agreed, it is the responsibility of others to verify the correct operation of allprotection and monitoring equipment, whether supplied by Brush Electrical Machines Ltd. ornot. It is necessary to provide a secure environment that ensures operator safety and limitspotential damage to the generator and ancillary equipment. If requested, Brush ElectricalMachines Ltd. would be pleased to provide advice on any specific protection applicationissues or concerns.

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2 EU DIRECTIVES

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3 INTRODUCTIONThe PRISMIC T20 is a microprocessor based dual-input Power System Stabiliser thatimplements PSS2A functionality according to the IEEE Std421.5-1992, Article 8.2. Inputs to thestabiliser are speed, compensated frequency fC and electrical power P, which are signals arederived from current and voltage transformer inputs.

The PRISMIC T20 Power System Stabiliser is a compact unit with steel sheet cover designed forfixing on a cubicle mounting plate, and it is suitable for connection to automatic voltage regulatorsfor synchronous generators. The T20 is suitable for use on either brushless or static excitationsystems. The T20 enables easy connection to any analogue or digital AVR that acceVTs abipolar DC input for connection of a stabilising signal. A PC based HMI software tool is used forsetting and commissioning.

Figure 1: PRISMIC T20 Power System Stabiliser

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4 THEORY OF OPERATIONThe purpose of a power system stabiliser is to dampen low-frequency swings of the synchronousgenerator rotor by way of an automatic voltage regulator. These electromechanical swings can bedivided into three categories:

Inter-Area Mode: Typical frequency range 0.2 - 0.5 Hz Local Mode: Typical frequency range 0.7 - 2.0 Hz Inter Unit Mode: Typical frequency range 1.5 - 3.0 Hz

Damping coefficients of synchronous generators are influenced mainly by the generator design,reactance of connection of the generator to the grid, and setting and quality of excitation system.Generally modulation of generator excitation can produce transient changes in generatorelectrical active power, whilst steady state electrical power remains equal to the mechanical inputpower.

To supplement damping, a power system stabiliser must produce a component of electricaltorque that opposes changes in rotor speed. Suitable input signals for damping are electricalactive power Pe and shaft speed ω. The T20 dual input power system stabiliser uses both ofthese signals, which are evaluated from CTs and VTs situated on the generator terminals. Rotorspeed is replaced by the frequency of internal generator voltage fc. The magnitude of internalgenerator voltage is proportional to the generator field and its position is tied to the q rotor axis.Therefore shifts in internal voltage phasor position correspond with the generator rotor positionand the derived compensated frequency fc corresponds to the shaft speed. Derivation of theinternal voltage phasor Uc is depicted graphically in Figure 2.

q - axis

d - axisIt

Uc j xq It

Ut

0

Figure 2: Derivation Of Generator Voltages & Current

When disturbed by a sudden change in operating conditions, the generator speed ω and electricalpower Pe will vary around their steady state operating values. The relationship between thesequantities can be expressed in a simplified form of the swing equation. Using per unit power andsmall deviations in rotor speed, the swing equation can be expressed as:

( ) aem PH

PPHdt

d21

21 =−=ω

Equation 1 where Pm [pu] - mechanical power

Pe [pu] - electrical powerPa [pu] - accelerating powerH [MWs/MVA] - constant of inertiaω [rad/s] - angular speed of rotor

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By applying Laplace transform to Equation 1 and multiplying of both sides of equation with

Hs211

+ we obtain:

( ) ( ) ( )HssHs

Hssp

Hssp em

212

2121 ++

+=

Equation 2

Equation 2 can be represented graphically as:

Figure 3: Reconstruction Of Mechanical PowerThe actual signal of mechanical power obtained in this way can contain disturbances caused bylow frequency torsional oscillation. In order to eliminate them, the mechanical power signal ispassed through a ramp-tracking filter that dampens oscillations on frequencies higher thanapproximately 4Hz. The corresponding block diagram is shown in Figure 4.

Figure 4: Application Of Ramp Tracking Filter On Mechanical Power

After subtracting the signal Hs

Pe

21+ in accordance with Equation 1 and Equation 2 we obtain

accelerating power Hs

Pa

21+, that is suitable to dampen oscillations (See Figure 5).

Figure 5: Calculation Of Accelerating Power

HsHs21

2+

Hs211

+

ω

eP HsPm

21 +

+

+ ( )

N

MsTsT

++

9

8

11

HsHs21

2+

Hs211

+

ω

eP HsPa

21+

+

+ ( )

N

MsTsT

++

9

8

11

+

-

HsHs21

2+

Hs211

+

ω

eP HsPm

21 +

+

+

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In a practical power system stabiliser derivations of power and speed are used instead of actualpower and speed. Reason is to damp oscillations but do not influence control. Deviations are

realized by inserting of the washout filters with transfer function w

w

sTsT+1

, that eliminate the dc

components in both input signals. Phase shift of the output signal proportional to acceleratingpower must compensated for phase lag through generator, excitation and power system by twoor three stages lead - lag filters with transfer function (1+sTi) / (1+sTj). The final structure of thepower system stabiliser conforming with IEEE Std. 421.5-1992 is shown in Figure 6.

