Ex2 k hardware tab 3

GE Power Systems

Revision Date: 02/10/2000Revision Date: 02/10/2000 Property of Power Systems University- Proprietary Information for Training Purposes Only!Property of Power Systems University- Proprietary Information for Training Purposes Only!

EX2000 Hardware Details

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Objectives

• Identify all of the system components associated with “your” exciter.

• Be able to locate each component in the GE excitation elementary drawings.

• Describe the function of each system component.

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EX2000 Hot Back Up System

• Hot B/U system is used for redundant applications.

• Usually 2 separate power conversion sections (PCM) that make DC, one is sent to the field, the other to a 200 ohm resistor.

• 3 independent computers. 2 computers are used for control of the bridges. The other for protection.

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EX2000 Hot Back Up System

• The unit is broken up into 2 identical sections: Primary and B/U.

• Each section is broken down into Cabinet Hardware and a Control Core.

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EX2000 Hardware

• The EX2000 Cabinet Hardware consists of:– Manual AC

Disconnect

– DC Disconnect

– DC Shunt

– Control Power Supply

– Power Conversion Section

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Excitation Transformer (PPT)

• Power to the bridges is supplied by an external Excitation Transformer (aka PPT).

• The PPT steps down 4160 vac into either 380/480 vac.

• This low voltage AC source is converted to DC by the SCR’s.

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Manual AC Disconnect

• Disconnects the filtered secondary of the excitation transformer to either the Primary or Backup bridges.

• Molded Case 3-phase, non-automatic, panel mounted switch.

• Normally Rated at 600 vac @ 2500 amps (UL).

• No-Load Disconnect device!

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GE Power Systems


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• Functions to convert AC power in DC.

• 6 SCR’s fire at different angles to achieve the desired DC output.

• 12 identical fuses (2/SCR) protect the SCR’s and ensure equal current division.

Power Conversion Module (PCM)

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• 6 Leg Reactors limit current changes through the SCR’s.

• R/C Snubber circuits protect the SCR’s after conduction has stopped.

• Thermal Detectors are mounted on the SCR heat sinks.

• Alarm at 170 oF

• Trip at 190 oF


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Power Conversion Module

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Blowers

• (3) motor driven fans provide cooling circulation air through the SCR heat sink.

• Power for the motors can come from customer preferred AC or the PPT secondary and stepped down to either 440 or 120 vac.

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GE Power Systems


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DC Current Shunt

• Provides the bridge output current feedback signal to the control core.

• The mV output signal is inputted to a differential amplifier on the DCFB Board.

• Located on the Positive (+) DC bus bar in series with the field.

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DC Current Shunt

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DC Disconnect (MD A and B)

• (MD) Magnetic Disconnect

• Connects the output of the PCM to the field.

• Software Controlled

• Contacts Close at 95% Speed

• Open at 93% Speed

• Can not be Manually Operated

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Control Power Supplies

• Dual Power Supply with 125 vdc and 120 vac customer preferred inputs.

• (1) Power supply per Control Core.

• The power supply provide 120 vdc and 24 vdc power to relays and individual computer boards.

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Control Core

• Consists of 4 printed wiring boards that work as the “BRAIN” for the exciter.

• Calculates the proper amount of excitation and delivers the gate firing signals to the SCR’s.

• The control core will calculate:– Generator Volts,

– Generator Amps,

– MW’s,

– MVARS and pf

– Generator Operating Point

– Protection Alarm and Trip settings

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• This control card is the main processor board.

• Provides SCR circuit control.

• Keypad for Local Operation

• Regulator functions including:– Automatic

– Manual

– Protection

• Communication on the Local Area Network.

LAN Drive Communication Card (SLDCC)

SLDCC

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SLDCC

LAN Drive Communication Card (SLDCC)

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• Receives 3 of the major Feedback Signals:– DC Field Volts

– DC Field Current

– Excitation Secondary

• Receives attenuated signals from the SHVI board.

DC Feedback Board (DCFB)

DCFB

SLDCC

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DCFB

DC Feedback Board (DCFB)

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SCR High Voltage Interface (SHVI)

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• Provides attenuation of:– 3-phase Bridge Voltage

– DC Field Voltage

– DC Field Current

SCR High Voltage Interface (SHVI)

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SHVI Board

DC1PLPositive mV signal

from DC shunt

DC2PLNegative mV signal

from DC shunt

VCOAnalog to Digital

Converters

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SHVI BoardL1, L2, L3

AC Bridge Feedback (Phases A,B, and C)

P1, P2DC Bridge Feedback

(P1 is Positive, P2 Negative).

