HB959202000 A30 Excitation Controller.pdf

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Instruction Manual

PRISMIC A30 EXCITATION CONTROLLER

Manual No: HB959202000

Document No: TP00000021 Issue: JDate: 30 May 2003


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PRISMIC A30 Excitation Controller

Manual No: HB959202000 Issue: J Date: 30 May 2003 Page: 2 of 126

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

1.1 General................................................................................................................................................ 41.2 How To Use The Manual .................................................................................................................... 41.3 Copies ................................................................................................................................................. 41.4 Feedback............................................................................................................................................. 51.5 Service & Spares................................................................................................................................. 51.6 Contact Address.................................................................................................................................. 51.7 Health & Safety At Work Act (1974).................................................................................................... 5

1.8 Protection And Monitoring Devices ..................................................................................................... 62 EUROPEAN DIRECTIVES ........................................................................................................................ 73 INTRODUCTION........................................................................................................................................ 84 RATINGS ................................................................................................................................................... 95 FEATURES .............................................................................................................................................. 106 SPECIFICATION...................................................................................................................................... 12

6.1 A30-CON Card.................................................................................................................................. 126.2 A30-MON Card.................................................................................................................................. 186.3 Standby Control Card........................................................................................................................ 21

6.4 Utilities Card...................................................................................................................................... 246.5 A30-RACK1 Mainframe..................................................................................................................... 26

7 HARDWARE DESCRIPTION .................................................................................................................. 28

7.1 A30-CON Card.................................................................................................................................. 287.2 A30-MON Card.................................................................................................................................. 347.3 Standby Control Card........................................................................................................................ 367.4 Utilities Card...................................................................................................................................... 407.5 A30-RACK1 Mainframe..................................................................................................................... 41

8 SOFTWARE DESCRIPTION................................................................................................................... 44

8 1 A30 CON Card 44


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10.22 Static Interrogation ........................................................................................................................ 6411 USING THE WINDOWS HMI COMMISSIONING SOFTWARE........................................................... 6511.1 Setup Of the A30 Using An Alternative Power Supply...................................................................... 6511.2 PC Software Installation.................................................................................................................... 6511.3 Running the HMI Application............................................................................................................. 6511.4 Exiting the HMI Application ............................................................................................................... 6611.5 HMI Functions ................................................................................................................................... 6611.6 A30-CON Card HMI Displays Available........................................................................................ 6711.7 Logfile ................................................................................................................................................ 68

11.8 Saving Presets And Registers .......................................................................................................... 6811.9 Passwords......................................................................................................................................... 6811.10 Using The A30-CON HMI Displays ............................................................................................... 6911.11 A30-MON Card - HMI Displays Available...................................................................................... 7611.12 Using The A30-MON HMI Displays............................................................................................... 77

12 USING THE SCADA COMMUNICATIONS PORT .............................................................................. 8212.1 Protocol Data..................................................................................................................................... 8212.2 Physical Connections........................................................................................................................ 8212.3 Data Available ................................................................................................................................... 82

13 TRANSDUCER CALIBRATION PROCEDURE................................................................................... 8313.1 Line Voltage Calibration On The A30-CON Card ............................................................................. 8313.2 Field Current Calibration On The A30-CON Card............................................................................. 8313.3 Line Current Calibration On The A30-CON Card.............................................................................. 8313.4 Temperature Transducer Calibration on the A30-CON Card............................................................ 8313.5 Line Voltage Calibration on the A30-MON Card............................................................................... 8413.6 Field Current Calibration on the A30-MON Card .............................................................................. 8413.7 Line Current Calibration on the A30-MON Card ............................................................................... 8413.8 Temperature Transducer Calibration on the A30-MON Card ........................................................... 84

14 STEP RESPONSE TESTING............................................................................................................... 8514 1 Step Response 85


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1 INTRODUCTION TO MANUAL

1.1 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 betaken.

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

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

to be taken.

Information is given for guidance only and we do not accept any responsibility for the mannerin which 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 unless

confirmed in writing by the Technical Director or his nominated deputy


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1.4 Feedback

We are constantly seeking to improve the quality and reliability of our products, and weactively encourage user feedback.

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

1.5 Service & Spares

Quotations for Service and Spares can be obtained from our Service Department at thecontact address given hereafter.

Authorised users can also access spare parts information provided at the Web Site addressgiven hereafter.

1.6 Contact Address

Brush Electrical Machines Ltd.

PO Box 18LoughboroughLeicestershireLE11 1HJEngland

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

E Mail ser ice sales@bem fki et com
mailto:[email protected]:[email protected]


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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 maybe live to line and supply voltages.

Before working on a unit, switch off and isolate it and all other equipment withinthe confines of the same control cubicle. Check that all earth connections aresound.

WARNING: Suitable signs should be prominently displayed, particularly onswitches and isolators, and the necessary precautions taken to ensure that poweris not inadvertently switched on to the equipment whist work is in progress, or isnot 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 ofequipment should familiarise themselves with the information contained in this manual andwith the recommendations given in associated documentation. They should be familiar also

ith th l t l ti i f


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2 EUROPEAN DIRECTIVES


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3 INTRODUCTION

The PRISMIC A30 Excitation Controller is designed to control the excitation of a brushless generator.Incorporating a wide range of features, the A30 is housed in a 19" rack assembly requiring only externalinstruments and control switches to provide the complete excitation system as shown in Figure 1.

For setup and commissioning of the A30 a PC is required. PC based software and two serialcommunications cables are provided.

A copy of the factory test record and factory setup data is provided with the A30 in the form of a BrushQC(T)48 document. When provided with a Brush generator, the A30 factory setup data will be matchedto the generator. The QC(T)48 document should be available when commissioning the A30.


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4 RATINGS

Max. continuous output current: 20A

Max. 10 second output current: 30A

Excitation supply voltage: Single phase 110Vac to 330Vac

Excitation supply frequency: 50Hz to 480Hz

Auxiliary dc Supply: 24Vdc or 110/125Vdc +15%, -20%

Nominal sensing voltage: 100V to 120V selectable in 5V steps

Voltage sensing phases: Three phase with single phase option

Voltage sensing input burden: Less than 3VA per phase

Nominal generator frequency: 50Hz or 60Hz

Current transformer input nominal: 5A or 1A selectable

Current transformer input burden: Less than 1VA

Max field voltage for forcing: 75% of single phase supply RMS voltage

Accuracy of control: 0.5%

O ti t t 0C t 55C


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5 FEATURES

1) Complete System Housed In A Single 19 6U Rack

Includes power semiconductor and control circuits, power supply transformers, contactors forexcitation changeover and field suppression and field suppression resistor.

2) Independent Main And Hot Standby Excitation ChannelsThe unit contains two power semiconductor circuits, one acting as a hot standby to the other. Eachcircuit is controlled by an independent control card with automatic following to enable smooth

transfer from one to the other.

Transfer to the standby system is initiated by a separate monitor module in the followingcircumstances: Voltage monitoring (over/under voltage on generator terminals) Excitation monitoring (over/under excitation with time delays) Over flux monitoring Control card failure

The settings for the monitor module are selected to enable the normal limiter settings to operatefirst. (See Figure 2)


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9) VAr Control ModeAvailable when parallel running. Also incorporates VAr shed facility.

10) Soft Start FacilityAfter switching on excitation, line voltage is increased to the nominal level at an adjustable rate.

11) Fast Acting Field Current LimiterLimits excitation current to prevent excessive line current during power system faults.

12) Over Excitation LimiterUsing inverse time delay and temperature compensation if required, this facility is provided toprevent overheating of the generator rotor.

13) Under Excitation LimiterThis facility enables operation of the generator at maximum capability with a leading power factorbut avoiding the danger of the generator pole slipping.