Figure 6: PSS2A Transfer Function

ω

1

1

1 sTwsTw+ 2

2

1 sTwsTw+ 61

1sT+ ( )

N

MsTsT

++

9

8

11

3

3

1 sTwsTw+ 4

4

1 sTwsTw+ 7

2

1 sTKs+

2

1

11

sTsT

++

4

3

11

sTsT

++

5

10

11

sTsT

++

3SK

1SK

P

VST

VSTM

-VSTM

++

+_

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5 SPECIFICATIONS1) Type

Dual Input PSS2A in accordance with IEEE Std421.5-1992, Article 8.2

2) InterfacingPower Supply: 24V (18 to 30V DC)Sensing Inputs: 3x 100V (90-120V), 2x 5 or 1A (Selectable)Testing Input: 1x ±10VLogic Inputs: 4x 24VLogic Outputs: 4x 24 - 125VAnalogue Output: 1x ±10VCommunication Ports: 1x RS232, 2x CAN

3) Electromagnetic CompatibilityEN 61000-4-2 (electrostatic discharge) level 3, category B.EN 61000-4-3 (radiated electromagnetic field) level 3, category A.EN 61000-4-4 (burst immunity test) level 3, category A.EN 61000-4-2 (surge immunity) level 3, category B.EN55011 (conducted noise) class A.

4) MechanicalEnclosure Protection: IP20Size (wxhxd): 272 x 153 x 48mmWeight: 1.32kgFixing: Cubicle mounting plate 4 x M5 nuts

5) EnvironmentalOperating Ambient Temperature: -25°C to 55°CStorage Ambient Temperature: -40°C to +85°CRelative Humidity: Up to 90% non-condensing

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6 T20 STRUCTURE AND SETTINGS

Figure 7: T20 Internal StructureThe T20 structure is shown in Figure 7. The main functional blocks (from signal input to signaloutput) are as follows:

1) ADC - Analogue/Digital ConverterSignals from voltage and current sensing inputs connected to VTs and CTs on generatorterminals are accurately sampled by six channel simultaneously acting 12 bit ADC withsample rate 24 samples per cycle.

2) SensorBlock of sensors uses sampled values to calculate input variables of power system stabiliser: P active electrical power fc frequency of internal generator voltage

Other generator electrical quantities for testing, commissioning and diagnostics purposes arecalculated simultaneously: Ut generator terminal voltage Ut1, Ut2, Ut3 generator terminal voltage in individual phases It generator terminal current It1,It2,It3 generator terminal current in individual phases S generator apparent power Q generator reactive power f frequency of generator terminal voltage fi phase angle between Ut and It

Voltage, current, power and frequency is evaluated per unit, with 100% corresponding to thegenerator nominal values

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3) PSS2AThis block includes a dual-input power system stabiliser according to the IEEE Std421.5-1992. Stabiliser inputs are speed, compensated frequency fC and electrical power P. Thetransfer function is shown in Figure 8.

Figure 8: PSS2A Transfer FunctionWhere:

fC compensated frequency, frequency of internal generator voltageKS1, KS2, KS3 stabiliser gainM, N grade of torsional filterP active electric powerT1, T3, T10 phase lead time constantT2, T4, T5 phase lag time constantT6,T7 low pass filter time constantT8,T9 torsional filter time constantsTw1,Tw2,Tw3,Tw4 washout time constantV1,V2,V3,V4,V5,V6 power system stabiliser internal variablesVST power system stabiliser outputVSTM,-VSTM power system stabiliser output limit

4) DiagnosticsThis block includes three functions: Sensor diagnostics PSS Output diagnostics Hardware diagnostics

When failure in evaluated PSS output status is changed and PSS output is disconnected fromAVR input.

1

1

1 sTwsTw+ 2

2

1 sTwsTw+ 61

1sT+ ( )

N

MsTsT

++

9

8

11

3

3

1 sTwsTw+ 4

4

1 sTwsTw+ 7

2

1 sTKs+

2

1

11

sTsT

++

4

3

11

sTsT

++

5

10

11

sTsT

++

3SK

1SK

fC

P

VST

V1 V4

V2

V5

V6

V3

VSTM

-VSTM

++

+_

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5) Control LogicThis block provides soft switching of the power system stabiliser with the respect to T20commands, T20 diagnostics, the level of active power and frequency deviation.

6) DAC12 bit digital DAC converter with a voltage output in the range -10V to +10V is used forconnection of the stabilising signal to the AVR input.

7) Testing InputTesting input is used for connection of external signal, measuring range is ±10V, input signalis sampled by 10 bit ADC. A 10V input signal corresponds with 0.1pu (1pu = voltagereference setting). Usage of testing input is described in Clause 10.7.

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7 INTERFACESThe interconnection of T20 is designed to be safe and easy. Connectors of following types areused: CON1-CON4: RJ10 MALE CON5: D- SUB 9F CON6,CON7: COMBICON Spring Plug FKCT2,5/18-STF (included in delivery)

Plug features: plug fixing: screw flange, vibration resistant wire connection: spring-cage number of positions: 18 Conductor size: solid/stranded, 0.2 …2,5mm2 testing: testing plug 2 or 2.3mm

T20 interfaces are illustrated as follows:

Figure 9: T20 Interfaces1) Feeding - CON7:13 to 18

24Vdc (18 to 30V)Testing voltage 500V, 50Hz/1minConsumption < 0,5A, internal resetable fuse 1,5A

2) Voltage Sensing Inputs - CON6:1 to 33x, 100V, (nominal 90-120V, 50 or 60Hz)Testing voltage 2000V, 50Hz/1minBurden<0.5VA

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3) Current Sensing Inputs - CON6: 7 to 132x 5A or 2x 1ATesting voltage 2000V, 50Hz/1minBurden<0.5VA

4) Test Input - CON6:15,16 ±10V 10 bit resolution (galvanically separated)Testing voltage 500V, 50Hz/1minInput Resistance 100kΩ

5) Analogue Output - CON7:11,12±10V galvanically separated 12 bit resolutionTesting voltage 500V, 50Hz/1minLoad resistance >2kΩ

6) Digital Inputs - CON7:1 to 54x 24 V DC, common 0V terminal (only voltage free contacts required)Testing voltage 500V, 50Hz/1min

7) Digital Outputs - CON7:6 to104x 24V DC up to 125V DC, one pole is connected to common terminalTesting voltage 1500V, 50Hz/1minContinuous current <0.12A, short circuit protection

8) Commissioning Port - CON5RS232 galvanically separated, Tx, Rx only, using 9way D male connector.Testing voltage 500V, 50Hz/1min

9) CAN Port 1 - CON3, 4CAN port for communication of bias signal to excitation controller as alternative to analogueoutput. 12V power supply is included for feeding of CAN network, port is non separated.

