GE Industrial Systems
GE Industrial Systems
GEH-6375A GEH-6375AEX2000
EX2000
PWM Digital Regulator
PWM Digital Regulator
User's Guide
User's Guide
GE Industrial Systems
GE Industrial Systems
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EX2000
EX2000
PWM Digital Regulator
PWM Digital Regulator
User's Guide
User's Guide
© 2000 General Electric Company, USA.
All rights reserved.
Printed in the United States of America.
These instructions do not purport to cover all details or variations in equipment, nor to
provide every possible contingency to be met during installation, operation, and
maintenance. If further information is desired or if particular problems arise that are not
covered sufficiently for the purchaser’s purpose, the matter should be referred to GE
Industrial Systems, Salem, Virginia, USA.
This document contains proprietary information of General Electric Company, USA and is
furnished to its customer solely to assist that customer in the installation, testing,
operation, and/or maintenance of the equipment described. This document shall not be
reproduced in whole or in part nor shall its contents be disclosed to any third party without
the written approval of GE Industrial Systems.
Document Identification: GEH-6375, updated release
Windows NT is a registered trademark of the Miscrosoft Corporation.
Windows is a registered trademark of the Microsfot Corporation.
GEH-6375A User's Guide Safety Symbol Legend •• • • a
Safety Symbol Legend
Indicates a procedure, condition, or statement that, if not strictly observed, could result in personal injury or death.
Indicates a procedure, condition, or statement that, if not strictly observed, could result in damage to or destruction of equipment.
b • •• • Safety Symbol Legend EX2000, PWM Digital Regulator GEH-6375A
This equipment contains a potential hazard of electric shock or burn. Only personnel who are adequately trained and thoroughly familiar with the equipment and the instructions should install, operate, or maintain this equipment.
Isolation of test equipment from the equipment under test presents potential electrical hazards. If the test equipment cannot be grounded to the equipment under test, the test equipment’s case must be shielded to prevent contact by personnel.
To minimize hazard of electrical shock or burn, approved grounding practices and procedures must be strictly followed.
To prevent personal injury or equipment damage caused by equipment malfunction, only adequately trained personnel should modify any programmable machine.
GEH-6375A User'sGuide Contents •• • • i
Contents
Chapter
1
Overview
1-1
Introduction... 1-1 System Overview... 1-2 Product Overview... 1-3 Hardware Design ... 1-3 Power converter module... 1-5 Software Design ... 1-6 Human-Machine Interface (HMI)... 1-8Chapter 2 Hardware System Description
2-1
Introduction... 2-1 Packaging... 2-2 Environmental ... 2-2 Enclosure... 2-2 Ratings ... 2-3 Input Ratings ... 2-3 Output Current Rating... 2-4 Voltage Control Range... 2-4 Power Profile Rating... 2-4 Power Converter Hardware... 2-5 Ac and Dc Input Devices... 2-6 Dc Link and Dynamic Discharge... 2-6 IGBT And IAXS Devices... 2-6 Output Contactor MDA... 2-7 Output Shunt SHA... 2-7 Control Electronics Module ... 2-7 TCCB (DS200TCCB) ... 2-8 PSCD (IS200PSCD) ... 2-8 GDDD (IS200GDDD) ... 2-8 PTCT (DS200PTCT) ... 2-8 NTB/3TB (531X305NTB) ... 2-9 LTB (531X307LTB)... 2-9 RTBA (DS200RTBA)... 2-9 ACNA (DS200ACNA) ... 2-9 Inputs and Outputs... 2-9 Generator Inputs ... 2-9 4-20 mA Inputs...2-10 Generator Line Breaker Status...2-10 Generator Lock-Out Trip...2-10 Additional I/O...2-11
ii • •• • Contents EX2000, PWM Regulator GEH-6375A
Chapter 3 Software System
Overview
3-1
Introduction... 3-1 Configuration Tools... 3-2 Programmer Module... 3-2 Software Design ... 3-2 Standard Functions ... 3-3 Automatic Voltage Regulator (AVR) Ramp... 3-3 Automatic Voltage Regulator Setpoint ... 3-3 Automatic Voltage Regulator... 3-3 Field Regulator (FVR) Ramp ... 3-3 Field Regulator ... 3-3 Under Excitation Limiter (UEL)... 3-4 Over Excitation Limiter (OEL)... 3-4 Firing Block... 3-4
Chapter 4 Software Configuration and Scaling
4-1
Introduction... 4-1 Configuration and Scaling Example ... 4-2
Example Generator, Exciter, and Regulator ... 4-3 General Configuration ... 4-4 Feedback Scaling... 4-6 Generator Feedback ... 4-6 Bridge Voltage Feedback ... 4-7 Bridge Current Feedback... 4-8 Feedback Offsets... 4-8 Instantaneous Overcurrent Trip ... 4-9 Regulator Scaling ... 4-9
Automatic Voltage Regulating System ... 4-9 Under Excitation Limiter (UEL)...4-13 Reactive Current Compensator (RCC)...4-16 VAR/Power Factor Control...4-17 Field Regulator (FVR) ...4-18 Field Current Regulator (FCR)...4-20 Optional Functions Scaling and Configuration...4-23 Transducer Outputs...4-23 Ground Detector and Diode Fault Monitor...4-24 Field Thermal Model ...4-25
Chapter
5
Startup
Checks
5-1
Introduction... 5-1 Prestart Checks ... 5-2 Energization and Simulator Control Checks... 5-2 Pre-start Power Checks ... 5-4 Initial Roll Offline Checks ... 5-6 Online Checks ... 5-7 Operator Interface... 5-8 Units with Innovation Series Controller... 5-8 Units with Discrete Switches and Meters... 5-8
GEH-6375A User'sGuide Contents •• • • iii
Chapter 6 Simulator Scaling and Operation
6-1
Introduction... 6-1 Simulator... 6-1 Simulator Scaling... 6-2 Operation... 6-4
Glossary of Terms
Index
GEH-6375A User's Guide Chapter 1 Overview • •• • 1-1
Chapter 1 Overview
Introduction
This manual describes the EX2000 Pulse Width Modulated (PWM) digital regulator for brushless generator excitation systems. This is a microprocessor controlled power converter that produces controlled dc output for rotating exciter, brushless generator applications.