14) Over Flux LimiterExcitation is controlled to ensure that generator line voltage is limited to a preset adjustable

voltage/frequency ratio to avoid over fluxing of the generator.

15) Selectable Standby System Control ModeThe standby system may be setup to operate in either Generator Voltage or Exciter Field CurrentControl Mode.

16) Rotating Diode Failure AlarmDetection of failed rotating diode or fuse is achieved by monitoring the ripple content of exciter fieldcurrent.


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6 SPECIFICATION

6.1 A30-CON Card

Unless stated otherwise, all adjustments on this card are made using the HMI.

6.1.1 Voltage Control

1) Three Phase Or Single Phase SensingSelected by a link.

2) Accuracy

0.5% of mean voltage.

3) Nominal Sensing VoltageSelectable from 100V to 120V in 5 volt increments.Frequency 50/60Hz 10%. Burden


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6.1.3 Over-Flux Limiter

The ratio voltage/frequency is automatically limited to between 1.00 to 1.20 perunit, the level being adjustable in increments of 0.001 per unit. (1 per unit voltageis the nominal sensing voltage referred to in Section 6.1.1 Item 3)).

6.1.4 Soft Start

After switching on excitation, line voltage is slowly increased to the nominal level.Ramping rate is adjustable from 5V/s to 25V/s.

Excitation should only be switched on by energising the Excite input after theAVR Main Electronics Supply has been applied. This should be achieved using aspeed detector switch, external to the AVR, which should be set to switch at 80%rated speed.

6.1.5 Speed Detection

The AVR provides excitation build up when 85% rated speed is reached.

Excitation is removed at 80% rated speed. Speed detection by the AVR uses PMGfrequency sensing. An external speed detector switch should also be fitted See6.1.4 above.

6.1.6 Power Factor Or Reactive Current (VAr) Control

1) PF/VAr Reference Adjustment Range

Power Factor: 0.6 lag to 0.9 lead in increments of less than 0.001VAr: 100% rated VArs lagging to 50% rated VArs leading at

nominal volts in increments of 1%.


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5) Automatic VAr SheddingIf the Power is reduced to zero while Power Factor Control is selected, the level ofVArs will automatically be reduced to a low level in order to maintain constantpower factor. Operation in this way will ensure that the Power Factor referenceremains unchanged when the set is shut down.

Operation of an external switch/relay will initiate automatic VAr shedding, and ifthis is invoked during the period that Power Factor control is also selected, VArshedding will occur irrespective of the power level. This is achieved by the PFcontroller reference being automatically set to unity. When this is done, the PF set

point of unity is stored when the set is shut down and is the setting used on thenext start.

If VAr shedding is invoked during the period that PF Control is not selected, VArshedding operates by internally turning on the VAr controller with its VAr referenceto zero VArs. This means that when VAr shedding by this method, any previousVAr reference is changed to zero VArs, and this value is saved on shut down andrecovered on the next start. If it is required to retain a particular non-zero VArreference setting, the VAr controller should first be turned off, then selecting PF

Control and VAr shedding simultaneously.

The rate of change of VAr or PF reference in response to a VAr sheddingcommand is determined by the programmed settings of the PF/VAr referenceadjustment rates referred to in 6.1.6 Item 3).

6) Selection Of PF/VAr ControlOperation of external switches or relays connected to the auxiliary dc supplywill initiate PF or VAr control. Internal dc supply isolation is provided. If PF or


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6.1.8 Under Excitation Limiter

1) Leading Reactive Current LimitThe limit at zero power and 100% volts is adjustable between 0.1A and 5.5Ain 0.01A increments. This covers the whole range for 1A and 5A CTs. The limitis automatically compensated in proportion to line voltage.

2) Limiting Level CurvatureThis is set by the external reactance control, which is adjustable between 0and 0.2 per unit in 0.01 per unit increments.

6.1.9 Fast Acting Field Current Limiter

1) RangeAdjustable from 2.5A to 30A in increments of 0.1A.

2) Time DelayLess than 0.05s.

3) Increased SensitivitySensitivity can be increased by a factor of 8 to enable checking at 12.5% ofnominal setting during commissioning.

6.1.10 Automatic Tracking of Standby Regulator

1) Standby FollowerWhen operating under Standby control and the sensing voltage is within thespecified range of the A30-CON card voltage reference, the reference of the

A30-CON is automatically adjusted so that line voltage and VArs do not


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LED 2 Watchdog dropout (program fails to cycle).

LED 3 Over excitation limiter operating.

LED 4 Under excitation limiter operating.

LED 5 PF control selected.

LED 6 In Main control this LED indicates Over Flux limiter operating.

In Standby control it indicates that Main has failed to match Standbywithin in a pre-set time.

LED 7 VAr shed selected.

LED 8 VAr control selected.

6.1.12 Control Card Output Signals

1) Limiter OperatingWhen Main channel control is selected a signal is provided to energise a relayon the Utilities card when either the over flux, over excitation or underexcitation limiter operates. When the standby channel is selected this signalindicates failure of the Main channel to match the standby channel within thespecified period.

2) Control Card Supervisory Output


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1k

47

8.6V

0.4V

9V

OutputTo A30

Con 1Con 2

Input FromPSS69V8

9

8

9 (A30 Terminal 108)

(A30 Terminal 107)

(Note: Pins 1 to 7 and Pins 10 to 16 are straight through)

Figure 3: A30-INT-PSS100 Interface Board Connections

With an input of 9Vdc from the PSS the output to the A30 will be 0.4Vdc.Therefore 9Vdc from the PSS will equate to a change in the AVR reference ofapproximately 10%. Note: When a PSS is being used 107 is positive and 108negative.

An analogue input transducer is also provided on the A30. If this is to be used thenLink 6B should be fitted. This uses the same input terminals as the PSS input andtherefore they cannot both be used at the same time. The analogue inputtransducer is used with special control software, Part No 963113801, that controlsthe voltage reference depending on the analogue input see Section 8.1.7.Note:


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Note that the AVR will not allow a set point to be adjusted beyond the

specified range, and that following receipt of a new set point, the rate ofchange from the previous to the new set point will be according to the valuesset during commissioning.

Note also that for the Leading PF Reference to be used, the PF Ref Leadingmode must be selected.

Set Points available are: Voltage Reference

VAr Reference PF Reference Lagging PF Reference Leading

3) Mode Selection Via CommsNote that unless Allow Mode Selection via the HMI has been activated via thecomms link, the mode will remain selectable by hard wired switch signals asnormal.

Note also that if Allow Mode Selection via the HMI has been activated, selectionof the mode by hard wired switch signals is inactive.

PF Reference Leading P F Control VAr Control VAr Shed Self Centre Voltage Reference Reset Monitors


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2) Trip Level

Adjustable between 1.00 and 1.25 per unit in increments of 0.001 per unit.

3) Time DelayAdjustable integrating time delay having a range of 10% seconds to 100%seconds in 1% second steps.

6.2.3 Under Voltage Monitor

1) Three Phase or Single Phase Sensing

Selected by a link. (selection must be same as Over Voltage Monitor)

2) Accuracy0.5% of mean voltage.

3) Trip Level

Adjustable between 70V and 120V in 0.1V increments.

4) Time Delay

Adjustable integrating time delay having a range of 2%s to 25%s in 1%ssteps.

5) Under Frequency InhibitAt line frequency of less than 80% nominal the Under Voltage monitor isinhibited.

6) Over Flux Limiter InhibitThe under voltage monitor is inhibited if the flux limiter on the A30-CON Card


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6.2.5 Under Excitation Monitor

1) Leading Reactive Current Tripping LevelThe tripping level at zero power and 100%V is adjustable between 0.1A and5.5A in 0.01A increments. This covers the whole range for 1A and 5A CTs.The trip level is automatically compensated in proportion to line voltage. Thisshould be set at least 10% greater than the under excitation limiter setting.