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• Processes analog signals and converts them to digital signals.

• Transducer algorithms are used to calculate system information.

• EX2000 simulator software is located here.

Microprocessor Application Card (TCCB)

DCFB

SLDCC

TCCB

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Microprocessor Application Card (TCCB)

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• Provides the interface between the SCR’s and the Control Core (via the DCFB Board).

Power Connect Card (PCCA)

DCFB

SLDCC

TCCB

PCCA

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Power Connect Card (PCCA)

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PTCT Board • Isolates and scales the Terminal

Voltage and Current feedback signals from the generator PT’s and CT’s.

• Isolated the Control Core from the PT’s and CT’s. Ea. Core has 1 PTCT board.

• Isolation switches (PTSW and CTSW) are provided for testing and maintenance.

• The LCI inputs the EX2000 reference signal on this board

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PTCT Board

• The output of the PTCT Board is sent to the TCCB Board.

• The TCCB Board will process and convert the signals from analog to digital and use them to calculate generator volts, current, MW’s, MVARS, etc.

• If the PTCT Board fails, the exciter auto regulator would not work because the generator terminal volts feedback signal is lost.

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Relay Terminal Boards (RTB)

• These boards contain relays which can be software driven via the LTB pilot relays or externally driven

• One application is to initiate a trip of the Generator Lockout Relay

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Revision Date: 02/10/2000Revision Date: 02/10/2000 Property of Power Systems UniversityProperty of Power Systems University-- Proprietary Information for Training Purposes Only!Proprietary Information for Training Purposes Only!

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LAN Terminal Board (LTB)

• This terminal board provides:– 8 Contact Inputs– 14 Contact Outputs

• Configurable for specific jobs.

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• These boards contain:– RS-232 computer

communication port to allow communication between that particular core and a computer.

– Configuring hardware jumpers on the board can customize the relays.

NTB/3TB Terminal Board

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ACRNet Communication Board (ACNA)

• These devices have two coaxial cable connections that allow the exciter and protection cores to connect and also connect the OC 2000.

• Communication within the EX2000 and UC/0C2000 is ARCNET or a Token ring network

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Mark V

• Provides the reference or “setpoint” parameters to the EX2000

• MK V communicates through the UC2000 to the EX2000.

• MKV communicates on the LAN via a coaxial (ARCNET) cable

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OC 2000• Operator Control 2000 - Sequencing - Operator Interface

• Digital Meters• Push-Buttons• Status Lights• Diagnostic Displays

- Hard I / O• Contact I / O• Analog I / O

• Mark V Interface

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UC/OC 2000

UC 2000

OC 2000

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Protection Core

• Almost exactly the same computer as what is in the Primary and Backup Cores.

• Receives the same setpoint and feedback signals as Primary and Backup.

• Does not fire SCR’s.

• Responsible for the “Transfer Function”.

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• Provides a current path path to collapse the generator field when MDA/B open.

• During an abrupt trip, MDA are opened immediately and an SCR associated with the module is fired to provide at path for current flow through a discharge inductor and dissipates the stored energy of the field.

De-Excitation Module

*De-excitation Module shown is configured for EX2100.

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• If the De-Excitation circuit is active and the exciter has not been issued a STOP command, a fault (FLT.715) occurs. If the generator is On-Line, the fault will issue a trip request.


*De-excitation Module shown is configured for EX2100.

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DC Shunt

M DB

M DA

Fie

ld

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• Protects the generator journal bearings.

• Limits shaft to ground voltages to less than 7 vdc.

• If the voltages are high enough, the voltage can cause an arc from the shaft through the oil and into the journal bearing babbit.

• The SVS is a low pass filter that conducts the high frequency components of the induced voltages to ground.

Shaft Voltage Suppressor (SVS)

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Shaft Voltage Suppressor (SVS)

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• Detects a single field ground. and will either

• Creates an Alarm or Trip:– > 5000 ohms -No Alarm, No

Trip

– > 2000 ohms but < 5000 ohms - Alarm

– < 2000 ohms - Trip

Field Ground Detector

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Field Ground Detector

m ax (+)

(-)

A B C

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Ex2 k hardware tab 3