This manual is intended to a ssist applications and maintenance personnel in
understanding the equipment hardware and software. It also provides initial startup information.
The manual is organized as follows:
Chapter 1 briefly defines the EX2000 PWM regulator with an overview of the hardware and software design. Includes references to other manuals and documents, one-lines and connection diagrams. Its purpose is to present a general product overview for the reader as follows:
Section Page
System Overview ... 1-2 Product Overview... 1-3 Hardware Design... 1-3 Power Converter Module... 1-5 Software Design... 1-6 Human-Machine Interface (HMI) ... 1-8 Chapter 2 Hardware System Description, contains specific information on system hardware design and purpose, ratings, I/O definition.
Chapter 3 Software System Overview, contains specific information on software tools, structure, functions, and one-line representations.
Chapter 4 Software Configuration and Scaling, gives examples of the scaling for specific parameters in a generic brushless regulator generator application.
Chapter 5 Startup Checks, contains pre-start, startup, and on-line adjustments required during the commissioning of the PWM regulator for a brushless excitation system.
Chapter 6 Simulator Scaling and Operation gives example simulator scaling and operation instructions for a typical brushless regulator generator application.
1-2
1-2 ••• • • • • • CChhaapptteer r 1 1 OOvveerrvviieeww EEXX22000000, , PPWWM M DDiiggiittaal l RReegguullaattoor r GGEEHH--66337755AA
System Overview
System Overview
A second pow
A second power source is alsoer source is also possible from a dc
possible from a dc batterybattery source.
source.
The PWM regulator controls the ac t
The PWM regulator controls the ac t erminal voltage and/or the reactive volt ampereserminal voltage and/or the reactive volt amperes of the generator by controlling the
of the generator by controlling the field of the rotating brushless exciter. Figure 1-1field of the rotating brushless exciter. Figure 1-1 shows a typical one-line system of a Permanent Magnet Generator (PMG) fed shows a typical one-line system of a Permanent Magnet Generator (PMG) fed brushless generato
brushless generator application. Por application. Power for the wer for the regulator is normally regulator is normally supplied from asupplied from a PMG driven directly by the main generator field. This can be a single phase or PMG driven directly by the main generator field. This can be a single phase or 3- phase PMG. A
phase PMG. An alternative metn alternative method is to obtain excithod is to obtain excitation regulator poation regulator power from awer from a Power Potential Transfo
Power Potential Transformer (PPT) supplied from an auxiliary bus. This rmer (PPT) supplied from an auxiliary bus. This can also becan also be a single or 3-phase supply. The PPT is required to ensure an ungrounded input to the a single or 3-phase supply. The PPT is required to ensure an ungrounded input to the regulator.
regulator.
The control system contains both a
The control system contains both a generator terminal voltage regulator and angenerator terminal voltage regulator and an exciter field current regulator. These are known as
exciter field current regulator. These are known as the automatic or ac regulator andthe automatic or ac regulator and the manual or
the manual or dc regulator respectively.dc regulator respectively. When operating under control of th
When operating under control of th e dc regulator, a constant exciter field current ise dc regulator, a constant exciter field current is maintained, regardless of the operati
maintained, regardless of the operating conditions on the generator terminals. ng conditions on the generator terminals. WhenWhen operating under control of the ac
operating under control of the ac regulator, a constant generator terminal voltage isregulator, a constant generator terminal voltage is maintained under varying load conditions. If the gen
maintained under varying load conditions. If the gen erator is connected to a largeerator is connected to a large system through a low impedance tie, the
system through a low impedance tie, the generator cannot change the system voltagegenerator cannot change the system voltage appreciably. The ac regulator, with very small variations in t
appreciably. The ac regulator, with very small variations in t erminal voltage, theerminal voltage, thenn controls the reactive volt
controls the reactive volt amperes (Var)s.amperes (Var)s. If the generator is i
If the generator is i solated from a system, the ac regulator solated from a system, the ac regulator controls the terminalcontrols the terminal voltage and the
voltage and the Vars are determined by the load. Most systems operate in Vars are determined by the load. Most systems operate in a manner a manner that is between these two extremes. That is, both Vars and volts are controlled by the that is between these two extremes. That is, both Vars and volts are controlled by the ac regulator. Normal operation is with the ac r
ac regulator. Normal operation is with the ac r egulator in control, with an automaticegulator in control, with an automatic transfer to the dc regulator in
transfer to the dc regulator in the event of loss of potential the event of loss of potential transformer feetransformer feedback asdback as detected through Potential Transformer Failure (PTFD) or PT Undervoltage detected through Potential Transformer Failure (PTFD) or PT Undervoltage Detection (PTUV).