2) Tripping Level CurvatureThis is set by the `Xe' control and can be adjusted between 0 and 0.2 per unit

in steps of 0.01 per unit. This should normally be set to the same value as thelimiter.

3) Time DelayA fixed time delay is included to prevent spurious tripping due to transients.This can be set between 1s and 10s in 0.1s increments.

6.2.6 A30-MON Card Indications

LED 1 SpareLED 2 Monitor watchdog dropout (program fails to cycle).LED 3 Over Excitation monitor tripped.LED 4 Under Excitation monitor tripped.LED 5 Over Voltage monitor tripped.LED 6 Under Voltage monitor tripped.LED 7 Over Flux monitor tripped.LED 8 Standby Power Supply Fault.LED 9 A30-CON watchdog dropout alarm.


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6.2.10 Local Serial Communication Port

A serial communication port (COM 2) is provided for transmitting and receivinginformation to or from the HMI for commissioning and maintenance.

6.2.11 Remote Serial Communications Facility.

Remote communication with the A30-CON card in the AVR is particularly usefulfor adjustment of settings, selection of operating modes, and acquisition of data fordisplay on a remote terminal via a serial link. Remote serial communication with

the A30-MON card is less useful and not available on the standard system.

6.3 Standby Control Card

6.3.1 Field Voltage Control

In this mode (which is selected by links), field voltage is controlled to a constantlevel. Two links - selected ranges of 0-100V and 0-200V are available. Themaximum field voltage is approximately 75% of the PMG supply voltage.

6.3.2 Line Voltage Control

In this mode (which is selected by links), single-phase line voltage is controlled toa constant adjustable level. 10% QCC is provided to facilitate stable paralleloperation. A 250mA fuse, FS3, protects the voltage sensing input.

1) Line Voltage Setting Range

Sensing voltage adjustable from residual to 137.5V. VT burden


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6.3.7 Automatic Follower

When the Main AVR channel is operating, the output of the Standby regulator iscontinuously adjusted to match that of the Main AVR, so that on transfer to theStandby regulator, there is minimal change in excitation. Note that the travel timeminimum to maximum introduces a time delay to the follower action.

After selection of Standby control, the set point remains constant unless adjustedby the operator. If line voltage control is selected, regular adjustment of the setpoint of the Standby regulator is unnecessary. This will prevent large variations of

machine output voltage (or power factor if paralleled) as the load varies whichoccurs on manual regulators which control to a constant level of excitation.

6.3.8 Null Balance Indication

1) LocalTwo LED indicators are provided on the card which indicate `Manual High' and`Manual Low'. When the output of the Main and Standby control systems arematched, both LEDs are extinguished indicating balance between AVR and

Standby, irrespective of whether Standby or Main is selected.

2) RemoteProvision is made for a 500-0-500 micro amp; centre-zero, null balance meterto indicate balance between Main and Standby irrespective of whetherStandby or Main control is selected.

6.3.9 Field Voltage Limiter

A field voltage limiter is included which is adjustable from 25V minimum to 200V or


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6.3.13 Power Supply

The Standby board contains its own supply independent of the Main channel andMonitor. The power supply transformer primary is fused by FS1 and FS2(250mA). Link selected taps that cater for the following inputs, as seen in thefollowing table:

Links Selected Nominal Voltage Rating Over66-480Hz Range

Nominal Voltage Ratingat 50/60Hz

1, 3, 61, 5, 62, 3, 4

220 - 330V165 - 250V110 - 165V

250 10%187.5 10%125 10%

The unit is rated for 125% of the maximum for 1 minute to cater for over speedcondition.

6.3.14 Output Voltage

The card produces firing pulses that are supplied to a full wave, half-controlledbridge located in the mainframe. The maximum voltage that can be applied to thefield is approximately 75% of the PMG voltage at the input to the bridge.


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6.4 Utilities Card

6.4.1 Power Supplies

The card produces the following fused power supplies:

Card Supply Fuse Value

A30-CON 15V 5% FS4 250mA

+5V 5% FS3 1A

A30-MON 15V 5% FS2 250mA

+5V 5% FS1 1A

Hand-held Terminal +9V 1V FS5 100mA

Note: The Hand-held Terminal Supply is not used on the A30 ExcitationController, and may not be fitted on later versions.

The +5V supplies are each fitted with over voltage protection.

The supplies are designed to operate in conjunction with the transformer mountedin the mainframe, connected to the Auxiliaries Board and will operate over thefollowing voltage/frequency range:


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6.4.3 Relay Output Signals

The Utilities card contains relays described below having output signals that areaccessible on the rear plug assembly.

1) Contact RatingAll the relays on the Utilities card have the following rating:

Max switching Voltage 250V ac, 220V dcMax switching Current 2A ac, 2A dc

Max switching Capacity 125VA, 60WMin permissible Load 10mV dc, 10A

2) Diode Failure Relay (RL1)A normally de-energised relay which energises when a diode failure isdetected. One volt-free changeover contact is provided.

3) Monitor Tripped Relay (RL3)

A normally de-energised relay which is energised by a signal from the A30-

MON card when any of the following fault conditions are detected unless thegeneral alarm relay RL4 is energised.

Over Voltage Under Voltage Over Excitation Under Excitation Over Flux monitor A30-CON card microprocessor fault


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6.4.4 Utilities Card LED Indications

LED 1 15V A30-CON supply healthyLED 2 15V A30-MON supply healthyLED 3 5V A30-MON supply healthyLED 4 5V A30-CON supply healthyLED 5 General alarm relay energisedLED 6 Monitor relay energised

LED 7 Diode failure relay energisedLED 8 Unused

6.5 A30-RACK1 Mainframe

6.5.1 Field Suppression Contactor (FSC)

This contactor is mechanically latched in the excite or tripped condition. Whentripped, the ac supply to the thyristor circuits is disconnected and the field currentdecays through the field suppression resistor.

6.5.2 Field Suppression Contactor Slave Relay (FSCS)

Indication of the state of FSC is given by a volt-free changeover contact on FSCSwired to the outgoing terminal block. See below for contact rating.

6.5.3 Excitation Changeover Contactor (ECC)

The contactor is mechanically latched in the `Main' or `Standby' condition to selectthe required power circuit.


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6.5.8 Fuses

The following fuses are located as shown:

On auxiliaries board accessible from front:

FS1 Auxiliary dc supply +ve (5A)FS2 Auxiliary dc supply -ve (5A)FS3 A30-CON/A30-MON supply (2A)FS4 A30-CON/A30-MON supply (2A)

In mainframe behind hinged door:

FS5 Main channel power circuit semiconductor fuse (20ET)FS6 Standby power circuit semiconductor fuse (20ET)

6.5.9 Power Circuit Rating

1) Input Voltage

The nominal voltage of the PMG must be within the range 110V to 330V.

The PMG voltage should not fall below 75% of the nominal when supplyingthe maximum field current required under fault conditions.

2) Output VoltageThe maximum voltage supplied to the exciter field will not be less than 75% ofthe (loaded) PMG voltage supplied to the AVR.

3) Maximum Output Current


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7 HARDWARE DESCRIPTION

7.1 A30-CON Card

The control card contains the microprocessor and its associated digital addressing circuitry,digital counter timer, signal conditioning circuitry, thyristor firing pulse isolation circuitry, digitalinput and output ports, and serial communication ports, see Figure 4.

This board carries a smaller mezzanine board, the A30-M188, which contains the majority ofthe microprocessor-allied components. A large proportion of these are contained in an FPGA(Field Programmable Gate Array IC4) which is configured on power up by boot ROM IC3.The EPROM (IC11-A) containing the working software is also on this board.


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7.1.1 The Microprocessor And Its Associated Digital Circuitry

A 32MHz crystal (XTAL1) controls the Microprocessor (IC7) timing. It can be reseteither by the operation of the push button marked `Micro Reset' on the front panelor by the watchdog (1C1) whenever the software stops updating the watchdog.