10) CAN Port 2 - CON1, 2CAN port for auxiliary communication links, galvanically separated, external feeding +12Vnecessary Testing voltage 500V, 50Hz/1min

11) LOCAL SIGNALLING - LED1…LED5, SW1T20 is equipped with five signalling LED's and accessible switch SW1, the meanings of LED1to 4 are explained in the table on the T20 front panel, see Figure 10 below.

Figure 10: T20 Front Panel

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8 INSTALLATION8.1 Mounting

Equipment is designed to be cubicle mounted on a plate. Fixing is provided by means of four M5screws. For drilling and required space see Figure 11.

115

153

4 x M5

12

7

272

10 252

Space for mounting

PRISMIC T20Power System Stabiliser

Figure 11: Mounting Details

8.2 WiringIt is recommended that the equipment is installed in accordance with the general practicesoutlined in IEC 61000-5-2 1997 and 61000-5-6.

For excitation systems, for EMC purposes, signal and power cables may be classified as follows: High level signal cables - Voltage and current sensing. Low level signal cables: Analogue input terminal of AVR such as analogue output, testing

input, communication cables (Individual shielded twisted pairs are recommended for thesesignals).

Low frequency power cables: connections to auxiliary power supply, logical I/O.

8.3 Connections To Excitation Controllers8.3.1 General

T20 connections to the AVR and associated devices are provided by means of the interfacesspecified in Section 7.

The AVR input gain KS4 (See Figure 7) can be set within range -5 to +5 (in 0.01 steps) which issuitable for most excitation controllers. These KS4 settings work with PSS analogue outputs andCAN communications.

To verify the correct polarity, the PSS internally generated positive step testing signal can beused. A step increase in excitation current should be seen when the step signal is applied.

8.3.2 CAN ConnectionsT20 CAN output connections are used as an alternative to analogue output connections for theinput signal to modern AVR's such as the Brush PRISMIC A10 excitation controller.

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8.3.3 Analogue ConnectionsFor AVR's having a suitable analogue input, such as the Brush PRISMIC A30 excitationcontroller, the T20 analogue output connections can be used. For optimal performance thefollowing AVR analogue input parameters are necessary:

Input range: ±10V DCInput resistance >2.2kΩGain of analogue input = 0.2* (gain of reference setting signal should be 1).

* This value of gain provides best utilisation of T20 DAC and AVR ADC converters. A gain ofanalogue input in the range 0.2 to 1 can be used, but this may not provide optimal performance.

The total gain of the stabilising signal (AVR input gain x KS4) must be equal to 1 as illustrated inthe following table.

AVR Input gain 0.2 0.25 0.5 1KS4 - PSS Output Scaling 5 4 2 1Total Gain 1 1 1 1

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8.3.4 PRISMIC A10 Excitation Controller Connections

Figure 12: Connection Of A10 Excitation Controller To T20 (1A Current Sensing Inputs)

Figure 13: Connection Of A10 Excitation Controller To T20 (5A Current Sensing Inputs)CAN Cable Part Nos:

Standard: 963245901 (2m) or 963245902 (4m)Mod.A: 963245903 (2m) or 963245904 (4m)

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8.3.5 PRISMIC A30 Excitation Controller Connections

Figure 14: Connection Of A30 Excitation Controller To T20 (1A Current Sensing Inputs)

Figure 15: Connection Of A30 Excitation Controller To T20 (5A Current Sensing Inputs)

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9 PARAMETER SETTINGSThe HMI software tool (See Section 10) is used for the setting of parameters and commissioning.HMI screens are divided according to the T20 main functional parts detailed in Section 6.

9.1 ADC Analogue/Digital ConverterSignals from VTs (voltage transformers) and CTs (current transformers) connected to T20 inputsare galvanically segregated by miniature accurate transformers which are sampled by asimultaneously acting six channel ADC. Channels CHA0, CHB0 and CHC0 are used to samplegenerator terminal voltage. Channels CHB1, CHC1, CHA1 are used to sample generator terminalcurrent.

For primary calibration of a new unit, eight adjustable parameters are used as illustrated in Figure16. The first six parameters are drift compensations of individual channels, which can be adjustedaccording to the instruction in Clause 10.5. The remaining two parameters calibrate generatorterminal current and generator terminal voltage measurements: Ut = 100% under T20 input voltage 100V and KUt=1 (See Figure 17) It = 100% under T20 input current 5A or 1 A and KIt =1 (See Figure 17)

Figure 16: ADC SettingsThe ADC variables window (See Figure 17) can be used for checking ADC variables and settingdrift compensation.

Figure 17: ADC Variables

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9.2 The Sensor Stage9.2.1 Sensor Parameter Setting

Sensor parameters are used for calculation of per unit variables for the PSS2A block from ADCoutputs. Four parameters (see Figure 18) must be set:

fn - generator nominal frequency: 50 or 60Hz

Ut scaling factortIN

Ut UK 100= , where UtIN is voltage at T20 terminals at generator nominal

terminal voltage.