The memory address circuits (IC6-A,IC8-A and IC9-A) produce a 17-bit address.128K of volatile RAM is fitted (IC10_A) and 8K of non-volatile memory EEPROM isfitted to store the commissioning and operator adjusted settings when the AVR isshutdown.

7.1.2 Serial Communication

Two serial RS232-C ports are available for local and remote communication.

A PC based HMI (Human-Machine Interface) can be connected to the localcommunication port via a `Comms' link to display and adjust contract settings.Provision is made for remote communication from a rear connector to enableadjustment of the settings and control modes via a SCADA link. This can also beused to display quantities measured by the control card.

7.1.3 Line Voltage Measurements


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The dc output voltage of IC3b is fed to a voltage to frequency converter (IC12)whose output frequency is proportional to the line voltage. This series of pulses isthen buffered and read into a counter timer, inside the FPGA on the A30-M188,over a fixed sampling period to provide a number which is proportional to linevoltage.

Typical voltage at TP9 is 4V - 6V dc at nominal line voltage.

7.1.4 Line Current Measurements


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7.1.5 Field Current Measurement Circuits


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7.1.6 Ambient Temperature Measurement

Figure 8: Temperature Measurement Circuits

Ambient temperature is measured using a 100 platinum resistance temperaturedetector (RTD) normally placed in the generator cooling air inlet


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The PMG voltage is isolated by transformer T2 on the auxiliaries board and

supplied to the A30-CON card where it is rectified by D11 & D12. The rectifiedsignal is compared to a negative signal and the difference amplified by IC7-D toproduce a narrow pulse at TP16 every zero crossing of the PMG voltage. Thissignal is used to reset a counter in the FPGA on the A30-M188.

A number calculated in the software (called DEMAND) is loaded into a countertimer every half cycle of the PMG voltage. Each time the PMG waveform passesthrough zero, the time begins to count, and when the counter reaches the numbercalled Demand the thyristor is fired via a pulse transformer.

When the firing pulse is produced the counter is reset and begins counting againon the next zero crossing of the PMG waveform.

7.1.8 Opto-Isolated Digital Inputs Of The A30-CON Card


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7.2 A30-MON Card

7.2.1 Introduction

The A30-MON card contains the microprocessor and its associated digitaladdressing circuitry, digital counter timer, signal conditioning circuitry, digital inputand output ports, and serial communication ports. A Mezzanine Board, the A30-M188 carries the majority of the microprocessor components. This board isidentical to the one on the A30-CON card except for the software contained in theEPROM.

It is similar to the A30-CON card, except it does not have the thyristor firing circuitand the PMG voltage input. See Figure 11.


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The memory address circuits (IC6-A,IC8-A and IC9-A) produce a 17-bit address.128K of volatile RAM is fitted (IC10_A) and 8K of non-volatile memory EEPROM isfitted to store the commissioning and operator adjusted settings when the AVR isshut down.

7.2.3 Serial Communication

Two serial RS232-C ports are available for local and remote communication. AnHMI can be connected to the local communication port via a `Comms' link to

display contract settings.

7.2.4 Line Voltage Measurements

Two transformers (T1 and T2) isolate the three-phase line voltage on the Utilitiescard before being supplied to the A30-MON card. The voltage is then rectified andbuffered by IC4d to produce a smooth dc voltage at TP4. Links 2A and 2B areused to select the gain and smoothing according to whether single or three phasesensing is required.

The dc output voltage of IC4d is fed to a voltage to frequency converter (IC3)whose output frequency is proportional to the line voltage. This series of pulses isthen buffered and read into a counter timer over a fixed sampling period to providea number which is proportional to line voltage.

Figure 5, Page 29 shows the route between the sensing terminals and the A30-MON card and typical voltage measurements with 110V sensing signal applied.

7.2.5 Line Current Measurement


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An error proportional to the temperature change is produced by the A30-CON card

which is then supplied to the A30-MON, where it is amplified by IC10c whoseoutput is connected to a voltage to frequency converter IC7 to give a frequencysignal which is related to RTD temperature.

Figure 8, Page 32 shows the circuitry used for temperature measurement withtypical voltage levels.

7.2.8 Opto-Isolated Digital Inputs

External control panel inputs such as field suppression contactor and monitorinhibit etc. are optically isolated from the A30 Excitation Controller electroniccircuitry. Each input is de-coupled to filter any transient spikes in the auxiliary dcsupply. It can be used for 24/48V or 110V dc supply, Link A being fitted for 24/48Vsupply, and Link B is fitted for 110/125V supply.

When a dc signal of the correct level is applied to an input, a 5V-isolated signal isproduced at the isolator output that is then applied to a digital input port of themicroprocessor.

Figure 10, Page 33 shows the circuitry used.

7.3 Standby Control Card

7.3.1 Introduction

The Standby control card contains all the electronic circuitry to control the Standbypower circuit housed in the mainframe. It is designed to be independent of the


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7.3.3 Digital Reference

IC4, 3 and 1 form a 12 bit up down counter controlled by the raise/lower logicdescribed in 7.3.10.

The 12 outputs are connected to a network of resistors R1 to R24 to produce areference signal that is adjustable in 4096 steps. This signal is supplied to theinput of amplifier IC10a whose output provides the reference current for theStandby regulator to the input of IC15b.

The counter is limited to a maximum count when the 8 most significant bits reachlogic `1'. Under this condition the output of IC12 falls to logic `0' forcing the nextclock pulse to reduce the count.

Similarly, when the counter is in its `fully down' state the outputs will be at logic `0'and provide minimum reference current.

At Standby minimum Pin 6 of IC4 and Pin 7 of IC1 are both zero which causes theoutput of IC6c to fall to `0' and turn on FET 2 giving indication of Standby at

minimum, whilst simultaneously removing further clock pulses via IC8a and IC8c.

7.3.4 Control Of Thyristor Firing

The thyristor in the Standby power circuit are phase controlled to provide therequired Standby output voltage. To control the instant of firing a triangularwaveform at TP4 that is synchronised to the PMG output voltage is compared to adc voltage at TP16.

When the voltage at TP4 exceeds that at TP16 the output of IC4d becomes


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Figure 13: Simplified Circuits Associated With Field Control And Line

Voltage Control

7.3.7 Stabilising

The field voltage signal present at C32 is smoothed by R74, 78, 79 (asappropriate) and C21 and is then conditioned by IC11b and associatedcomponents and supplied to the input of the error amplifier via C25, RV2 and R71.RV1 provides adjustment of the quantity of stabilising signal provided and RV2provides adjustment of the phase shift. Links 25, 26 and 28 are set according to


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Applying the dc supply to S1/9 or operating PB1 on the card lowers the digitalreference. In this case, TP9 is driven to a low level to make the clock pulsesreduce the counter setting.

When the raise or lower signals are removed the counter remains at its currentsetting.

7.3.11 Null Balance Detector

The null balance detector compares the instant at which the Main channel andStandby channel thyristor firing pulses occur and produces meter and LEDindications to show whether Standby is firing later than Main i.e. `STANDBY LOW',or earlier than Main i.e. `STANDBY HIGH'. Signals are also produced by the nullbalance detector to automatically match the firing angle of the Standby regulator tothat of the Main. This means that when Standby is selected from Main, it is set tothe correct level.

Conversely, when in Standby, control signals are produced by the null balancedetector, which are supplied to the A30-CON card to match the firing angle ofMain to that of Standby. By this means it is possible to run on Standby and checkautomatically that null balance can be obtained to indicate the state of the Mainchannel.

The null balance detector receives a firing pulse signal from the A30-CON card atS1/27, which is supplied, to IC14a. The firing pulse signal from the Standby pulsecircuit is supplied to IC14a and IC14b and are arranged to produce voltages atTP2 and TP3 which are equal when the firing angle of Main and Standby arebalanced


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7.3.13 Lower Limit And Standby At Minimum Indication

When the Standby reference is at minimum, Pin 6 of IC4 and Pin 7 of IC1 becomezero and the output of IC6c falls to zero preventing any further lower signals viaIC8a and IC8c. At the same time FET 2 is turned on, RL2 is energised, and LED 5turned on to give Standby at minimum indication.

7.3.14 Main AVR Power Supply Monitor

The Main channel 15V supply is applied to S1/19 and S1/21 and provides asignal to opto isolator IC12d. Loss of this supply causes RL1 and LED 4 to be

turned on via FET 1. A contact on RL1 causes FRS in the mainframe to energiseand select the Standby system.

7.4 Utilities Card

7.4.1 Introduction

The Utilities card contains 15V and 5V-dc power supplies, and line voltage

sensing transformers for the A30-CON and A30-MON cards. Relays associatedwith AVR logic, monitoring and indication facilities, together with the diode failuredetector are also included.

Figure 14 shows the circuitry that supplies the Utilities card with typical voltagelevels indicated. Allowance should be made when measuring transformer voltagesfor different PMG voltage levels to those shown.


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7.4.3 15V DC Power Supplies

The transformer T1 on the auxiliaries board supplies the PMG voltage on U1/15,U1/17, U1/19 and U1/21. The diode bridges DB1 and DB3 rectify this AC voltage.The unregulated dc voltage is then fed into two zener diodes to produce 15V forthe A30-CON and the A30-MON cards. The transistor VT1 and VT2 provide aconstant current source for the 15V supplies. LED's 1 and 2 provide indicationthat the 15V supplies are energised.

7.4.4 HMI Power Supply

A +9Vdc power supply for a hand-held terminal. The dc voltage present at theoutput of DB4 is fused by FS5 (100mA) and regulated at 9V by VT3, Z11 andassociated components before being supplied to a socket on the front plate of theUtilities card.

Note: This feature is not used on the A30 Excitation Controller, and may not befitted on later versions.

7.4.5 Relays Associated With The AVR Logic And Indications

Input signals to the card include monitor trip at U2/18, general alarm at U2/24, andlimiter on at U2/20, are given by the A30-MON card and the A30-CON card. Logic0 at these terminals causes the corresponding FET3, FET5 or FET4 to turn on.This in turn gives a corresponding LED indication and energises relays thatprovide external indications.

7.4.6 Diode Failure Indication


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The mainframe has a substantial heat sink at the rear on which are fitted two separate, half-controlled, single-phase bridges. These are used for the Main and Standby excitationsystems. Also mounted on the heat sink are a ballast resistor (BR) and a small PCB thatprovides voltage suppression for the two bridges.

Connections to the mainframe are via six, 16-way sockets. Two of these, mentioned above,are on the auxiliaries board while the remaining four are mounted on the Backboard and allprovide access at the rear. Facilities for connecting the higher current cables for the PMG andexciter field are provided on a DIN rail-mounted terminal block on the back of the unit.

Note:All the above connections are of the cage-clamp type and reference should be made toSection 9 for wiring suggestions.

A 25-way, serial communications socket is also provided at the rear of the unit.

7.5.1 Main Channel Power Circuit

In Main control, the PMG supply is connected via FSC-1, ECC-2, and ECC-3 tothe half controlled bridge comprising SCR1, SCR2, D1, and D2. The positive

output of the bridge is connected to the exciter field via DB1, FSC-2, FSC-3 andFSC-4. The negative of the exciter field is connected through current measuringresistors R7 and R8, to the negative of the Main and Standby power circuits whichare commoned.

A ballast resistance BR is connected across the field connections.

Note: The negative of the exciter field is earthed; the PMG mustnot be earthed


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2) Excitation Changeover Contactor ECC And Slave Relay ECCS

The Circuit Diagram (SeeAppendix E - Drawings) shows the contactors in the`Main channel' excitation state with the PMG connected to the Main powercircuit.

In this condition the Standby power circuit is disconnected from the PMG byECC-1 and ECC-4 and from the exciter field by DB2.

Contact ECCS-1, which is closed when Main is selected, provides a signal tothe Standby card S1/5 (via the Utilities card) to select Standby to the Main

follower mode, provided that the excitation limiter is not operating.

Contact ECC-7 provides a signal to the A30-CON card C2/17 when inStandby. This is used to set the A30-CON card in the `Standby follower' modeto make its output follow that of the Standby channel.

3) Fault Relay Slave - FRSIn the event of fault monitor operation or detection of loss of A30-CON cardpower supply, FRS is energised causing ECC to change state and select

Standby control.

4) Power Supply Relay - PSRThe presence of the auxiliary dc supply is monitored by PSR.

7.5.4 Field Current Transducers

Resistors R7 and R8, which are located on the Backboard measure exciter fieldcurrent. IC1 and IC2 amplify the low voltage signal before supplying it to the MainControl Monitor and Standby cards


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8 SOFTWARE DESCRIPTION

8.1 A30-CON Card

The mezzanine board on the control card has a boot ROM (IC3) and a software chip (IC11-A)fitted. The boot ROM, Part No 962618301, contains the necessary software to configure theFPGA (IC4) on power up. The software chip contains the control software, which can varydepending on the application.

To establish which control software is fitted consult the QC48 document. Alternatively, withthe A30 isolated, the control card can be removed to view the software chip (IC11-A) todetermine the Part No. and Version No.

To ensure the HMI software is compatible with the control software, the HMI software Part No.962609800 must be Version 2.1 or later.

8.1.1 Standard Control Software (963137401)

This software is supplied as standard on the control card. This software is basedon the original control software, 962616600, but the differential term has beenmodified. This was done to give an appropriate response when used with a powersystem stabiliser (PSS).

The software chip 963137401 may also be used if no stabiliser is present.

The software chip 963137401 should be used wherever possible forstandardisation and to allow for future use of a stabiliser even if not originally


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The new logic has been thoroughly factory tested. Further testing on site wouldunnecessarily risk damage to the generator and any connected equipment andshould be avoided. If a customer wishes to see the logic demonstrated on sitethen great care should be taken to ensure that any connected equipment canwithstand the temporary high voltages which would be applied and that nodamage is done to the generator. During a test the new logic will removeexcitation within approximately 6 seconds and the terminal voltage of a 13.8kVgenerator would be expected to reach about 18kV. In any tests it is important toensure that the excitation is not allowed to exceed 200% of the no load cold

excitation value for more than 15 seconds to guarantee no damage is done to thegenerator.

8.1.3 Widening The Range settings For Minimum & Maximum VRef

Included in A30-CON software chip 963137401 from version 3.01

The maximum value of VRef minimum limit was increased to 100% of VT nominaland the minimum value of VRef maximum limit was reduced to 100% of VTnominal. This was introduced to the standard chip following a requirement on a

particular site to limit VRef to a value closer to nominal than previously required.

8.1.4 Lowering Of The Minimum Overflux Limiter Setting

Included in A30-CON software chip 963137401 from version 3.02.

The previous minimum possible overflux setting of 1.08PU has been reduced to1.00PU.


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The analogue input to the AVR is connected to terminals 107 (-ve) and 108 (+ve).

On the A30-CON card Link 6B must be fitted and Switch 1-8 on the mezzanineboard must be off. To activate the analogue adjustment feature the Enable AnalogAdjust module must be selected from the HMI. The Panel/HMI digital input goinginto terminal 106 should then be selected to HMI. The voltage reference may nowbe trimmed by an analogue signal of 0 to 5 Vdc. The status of the analogue adjustfacility is indicated on the HMI. When the level of the analogue input is changedthe internal voltage reference is adjusted to the value determined by the analoguesignal. The rate of change is determined by the value set in the maintenancepresets Hreg 40061 (See Table 11 Page 74) during initial set up.