It scaling factortIN

It IK 5= for 5A input range or

tINIt I

K 1= for 1 A input range, where ItIN is

current into T20 terminals at generator nominal terminal current. Xq machine reactance - quadrature axis saturated synchronous reactance.

Figure 18: Sensor Setting

9.2.2 Checking Sensor FunctionsTo check sensor functions there are three windows available. These are:

Sensor Variables. Sensor Outputs. Sensor Diagnostics.

The sensor variables window (see Figure 19) includes values of individual phase voltages andcurrents and value of terminal frequency. When phase measurement is enabled, values of phasedelays between first phase of voltage Ut1 and other phase voltages and currents are shown. Thisinformation is useful to check the correctness of T20 input signals from generator VTs and CTs.

Figure 19: Sensor Variables

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The sensor outputs window (see Figure 20) includes the following calculated output variables: Ut generator terminal voltage It generator terminal current S generator apparent power P active electrical power Q generator reactive power FI phase angle between Ut and It f frequency of generator terminal voltage fc frequency of internal generator voltage

Figure 20: Sensor OutputsThe sensor diagnostics window (see Figure 21) includes results of diagnostic tests: Ut threshold terminal voltage level is sufficient for calculation of output variables It threshold terminal current level is sufficient for calculation of output variables Ut symmetry terminal voltage symmetry It symmetry terminal current symmetry Ut range terminal voltage is in generator operating range

Figure 21: Sensor Diagnostics

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9.3 The PSS2A Functionality Stage9.3.1 PSS2A Parameter Setting

The PSS2A setting parameters are shown in Figure 22 below.

Figure 22: PSS2A SettingsFor checking of PSS2A input, output and internal variables it s possible to use the PSS2Avariables window (see Figure 23). It is also possible to check value of T20 control bits in the samewindow.

Figure 23: PSS2A Variables

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9.4 The Output StageThe output window (see Figure 24) shows the following parameters: Output Scaling KS4

KS4 enables fine set of output gain to accommodate T20 to individual AVR types (see Clause8.3). KS4 can be set for polarity and parameters on both analogue and CAN PSS outputs.

Pmin Minimum Active PowerPmin specifies level of active generator power for automatic PSS switch ON, below this levelis PSS OFF. Active power is a PSS input variable and appropriate stabilising signal can notbe generated for values close to zero.

PSS Output DiagnosticsEvaluates output from PSS2A block, when the Error Level of PSS Output is overridden fortime higher than Delay of PSS output Diagnostics. When a failure is evaluated the output ofPSS is disconnected from AVR input.

Time Ramps For Soft Switch ON/OFFTo provide soft switch ON/OFF , the PSS output signal is multiplied by the signal from rampfunction that increases from 0 to 1 during ton in the case of PSS switching ON, or from 1 to 0during toff in the case of PSS the switching OFF, see Figure 7.

Figure 24: Output Settings

9.5 The DAC StageThe DAC stage window (see Figure 25) enables the analogue output to be set zero.

Figure 25: DAC Setting

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9.6 Setting System VariablesThe system variables window enables display of the following system variables (See Figure 26): SW version - Version number of the T20 software. Flash CRC - Flash memory control checksum. Switch 2 position - Actual position of the SW2 switch on board. Bxx time - Duration of the B-level computation (PSS logic computation – lower priority). Txx time - Duration of PSS algorithm computation (higher priority). CAN error - CAN error indicator (1=error). Reset counter - Counter of T20 resets. Time - T20 local time.

Figure 26: T20 System Variables

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10 COMMISSIONING10.1 Commissioning Tools

Standard RS232 Cable 9F/9F. HMI Software Package

10.2 Commissioning PCPC with Windows 95/98/2000 or XP operating system, and RS232 serial port.

10.3 Commissioning Procedures10.3.1 Preliminary Check

Prior to commissioning the T20, it is important to complete commissioning of the protectionsystem for the generator and associated power equipment. Having verified that these are correctthe following preliminary checks should be made on the power system stabiliser and AVR:

1) Visually check that the T20 has not been physically damaged during transit to site.2) Ensure that the T20 side fixing is solidly earthed (grounded).3) Check that the T20 is correctly connected to the AVR.4) Check that all wiring external to the T20 is secure and in line with the contract circuit diagram.5) Check the connection of the incoming voltage (24V DC)6) Check that the software version and check sum is correct7) Check that the sensing signals (CTs and VTs) are correct in polarity and phase angles.

The T20 is now ready for commissioning as detailed below. The following information should beread in conjunction with any specific contract commissioning instructions.

10.3.2 Check Of SensorsChecking of sensors is undertaken using the HMI with the loaded generator connected to thegrid. Use the Sensor Variables window (see Figure 19) to check values of phase currents, phasevoltages and frequency, and to check phase angles between voltages and currents. Values in thewindow must correspond both with the generator operating point and with the values provided bystation measuring instrumentation.

Symptom ActionWrong phase angles Verify connection of T20 sensing

inputs and correct as necessary.Difference in voltage between T20and instrumentation

Verify voltage scaling factor (SeeClause 9.2) and correct asnecessary.

Difference in currents between T20and instrumentation

Verify current sensing factor (SeeClause 9.2) and correct asnecessary.

Select the Sensor output window (See Figure 20) to check values of Ut (generator terminalvoltage), It (generator terminal current), P (active electrical power), Q (generator reactive power).Values in the window must correspond both with generator operating point and with the valuesprovided by station measuring instrumentation.

10.3.3 Response TestingExternal equipment or the built in analogue data logging feature (See Clause 10.6.5) can be usedfor response testing and verification of PSS settings. The built in analogue data logging testingsignal can be provided from an external device connected to the T20 tested input CON6:15,16, oran internally generated testing signal (See Clause 10.7).