To commission the analogue adjustment of the voltage reference run with theanalogue adjust facility disabled and set the reference to nominal. Set theanalogue input to the AVR terminals 107(-ve) and 108(+ve) to 2.5v and adjustRV7 on the A30-CON card until V Ref via Analog Input shown on the HMI isequal to nominal volts. Confirm that when the analogue input signal is raised to5Vdc, V Ref via Analog Input increases to the maximum required value. Confirmthat when the analogue input signal is set to 0Vdc, V Ref via Analog Inputdecreases to the minimum required value. Set the analogue signal to 2.5Vdc,Enable Analog Adjust via modules button and check that variation of theanalogue signal produces the required variation of line voltage.

When analogue adjustment of the voltage reference is enabled, automatic PowerFactor or VAr control can be achieved by adjusting the analogue input signal.

If the Power Factor or VAr controller in the AVR is selected, adjustment of the setpoint is via the panel PF/VAr raise lower switches.

WARNING: When turning off automatic PF/VAr control system the set


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The VAr reference raise/lower switch functions are disabled and the

reference of the VAr controller will be automatically matched (within thepreset limits of 50% lead to 100%lag) to the machine output Vars. Onselection of VAr control mode, the reference will be the VAr value thatapplied when in the previous mode of control. On selection of VAr control,the VAr reference raise lower switches can be used to change the VArreference.

iii) When In VAr Control ModeThe Voltage reference will be automatically adjusted (within its preset

limits) so that there is no change in set point on transfer from VAr controlback to voltage control.

The PF reference raise/lower switch functions are disabled and thereference of the PF controller will be automatically matched (within thepreset limits of 0.9 lead to 0.6 lag) to the machine output PF. On selectionof PF control mode, the reference will be the PF value that applied whenin the previous mode of control. On selection of PF control, the PFreference raise lower switches can be used to change the PF reference.

b) On Standby Channel When Not In ControlThe Standby controller remains as standard, it will normally follow the outputof the Main Controller so that there is minimum shock on transfer to Standby.

8.2 A30-MON Card

The mezzanine board on the monitor card has a boot ROM (IC3) and software chip (IC11-A)fitted. The boot ROM, Part No 962617100, contains the necessary software to configure theFPGA (IC4) on power up and the software chip Part No 962616700 contains the monitor


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9 INSTALLATION AND MECHANICAL DETAILS, CARD FITTING AND REMOVAL

9.1 Installation

The A30 Excitation Controller is primarily designed for mounting into a standard 19" rackcabinet, but can be mounted on any sturdy panel with a suitable cutout. Where the unit isfitted into a cutout, some form of vertical stiffening is required behind the panel at each side ofthe cutout to support the cantilevered weight of the unit. For fixing dimensions, refer to theGeneral Arrangement drawing (SeeAppendix E - Drawings).

In addition to the above stiffening, it is advisable to either provide support under the rear of theunit, or to remove the unit during transit. If channels are provided either side of the AVR sothat the unit `sits' on these when in position, these will ease subsequent removal forinspection and maintenance.

A minimum of 300mm must be provided in front of the unit to allow the plug-in cards to befitted into the extender card when commissioning/fault finding.

9.2 Ventilation

It is important to ensure a free air space of 150mm above and below the unit to allowadequate thermal cooling of the unit. The top cover of the AVR is perforated to allowventilation, and should not be obstructed or covered.

9.3 Wiring To The A30 Excitation Controller

Connections to the AVR are made to a fixed terminal rail and to 6 removable plugs for lightcurrent connections The fixed terminals rail is suitable for cables up to 4mm

2and the 6 light

PRISMIC A30 E it ti C t ll


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A sound earth connection must be made to the earth terminal at the rear of the AVR.

Care should be taken not to allow debris to drop through the cover of the AVR duringinstallation.

9.4 Wiring To The Plug

Two methods of wiring the plug are recommended:

9.4.1 Method 1

1) Firmly secure the plug in the approximate final position (the ideal way to dothis is to insert the plug into its socket on the A30 Excitation Controller).

2) Strip back the insulation from the cable to a distance of 7mm to 8mm or fit acrimped ferrule if a contract requirement.

3) Insert the cage clamp tool or a small screwdriver into the terminal to open thecage clamp, and insert the cable ensuring that the clamp grips the conductorand that no stray strands are left exposed. See Figure 16.

PRISMIC A30 E it ti C t ll


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9.4.2 Method 2 (Using The Special Lever To Open The Cage Clamp)

1) Prepare the cable as described in 9.4.1 Method 1, Item 2).2) Holding the plug in the hand, depress the special lever and insert the cable

into the clamp. See Figure 17 and Figure 18.

Figure 17: Connection Of Conductors - Side Entry With LeverFor Self-Mounting



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9.7 Card Fitting and Removal

WARNING: Take anti-static precautions when handling cards. Ensure that you areearthed (grounded) by using a wrist strap or similar device. An earth connectionterminal is fitted in the centre or the front right hand mounting bracket of the AVRto which a wrist strap may be clipped.

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

Each plug-in card is fitted with a captive securing screw and a card insertion/ejectormechanism top and bottom.

To remove a card, first ensure that the mainframe switch SW1 is turned off if removing theUtilities, A30-CON or A30-MON card. The two retaining screws should be released and theejector levers gently pushed apart to jack the board out of the rack.

To insert a board, ensure that the mainframe switch is off if fitting the Utilities, A30-CON orA30-MON card. Push the ejector levers apart, and then insert the card in the correct position

until resistance is felt. Gently pull the levers together to draw the card into the rack. Finally,tighten the two captive screws.



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10 COMMISSIONING

10.1 EMC Installation And Operation Guidelines

The A30 Excitation Controller is industrial equipment and meets the essential requirements ofthe EEC EMC Directive 89/336/EMC when installed and operated in accordance with thefollowing guidelines.

10.1.1 Installation

The unit should be installed and connected so as to limit externally generatedinterference levels reaching it to within the levels defined by EN 50082-2(Immunity Generic Standard - Industrial).

This is achieved by mounting in a suitably constructed, earthed metal enclosureand wiring in accordance with the guidelines given in paragraph 10.1.3.

Additionally, other equipment installed in a common enclosure should not produceinterference in excess of the levels prescribed by EN 50081-2 ((Emissions Generic

Standard - Industrial).

10.1.2 Use Of Portable Communication Devices

Mobile phones and 'walkie talkies' should not be used near theequipment unless covers are fitted and panel doors closed.Furthermore, the antenna power of such transceivers should notexceed 5 watts and they should not be operated at a distance lessthan 1 metre from the equipment.



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Note: The advice given in the safety notice at the front of this Instruction Manualshould be followed during commissioning.

WARNING: If Standby control is to be used to excite the machine whilst runningshort circuited either for protection testing or drying out it is essential that it isselected for FIELD VOLTAGE control as described in 10.4.1 to 10.4.3, Item 1).Line current and exciter field current should be carefully monitored at this stage.

10.2 Pre-Commissioning Checks

Prior to commissioning the A30 Excitation Controller unit, it is important to completecommissioning of the protection system for the generator and associated power equipment.Having verified that these are correct the following preliminary checks should be made on theexcitation system:

1) Check that the PMG output is correctly wired and that PMG output is not earthed in itsterminal box.

2) Check that the sensing signals (CTs and PTs) are correct in polarity and phasing.

3) Check that exciter field is correctly wired.4) Check that all wiring external to the AVR is secure and correct to the contract circuitdiagram. Ensure that the earth stud is solidly earthed.

5) Visually check that the AVR has not been physically damaged during transit to site.Ensure that the contactors and other auxiliary equipment have not been disturbed andthat the internal wiring is secure. Check that the plug-in cards are correctly aligned andfully inserted.

6) Check that the correct links are fitted to the AVR as detailed in the A30 ExcitationController test certificate QC.48. Standby card links should be in the despatch position.



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10.3.2 Field Suppression Excite/Trip Signals

Simulate an exciter field trip signal and check FSC trips and FSCS de-energises.Check FSC energises when the trip signal is reset. Confirm correctexcite/suppression indication via FSCS-2 if applicable.

10.3.3 Standby Excitation Raise/Lower Switch

Confirm auxiliary dc +ve is present on Tm152 with respect to Tm153 whenStandby channel raise signal is given.

Confirm auxiliary dc +ve is present on Tm151 with respect to Tm153 whenStandby channel lower signal is given.

Note: The nature of the circuit ensures that the voltage present on the `opposite'terminal (e.g. TM 152 when a lower signal is given) is only about 0.5V less thanthe target terminal.

10.3.4 Main Excitation Raise/Lower Switch

Confirm auxiliary dc +ve is present on Tm100 with respect to Tm153 only whenMain channel raise is given.

Confirm auxiliary dc +ve is present on Tm101 with respect to Tm153 only whenMain channel lower signal is given.

10.3.5 Power Factor/VAr Raise/Lower Switch (If Applicable)

Confirm auxiliary dc +ve is present on Tm110 with respect to Tm153, only whenPF/VA i i l i i



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10.4 Check Standby Control

10.4.1 Check Excitation Isolator Is Off And Select Field Voltage Control.

Check that FSC is tripped (field suppressed) and Standby control selected. Ensurethat the Standby card is initially set to exciter field voltage control with the links setto give this condition (refer to the QC.48 document).

Turn off SW1 that is located on the mainframe

10.4.2 Run The Machine At Rated Speed

Check that the PMG voltage and the PMG frequency are in accordance with thatspecified on the QC.48 document. Close the excitation isolator to apply the PMGsupply to the AVR and reset FSC. Check that the following indicators are on:

Standby LED 3 Standby Power Supply HealthyLED 4 Control Power Supply FailedLED 5 Standby at Minimum

(Disregard others at this stage).

10.4.3 Check Performance On Field Voltage Control

1) Operate the Standby raise switch on the control panel for approximately 1second. Note that LED 5 goes off. Repeatedly pulse the raise switch, pausingfor a few seconds each time, and note that the exciter field current begins toincrease accompanied by an increase of line voltage. Confirm from the

it ti d t th QC 48 th t th li lt d t th l f



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10.4.4 Check Performance On Line Voltage Control

If Standby is to be left in Field Voltage Control Mode, (see QC.48 document) thisprocedure may be omitted

1) If Standby is to be operated in line voltage control fit the links specified in theQC.48 document.

2) Close the excitation isolator and reset FSC. Note that the Standby at Minimum(LED5) is turned on.

3) Operate the Standby raise switch (again repeatedly pulsing the raise switchand pausing for a few seconds each time) and observe gradual increase of

line voltage. Set the line voltage to nominal.4) The response of Standby voltage control can be set using stabilising controls

Stab Q (RV1) and Stab P (RV2), accessible through the front panel of thecard. A useful starting point is to set Q (RV1) and P (RV2) ten turns clockwise,reduce Q until the voltage begins to fluctuate, and then turn Q clockwise tostabilise voltage. When the AVR is stable, exciter field voltage should besteady. Trip FSC. Turn the excitation isolator to OFF.

5) The open circuit response can be optimised to give a particular response byuse of the 10% step change in reference PB3 on the card. Ideally, a digital

storage scope or UV response recorder should be used with a three phaseback-off unit. P and Q should be adjusted to give an open circuit singleovershoot of approximately 20% (of the step) with optimum rise time andsettling time. Further adjustments may need to be made on load to give aparticular response.

10.5 Check A30-CON And A30-MON Settings

Note: The design settings for the contract are given in the QC.48 document. Any deviation



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10.5.2 Set/Confirm Programmed Parameters On A30-CON card

Connect a PC, with the HMI software installed, to the control card using thecomms cable supplied. The cable should be connected from the serial port on thePC to comm port 2 on the front of the control card. Run the HMI software andconfigure it for the A30-CON. Ensure that the HMI is communicating by checkingthat the cursor in the bottom right hand corner of the screen is rotating. View themaintenance presets and check that they are the same as the design settings onthe QC48 document. If the card has been set up at the factory the settings shouldnot need changing as they are stored in E2PROM. If it is necessary to change anyof the stored settings see Section 11.10.5 for details. Using the HMI check that the

measured parameters are reading zero except for the sensing line voltage that willshow residual.

10.5.3 Set/Confirm Programmed Parameters on A30-MON card

Connect a PC, with the HMI software installed, to the control card using thecomms cable supplied. The cable should be connected from the serial port on thePC to comm port 2 on the front of the monitor card. Run the HMI software andconfigure it for the A30-MON. Ensure that the HMI is communicating by checking

that the cursor in the bottom right hand corner of the screen is rotating. View themaintenance presets and check that they are the same as the design settings onthe QC48 document. If the card has been set up at the factory the settings shouldnot need changing as they are stored in E2PROM. If it is necessary to change anyof the stored settings see Section 11.12.5 for details. Using the HMI check that themeasured parameters are reading zero except for the sensing line voltage that willshow residual.

10.6 Check Display Of Measured Parameters On The A30-CON And A30-MON Card



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2) Confirm that the settings of the stabilising controls (prop Gain, Integral Gain, Diff Gain) areset to the values shown in the QC (T) 48, unless optimum stabilising settings havepreviously been established. Select Main.Note: The PID stabilised settings given on the QC(T)48 are preliminary and may requireoptimisation on the contract but in the event that they are unsuitable settings of P=60,I=100 and D=50 provide a good starting point. Optimisation of the stabilising settings isdescribed in Section 14 of this Instruction Manual.

3) The PID stabilising settings given on the QC.48 are preliminary and may requireoptimisation on the contract.

This may be carried out initially by running the machine on open circuit and using the

VRef Step Up Test facility to produce a sudden increase in the reference voltage of theAVR. This is accessed via the 'Tests' button on the control HMI. The size of the step isadjustable and the default setting of 5% is recommended.

Typically, the settings will be adjusted to achieve an overshoot of approximately 20% (ofthe step) with an acceptable rise time. Use of the HMI to display overshoot and rise timewill help to select the best settings. The Trend Data which shows the shape of the voltagetransient will also be helpful but is not updated frequently enough to provide an accuratetrace of the voltage response.

In some cases it may be necessary to optimise the stabilising settings by performing loadapplication and rejection tests to check the response.

Once the required response is achieved, the response data from the HMI should berecorded.

10.9 Check The Voltage Range Of The A30-CON Card



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10.10 Check Soft Start

Remove excitation by de-energising the Excite input and momentarily energising the Tripinput to the FSC as shown on the A30 Excitation System Circuit Diagram - see Appendix E -Drawings. (The PMG isolator switch should not be used.)

Wait for 1 minute to allow line voltage to collapse completely.

Ensure that the Trip input to the FSC is de-energised and reapply excitation by energisingthe Excite input to FSC. Observe that line voltage builds up slowly without large oscillationsor any significant overshoot.

The soft start ramp rate may be adjusted if required.

10.11 Check For Smooth Changeover From Standby To Main Channel

Check that the null balance meter and standby LEDs indicate that standby is matched tomain and select standby. Lower standby and using the A30-CON HMI observe that Vreffollows V Sensing. Note that when the line voltage is below the minimum setting of V Ref, nofurther reduction is possible and LED1 on the CON card begins to flash continuously. Note

that after a delay, indication of mis-balance is given by LED 6 being turned on and also on theHMI.