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10.4 Setting And Changing ParametersThe setting and changing parameters facility is provided through HMI software package.

Figure 27: Setting And Changing Parameters ScreenTo change a parameter:1) Go to the Menu – Presets2) There are two kinds of presets Operator Preset (for Users), or Maintenance Preset (higher

level access – for software developers etc.).3) Choose Operator Preset – and select one of displayed options.4) The relevant table will appear.5) Right click on the line showing the parameter required to be changed.6) The Enter Password screen will appear.7) Type the Password and press OK button (See Figure 28).8) The Edit Preset window will appear (See Figure 29). Set the required change using the up

and down buttons, then press the Transmit button. This completes the change.

Figure 28: Enter Password ScreenHMI default passwords:

Operator password: 123456Maintenance password: 441509611511

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Figure 29: Edit Preset WindowThe Edit Preset window closes after approximately 60 seconds, or when closed manually. Whilstthe window is open other parameters can be changed, without the need for a password, byrepeating steps 5) and 8) above. Closing the Edit Preset window requires the password in orderto change a parameter.

10.5 Automatic ADC Drift Compensation

Warning: Disconnect all T20 AC inputs (current and voltage) before using this feature.

Warning: The use of this feature is recommended for commissioning purposes only and is notto be used during PSS normal operation.

During the ADC drift compensation, several measurements with zero inputs are made. Theaverage values obtained for each channel are used to compensate the output values in order tomaintain zero outputs.

To procedure for automatic ADC drift compensation is as follows:

1) It is recommended that the ADC Variables window is opened to confirm that changes madehave been completed (See Figure 30).

Figure 30: ADC Variables Window2) Click on the Modules icon in the lower left corner of the main HMI program window (See

Figure 31).

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Figure 31: Modules Icon3) A password input dialog will appear.4) Type in the correct Password and press the OK button.5) The Modules options window as shown in Figure 32 will appear near the Modules icon.

Figure 32: Modules Option Window6) Select the AD_ext Drift Adjust Enable option.7) A confirmation dialog will appear. Confirm your option if required.8) Following confirmation, the ADC drift compensation is done automatically.9) If required, check the results in the ADC Variables window.

Note: The ADC drift compensation value can also be set manually for each channel. It can be setin the Preset Display - T20 ADC Setting Table by following the parameter setting proceduredetailed in Clause 9.6.

10.6 Event Logging And Data RecordingNote: This clause describes how to record measured data and events and save them as a file todisk. The standard HMI trending feature can be used to view the actual measured value.

Enter the main HMI Menu - Logging to select one of the five options illustrated in Figure 33.

Figure 33: Logging Options

10.6.1 Save Presets To FileWhen chosen, a save file dialog appears. Enter the path and new filename. All actual presets(operator and maintenance) will be saved into this file – filename.csv.

10.6.2 Save All Registers To FileWhen chosen, a save file dialog appears. Enter the path and new filename. The contents of allHR registers will be saved into desired file.

10.6.3 View Event LogDisplays an event log window (content is automatically updated when event occurs). The eventshistory (T20 power ON’s, logical variables changes, control variables changes etc.) are stored.Two options are available:

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Set event log fileOpens a save file dialog to save event log to a desired file.

Clear log entriesAll log entries are deleted from the actual log file (but events logging still continues).

10.6.4 Set Event Log FileOpens a save file dialog to save event log to a desired file.

10.6.5 Analogue Data LoggingUp to four sets of recordings are possible, and each set can contain up to 8 recorded variables.Recorded data stored in the T20 memory can be transferred to a file on the User's PC on User’s ifrequired. Each variable sample is 2 bytes and the total size of the recording is limited by 32kB ofT20 memory.

Recording options can be configured. If configured improperly i.e. the recording options exceedthe available memory, it is automatically set the closest allowable configuration. Data alreadystored in the T20 memory are lost when the logging configuration is changed.

The Analog data logging feature is accessible through Menu - Logging - Analog data logging.When this feature is selected the following Analog data recording window appears:

Figure 34: Analogue Data Recording Window1) Recordings

SelectThis determines the record number to be downloaded from the T20. Only non-active(already stored) records can be downloaded. The record number that can be chosendepends on the actual recording configuration e.g. Record set 4 cannot be selected if thedata recording count is set 3 only.

Download Recording To PCPushing this button downloads the chosen records stored in T20 to the PC and saves itto a temporary file.

Save Recording To DiskThe Save File dialog appears and selected recording set number is saved to a specifiedfile - filename.csv. To save a record to a file:

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Select appropriate non-active record set number. Download recording to PC. Save recording to disk.

2) Trigger To Start Recording Automatic Trigger Variable

Displays the logical variable, which starts the trigger. The trigger is started when thelogical state changes from False to True.

Send Manual Start TriggerThe trigger can be started manually when this button is pushed. (In the current versionof software the trigger is started automatically. This button is reserved for use with futuresoftware versions.

Send Manual Stop TriggerThe trigger can be stopped manually when this button is pushed. The record stops whenSample count after is reached.

3) Recording ConfigurationDisplays the recording configuration. Data Recording Count

Number of sets of records (up to 4) Active Data Recording

Number of recording set to which data is actually being written. Only one recording setcan be active. It is active (and being continuously rewritten when full) until it is stoppedwith manual or automatic trigger and the sample count after is reached. The recordremains saved in T20 memory and the next set becomes active. The active datarecording set represents a circular buffer to which data is written. It also contains timeinformation so that it can be downloaded from theT20 in the correct order.

Sample Count Before TripNumber of samples which will be recorded before the trigger event.