Increase the setting of standby to rated voltage and observe that balance is once moreobtained, indicated by LED 1 being on continuously and LED 6 turning off. Select Main andcheck that there is negligible change in line voltage. If necessary the transient can be adjustedusing the Smooth Changeover P and D gain values in the maintenance presets.

10.12 Check/Set-Up Over Excitation Limiters And Monitors



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5) Enable the over excitation monitor. Check that the AVR trips to Standby afterapproximately 5 seconds.Note: If field current is limited to between 1.25A and 1.5A for this test, themonitor tripping time will be correspondingly longer.

6) Check that LED 3 on the A30-MON card is turned on.7) Turn off the X4 sensitivity on the A30-MON card. Reset the monitor using the

reset pushbutton.

10.12.4 Program Final Settings

1) Adjust the Over Excitation Monitor Set Point (Maintenance Presets) to the

level given in the QC.48 document.2) Turn off the Fast OEL x8 Sensitivity and then the OEL x4 Sensitivity on the

control card ('Modules' button).

Adjust the Fast OE Limit Ref (Maintenance Presets) to the level given in theQC.48 document.

Adjust the OE Limit at 0C (Maintenance Presets) to the level given in theQC.48 document.

3) Enable the OE Limiter ('Modules' button). Leave the system in Standby controlat this stage.

10.12.5 Check Temperature Compensation (If Applicable)

1) Connect a resistance of 100 between terminals 116 and 117. Terminals 116and 118 should be connected together. Use the HMI ('Modules' button) toenable the OEL Temp Compensation module on the control card. Check thatthe OE Limiter Ambient Temperature Compensation is set according to the



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10.13.2 Check The Over Flux Monitor

1) Run in Auto, at 100% volts and, use the HMI to set the OverFlux Monitor SetPoint to 1.1 pu (Maintenance Presets).

2) Whilst running at rated speed, note the Over Flux Monitor Trip Point whichshould be 10% above VT Nominal (any slight difference could be due tofrequency not being exactly at nominal). Increase the line voltage to justabove the monitor trip point (temporarily disable Over Flux Limiter on the A30-CON if necessary) and note that the Over Flux Monitor Timer begins toincrease slowly. Confirm that the monitor trips to standby when the timerreaches 100% and that LED 7 on the A30-MON is turned on.

3) Reduce the line voltage to nominal; reset the Over Flux Monitor, check for nullbalance and transfer to Main.

4) Set the Over Volts and Over Flux Monitor Set Points and Delays (MaintenancePresets) to the levels given in the QC.48 document.

10.14 Set/Check The Under Voltage Monitor Level

1) Use the HMI to disable the Under Volts Monitor ('Modules' button). Set the Under VoltsMonitor Set Point 5% below the VT Nominal and the Under Volts Monitor Delay to 30%

second (Maintenance Presets).2) Lower the excitation in Main to 10% below the nominal voltage.

Use the HMI to enable the Under Volts Monitor. Check that LED 6 on the A30-MON cardis illuminated and the AVR is tripped to Standby after approximately 6 seconds.

3) Raise the line voltage to the nominal level in Standby and then reset the Under VoltsMonitor using the reset pushbutton on the A30-MON card. Check for null balance andtransfer from `Standby' to `Main'.

4) Set the Under Volts Set Point and Delay (Maintenance Presets) to the level given in the



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9) Depending upon the external reactance Xe and the configuration of the system, theamount of QCC should be reduced to a level that gives stable control of VArs as the AVR

datum is adjusted. Typically the QCC is set at 4% for Xe = 0.

10.16 Check Under Excitation Limiter

1) Run the machine in parallel with the grid system under Main AVR control at zero or lightload.

Check that the Under Excitation Limiter Software is enabled. Check that the LeadingISin Limit and the external reactance (Xe) are set as shown in the QC.48 document.

(Maintenance Presets).2) Slowly reduce the excitation observing the status of the UELimiter on the HMI. (Note: the

Limit@0MW indicates only when running at leading PF)

Check that the Leading VArs are limited to a level close to the set point and that theexcitation is reasonably stable. UE Limiter P, I D gains can be adjusted if necessary(Maintenance Presets).

Unless Xe is zero, the limiting level of VArs will reduce as power increases. Check that

LED 4 on the control card is on when limiting.3) Slowly raise the excitation to come off the under excitation limit.4) If possible check the characteristic of the under excitation limiter by measuring the

operating points of different load levels and plotting them on the capability diagram.5) The transient response of the UE Limiter can be observed using the VRef Step Down

facility ('Tests' button) refer to Section 14.4 for details of this and UEL stabilisingadjustment.

10.17 Check Under Excitation Monitor



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5) Adjust the PF Reference using the PF/VAr Raise/Lower panel switches to the requiredsetting (the set point is shown on the HMI) and check that the PF is controlled to the

required level and is stable over the full range of power.

The rate at which the PF Reference is changed may be set in the Maintenance Presets.

If it is necessary, the PF Gain and PF Slug may be used to optimise the response of thePF Controller.

6) If it is required to adjust the PF Reference via the HMI, the Panel/HMI switch should beset to HMI, and the PF Reference is then adjusted using the Operator Presets. In thiscase it is necessary to select whether the required PF Ref is Leading or Lagging using the

'Modes' button on the HMI.

10.19 Check VAr Control (If Applicable)

1) Initially disable the PF/VAr/VAr shed software ('Modules' button) Confirm s/w is disabledon the HMI. Check on the HMI that the Panel/HMI switch (local/remote) indicates Panel,and that the Mode Selection Method indicates Switches.Note: The Trend Data may be used to display VArs (in terms of the sensing signalsprovided to the AVR) and is a useful means of displaying the response of the VAr control

and VAr shed facilities.2) Run the set in parallel with the grid on Main AVR control at 10% VArs lagging. Check that

VAr control is selected and that LED 8 on the A30-CON card is on.3) Use the Panel Switches to set the VAr Ref to zero using the HMI to observe the VAr Ref

and the status of the panel switches.4) Enable the PF/VAr/VAr shed software ('Modules' button) and check that the VArs are

reduced to zero and remain stable.5) Adjust the VAr Reference to the required setting using the PF/VAr Raise/Lower panel

switches (the set point is shown on the HMI) and check that VArs are controlled to the



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4) Check that the VArs can be easily adjusted by changing the voltage setting point of theStandby regulator.

Slowly load the generator to 10% of the generator MW capacity.5) Check that the null balance meter is positioned at the centre. Transfer from `Standby' to

`Main'.6) Slowly reduce the VArs and the MWs on the generator. Open the grid breaker.

10.22 Static Interrogation

If the PMG supply is not available because the machine is not running, it is possible to use an

alternative ac supply to power the electronics. This will allow interrogation of the AVR by usingthe PC and HMI software.

Follow the procedure below:1) Ensure that the Main Channel Supply switch (SW1) on the fixed front panel is in the off

position.2) Temporarily remove and insulate the wires in terminals 29 and 30 of Plug 6 at the rear of

the unit. (These are the wires which route the PMG supply to the Utility, Control andMonitor cards).

3) Set the links LK1 to LK6 on the Auxiliaries Board to suit the available supply as shownbelow. (Supply can be 50 or 60Hz)

Table 2: Auxiliaries Board Link Settings

Auxiliaries BoardVoltage Links Selected

Nominal Voltage Rating66-480Hz

Nominal Voltage Ratingat 50/60Hz

1, 3, 6 220 - 330V 250 10%



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11 USING THE WINDOWS HMI COMMISSIONING SOFTWARE

The A30-CON and A30-MON cards are setup using a PC connected using the supplied serialcommissioning cable. The commissioning software, (referred to as the Human Machine Interface orHMI application), is supplied on a CD.



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On startup, the HMI will request the name and location of the event log file

Documents

HB959202000 A30 Excitation Controller.pdf