Sample Count AfterNumber of samples which will be recorded after the trigger event. Note: The sum ofsample counts after and before should not exceed the maximum sample countassociated with one variable.

Sample Rate (ms)The rate of storing the samples to the memory (same for all variables, set in multiples of5ms intervals).

Variables 1 To 8Recorded variables (displayed HR reg. addresses and names)

4) Edit Recording ConfigurationWhen this button is pushed, a Password Enter dialog appears. Enter the correct operatorpassword (see Clause 10.4) and press the OK button, and the Analog data recording – editconfiguration window will appear (See Figure 35). The previously described Recordingconfiguration options can now be set (See Item 3) above. After completing the requiredsettings, push the Send recording configuration button. When the acknowledgementwindow appears, press OK to exit the Edit configuration window.

Note: After sending new recording configuration to the T20, all previously stored data recordswill be lost.

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Figure 35: Analogue Data Recording - Edit Configuration Window

10.7 Testing Signal Input And Internal GenerationFor testing purposes e.g. modulation of the AVR set value to evaluate PSS response, a testingsignal can be added to PSS output. The testing signal is added to the location shown in Figure 7,and can be external or internally generated. The testing signal, if enabled, is restricted by thesame conditions as the PSS parameters i.e. measured values within a certain range, appropriatelogical values, diagnostic OK etc.

1) Testing Signal Parameters Testing signal amplitude is set in % of Vref (AVR set value).

2) External Testing Signal Any analogue signal connected to analogue testing input CON6: 15,16. Its amplitude

should not exceed 5 V. It is sampled by 10 bit ADC, 10 V input signal represents 0.1 p.u (10 % of Vref). The external testing signal is limited by HMI TestAmpl variable, which is accessible and

configurable through the Menu – Presets – Operator Preset – T20 Test Signal Setting. Setting of this variable limits both internal and external testing signal amplitude (maximum

amplitude is 0.05p.u.).

3) Internal Testing Signal Internally generated sinusoidal or step signal. Amplitude can be set up to +5 % of Vref (TestAmpl HMI variable). Frequency can be set within range 0 - 10 Hz. A step signal is generated when zero frequency is set.

10.7.1 Test Signal SettingWhen the Presets - Operator Preset - T20 Test Signal Setting menu is selected, follow theprocedure detailed in Clause 10.4 (Setting And Changing Parameters) and the following windowwill appear which allows internal testing signal to be set:

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Figure 36: Test Signal Setting Window TestAmpl

Setting of amplitude of internally generated testing signal, also limits external testing signalamplitude.

TestFreqSetting of frequency of internally generated testing signal. Zero frequency represents stepsignal.

FTESTFilters Testing Status (See Clause 10.9).

FTGEXPFilters Testing Gain Exponent (See Clause 10.9).

Note: FTEST and FTGEXP are used to test individual PSS filter branches (See Clause 10.9). Fornormal testing signal generation the FTEST parameter should be set to zero.

1) Triggering Of The Testing SignalManual enable/disable. The signal is generated immediately after confirming enable option.

Go to Modules Icon, enter and confirm password then choose either the internal test signalenable/disable, or the external test signal enable/disable option, and confirm.

If both internal and external test signals are enabled in error, both test signals areautomatically disabled.

2) Test Signal Enable/Disable Click on the Modules Icon in the lower left corner of the main HMI window (Figure 30). A

password dialog appears. Type correct password and press OK button. Modules options window appears near the Modules icon (see Figure 32). Choose the appropriate option (enable or disable appropriate test signal). Confirm your option. Changes take place automatically.

3) Test Signal DisplaySelect Menu - Display - 7. T20 Test Signal Display and the following window will appear:

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Figure 37:Test Signal Display WindowSetting: Displays internal testing signal amplitude and frequency.Measuring: Displays the actual value of the testing signal.Test Data: Displays which testing signal is enabledRecord: See Item 0 below.Filters Testing: Displays the number of currently tested PSS filter block, value of its output

(Variable SIG2) and input (Variable SIG1) and set scaling gain constant (SeeClause 10.9).

10.8 Timed Testing RecordTimed Testing Record is a special record mode for testing purposes e.g. recording stepresponse, test signal response, or appropriate event at the right time.

This feature is accessible and configurable through Menu - Logging - Analog Data Logging.See Section 10.6 in particular Clause 10.6.5.

Timed Testing Record (when enabled) runs in the same way as normal Analogue Data Logging,including record configuration, saving the record etc. The only difference is that it is controlled(trigger stopped) by a special logical variable (the Testing Record Status variable) when a specialtrigger event occurs. Two conditions must be met to start this mode of recording:

1) Timed Testing Record - Enabled through Modules - Timed Testing Record Enable (seeFigure 31 and Figure 32).

2) Special logical control variable must be set - Menu – Logging – Analog Data Logging –EditRecording Configuration - Automatic trigger variable – Choose Testing Record Statusvariable from the list. And configure the other record properties according to Section 10.6.

After both conditions are met and the appropriate setting saved and changes confirmed, therecord automatically starts and its initial conditions are saved i.e. value of VSTM (PSS outputlimit), internal test signal status and external test signal status (enabled or disabled).

The logical variable Testing Record Status is to stop the Timed Testing Record when an eventoccurs and the Sample Count After is reached.

Events that stop the recording are: Change in the setting of VSTM (PSS output limit) during the record i.e. change from zero to

non zero value or vice-versa.

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Change in the Internal Test Signal Status. Change in the External Test Signal Status.

When stopped the record remains saved in T20 memory. Another recording set automaticallystarts and the new set of initial conditions are saved.

10.9 Testing Of Individual PSS Filter BranchesIndividual PSS filter branches can be tested by an internal or external testing signal when thespecial setting activated. During these tests, the PSS is algorithm disabled, and only the testedbranch, testing signal input and generation, and analogue data logging are activated. There is nolimiting of the filter output except for the output DAC converter range. Output of the tested filter isconnected to PSS analogue output and logged into memory. CAN communication is disabled.

Details of current testing configuration can be displayed through following windows:

Menu - Display - 7. T20 Test Signal Display (See Figure 36).Menu - Presets - Operator Preset - T20 Test Signal Setting (See Figure 37).

1) To test the filters, select the required testing signal. If an internally generated testing signal isselected set the parameters in accordance with Clause 10.7 and Figure 36. If an externaltesting signal is selected connect the signal to CON6: 15,16.

2) Choose the filter section to be tested. Four filter sections can each be separately tested. SeeFigure 8 in Section 6.

Select Menu - Presets - Operator Preset - T20 Test Signal Setting and follow theprocedure described in Clause 10.4 (Setting And Changing Parameters). The T20 TestSignal Setting window will appear (see Figure 36). Set the testing signal frequency andamplitude (if not already set) and choose the filter section to be tested by setting appropriateFTEST parameter as follows:

FTEST=1: Washout Filters Of Speed InputSee Figure 8. Filters between compensated frequency input and variable V1.FTEST=2: Washout Filters Of Active Power InputSee Figure 8. Filters between active power input and variable V2FTEST=3: Torsional (Ramp-Tracking) FilterSee Figure 8. Filter between variables V3 and V4FTEST=4: 3 Lead-Lag StagesSee Figure 8. Filters between variables V5 and V6FTEST=0Filter testing disabled, normal PSS function possible. Mandatory setting when filter testingfinished.

3) Additional filter output gain setting FTGEXP should be used for scaling the tested filter output.This should be set if the filter has too low or too high gain and the analogue output signal (orinteger converted stored data) becomes too small and noisy (and would be damaged by theDAC or integer conversion, resulting in insufficient resolution), or when it becomes too strong.Use this scaling to obtain a clear output for accurate verification of the filter’s transfer function(phase and amplitude). This scaling is then part of the filter transfer function. Note: FTGEXPis inactive when FTEST=0.

Go to Menu - Presets - Operator Preset - T20 Test Signal Setting and follow proceduredescribed in Clause 10.4 (Setting And Changing Parameters).

The T20 Test Signal Setting window will appear (See Figure 36). Set the testing signalfrequency and amplitude (if not already set), and choose the filter output scaling gain bysetting appropriate FTGEXP parameter (Can be set within the range -3/0/+3 as a logarithmicexponent i.e. the gain can be set 1/1000, 1/100, 1/10, 1, 10, 100, 1000.

4) Input testing signal to the filter (internally or externally generated testing signal) is inside T20stored under variable SIG1.

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Output of the tested filter is stored under variable SIG2. It is also connected to PSS analogueoutput CON7:11,12

These variables can be downloaded by both Analogue data logging and by Timed TestingRecord (which is a special case of Analog data logging feature).

5) Connection of the testing signal to the chosen filter input is accessible using the followingprocedure:Modules - Enter and confirm password - choose Internal test signal enable/disable orExternal test signal enable/disable option and confirm (See Clause 10.7).

6) Recording and downloading of the filter testing signal and output can be achieved by usingthe Analogue data logging feature or the Timed Testing Record feature. There are no specialconditions or exceptions. To configure, run and download the records as described inClauses 10.6.5 and 10.7.

The filter input signal is stored as SIG1 variable, filter output is stored as SIG2 variable. Theycan be selected in the record configuration.

When Timed Testing Record enabled, the record starts automatically after enabling thetesting signal input.

7) When the filter tests are finished, set the FTEST parameter detailed in Item 2) above, toFTEST=0 to enable the PSS continue functioning, and disable the testing signal input andgeneration.

Figure 38: Example Of Record Configuration Display During Filter Testing

10.10 Fast ADC Data AcquisitionFor commissioning purposes and external ADC measured signals troubleshooting, it is possibleto log measured data directly from the external ADC converter (measured terminal AC quantities).

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The main difference between this type of data acquisition and Analogue data logging asdescribed in Clause 10.6.5 is that a shorter sampling interval is possible using Fast ADC DataAcquisition. All six ADC channels (line voltages and terminal currents) have sampling rate 24samples per 1 net period, which results in a sampling period of 0.833ms (50 Hz. net) or 0.684ms(60 Hz. net).

For fast data acquisition analogue data logging, which has a minimum sampling period of 5ms,the displayed time scale in fast ADC data acquisition will not be valid, and logged traces will havethe wrong time scale i.e. displayed time will be Configured Sample Rate/Actual Sample Ratetimes longer. Samples are taken and stored 24/1 net period, but displayed with Set Sample Ratein the Analogue Data Logging configuration, thus all samples are displayed in correct order, butwith a longer time scale.

When Fast ADC data acquisition is active, the data from all six ADC channels are recorded (i.e.stored and displayed in the output file) in the order of Ut1, Ut2, Ut3, It1, It2, It3. The data isrecorded after drift compensation, in a signed integer form. When the reactive power is zero(Q=0) the voltage Uti is phase advanced by 30O compared to the current Iti (i = index of thephase).

10.10.1 Fast ADC Data Acquisition Enable/Disable1) Click on the Modules Icon in the lower left corner of the main HMI window (See Figure 31). A

password dialog appears.2) Type correct password and press OK button.3) A Modules options window appears near the Modules icon (see Figure 32).4) Select Fast ADext Data Logging Enable (or Disable as appropriate) and confirm. Changes

take place automatically.

Note: Enabling the Fast ADC Data Acquisition feature overrides the Analogue Data Loggingfeature. It only uses some of the Analogue Data Logging configured options.

Note: It is mandatory that the Fast ADC Data Acquisition feature is configured for 6 recordedvariables complete with any 6 existing variables names which are used to store the data obtainedfrom the ADC.

10.10.2 Fast ADC Data Acquisition EditingThe procedure for editing the Fast ADC Data Acquisition configuration is detailed hereafter. Theremainder of the logging process is the same as described in Clause 10.6.5.

Analog data logging – edit configuration ( When Fast ADext Data Logging enabled, SeeClause 10.6.5 and Figure 35.

Select Menu - Logging - Analog data logging - Edit Recording configuration

Data Recording CountEnter a valid value.

Active Data RecordingEnter a valid value.

Sample Count Before TripEnter a valid value.

Sample Count AfterEnter a valid value (200 samples recommended i.e. approximately 8 periods of netfrequency)

Sample Rate (ms)Not valid. This setting only affects the time scale of the output file, but physically the samplesare recorded with sample rate 24/1 net period. However, their displayed period will be the setSample rate i.e. displayed time will be (Sample rate/ Actual sample rate) times longer.

Variables 1 to 8Fill in the names of variables 1 to 6 (MANDATORY). A formal character is necessary to storethe names in the output file. Generally there can be any 6 HMI accessible variable names(even 6 of the same names). ADC data (6 channels) will be saved under these names to theoutput *.csv file.

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It is recommended to use variables Ut1, Ut2, Ut3, It1, It2, It3, because the logged variablesare really 3 voltages and 3 currents (but taken directly from the ADC - actual values ofvariables Ut1, Ut2, Ut3, It1, It2, It3 as used in the HMI represent effective values)

Automatic TripFormal character, not used.

After editing the configuration press the Send configuration button.10.10.3 Fast ADC Data Acquisition Recording

Select Menu - Logging - Analogue data logging and follow the same procedure as in Clause10.6.5. All options (including downloading the traces to the PC) work the same way. In case ofFast ADC data acquisition a manual start/stop trigger operation is assumed.

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11 MAINTENANCEThe T20 Power System Stabiliser is completely solid state apart from switches, and requires verylittle maintenance. It is recommended that the T20 is inspected approximately every 12 months tocheck for excessive dust build-up, and to confirm that all connections are secure. Excessivequantities of dust should be removed with a soft brush.

In common with generator protection systems, it is good practice to check the calibration and thecorrect operation of Power System Stabiliser annually. If required, Brush Service Departmentcan provide this service.

WARNING: Take anti-static precautions when handling cards. Ensure that you are earthed(grounded) by clipping a wrist strap or similar device to the earth connection fitted to themounting side fixings of the T20.

Electronic cards can be damaged by static discharge and should be carried in anti-staticprotective containers wherever practicable. They should always be stored and transported inanti static bags or boxes.

11.1 Troubleshooting

Symptom Test / Check Remedy ActionSW1- (in any position)LED5 does not lightPOWER ON ERROR

Measure voltage betweenterminals:a) X7: 18(+) and X7:15

Voltage should be 18-28VCheck the polarity

b) X7:17 (+) and X7:14Voltage should be in therange 17-28V

If voltage a) and b) is OKreplace unit.If voltage a) is OK and b) is not,disconnect wire X7:17. If H5 islit determine the cause ofovercurrent through X7:17,otherwise replace the unit

SW1 -1 positionLED1 is litSENSING ERROR

Use HMI to display generatorterminal voltages and currents(See Clause 9.2)

If existing voltages or currentsdo not have correct values andphase angles correct the T20input(s).

SW1-1 positionLED2 is litOUTPUT ERROR

Use HMI to display PSS2Ainput, output and internalvariables (See Clause 9.3)

Investigate and rectify asnecessary.

SW1-1 positionLED3 is litHADWARE ERROR

Use RESET pushbutton Replace the unit

SW1-1 positionLED4 is litCAN ERROR

Use HMI to display position ofSW switch (See Clause 9.6)

If SW2 is in position 4 (CAN isused for connection to the AVR)check cable between AVR andthe T20.

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HB959204500 (A) T20 PSS.doc © Brush Electrical Machines Ltd. 2003

12 APPENDIX A - SWITCH AND LINK SETTINGS12.1 Switch SW1 - Signalling

Position Meaning LED1 LED2 LED3 LED4 LED50 State Running Healthy1 Error Sensing Output HW CAN2 Commands ON Blocking3 Level OK Power Frequency4 Input CON7:1 CON7:2 CON7:3 CON7:45 Output CON7:6 CON7:7 CON7:8 CON7:96789

Power ON

12.2 Switch SW2 - Configuration

Position Meaning0 Testing - T20 piece test, testing rig is necessary1 Operation system only2 PSS2A for PRISMIC A30 AVR and other made AVRs3 PSS2A for PRISMIC A10 AVR4 Reserve5 Reserve6 Reserve7 Reserve89

Boot strap mode - loading of new program

12.3 Links

Link LK1 - CAN2(CON1, CON2) Terminating ResistorPOSITION A BResistor value 120R None

Link LK2 - CAN1(CON3, CON4) Terminating ResistorPOSITION A BResistor value 120R None

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13 APPENDIX B - SPARE PARTSCommissioning/Operational SparesTo be advised.

Strategic SparesTo ensure maximum generator availability, it is recommended that a spare T20 Power SystemStabiliser should be kept in storage. If ordered after the time of manufacture of the mainequipment, it is important that your order specifies the serial number of the original unit, to enablethe spare/replacement unit to be configured as the original.