Detection (PTUV).
In the regulator, PT Failure Detection requires two sets of PT inputs. There is In the regulator, PT Failure Detection requires two sets of PT inputs. There is automatic tracking between the ac and
automatic tracking between the ac and dc regulators to ensure a dc regulators to ensure a bumpless transfebumpless transfer inr in either direction. A balance signal is available for di
either direction. A balance signal is available for di splay on the operator station or splay on the operator station or turbine control interface. A transfer between regulators can be initiated by the turbine control interface. A transfer between regulators can be initiated by the operator or, if supplied, by the PT failure detection algorithm. In addition to the operator or, if supplied, by the PT failure detection algorithm. In addition to the reference input to the ac
reference input to the ac regulator summing junction, a number of both regulator summing junction, a number of both standard andstandard and optional inputs are possible.
optional inputs are possible. The regulator includes a
The regulator includes a Local Area N
Local Area Network (Letwork (LAN)AN) and RS-232C interfaces for and RS-232C interfaces for external communication. external communication.
Besides the regulating
Besides the regulating functiofunctions, the ns, the excitatioexcitation sn system contains protective limiter ystem contains protective limiter functions, startup and shutdown functions, and operator interfaces that are
functions, startup and shutdown functions, and operator interfaces that are implemented in both h
implemented in both hardware and/or software.ardware and/or software.
The software is accessed via an RS-232C communication link using the GE Controls The software is accessed via an RS-232C communication link using the GE Controls Systems Toolbox (toolbox)
Systems Toolbox (toolbox). The . The toolbotoolbox is x is used to configure and maused to configure and ma intain regulatorsintain regulators and exciters. It is Windows
and exciters. It is Windows®®-based and consists of a collection of programs (tools)-based and consists of a collection of programs (tools) running under a command
G
GEEHH--66337755A A UUsseerr''s s GGuuiiddee CChhaapptteer r 1 1 OOvveerrvviieeww • • ••• • • • 1-31-3
Figure 1-1.
Figure 1-1. PMG Brushless PMG Brushless Exciter Overview Exciter Overview
Product Overview
Product Overview
Hardware Design
Hardware Design
Optional hardware devices Optional hardware devices are also available, such as are also available, such as 4-20 mA transducers, PPT, and 20 mA transducers, PPT, and Field Ground Det
Field Ground Detector Powector Power er supplies.
supplies.
The regulator hardware consists of a
The regulator hardware consists of a control core and a control core and a powepower converter section,r converter section, described in Chapter 2. The
described in Chapter 2. The controllercontroller includes printed wiring boards includes printed wiring boards containingcontaining programmable mic
programmable microprocessors wroprocessors with companion circuitith companion circuitry, including elecry, including electrically- trically-erasable programmable read-only memory (EEPROM) where
erasable programmable read-only memory (EEPROM) where the regulator’s the regulator’s systesystemm blockware pattern is
blockware pattern is stored. Tstored. Thehe power converterpower converter consists of input disconnects and consists of input disconnects and filters, a dc link
filters, a dc link with charge control, IGBT devicewith charge control, IGBT devices, output s, output contactor and shunt, andcontactor and shunt, and control
1-4
1-4 ••• • • • • • CChhaapptteer r 1 1 OOvveerrvviieeww EEXX22000000, , PPWWM M DDiiggiittaal l RReegguullaattoor r GGEEHH--66337755AA
Control Core (Regulator Module)
Control Core (Regulator Module)
Refer to figures
Refer to figures 2-3 and 2-42-3 and 2-4 in Chapter 2.
in Chapter 2.
The control core is mounted in two board racks on the outside of the core panel and The control core is mounted in two board racks on the outside of the core panel and is accessible while the regulator is operating. Also, behind the
is accessible while the regulator is operating. Also, behind the hinged outer door,hinged outer door, several Input/Output (I/O) boards are mounted. The control core consists of all these several Input/Output (I/O) boards are mounted. The control core consists of all these circuit boards interconnected by ribbon cables and harn
circuit boards interconnected by ribbon cables and harn esses, which keep wiring to aesses, which keep wiring to a minimum. Detailed hardware information including fuse and
minimum. Detailed hardware information including fuse and test point information,test point information, replacement instructio
replacement instructions and ns and board layouts are provided in the rboard layouts are provided in the r eferenced documentseferenced documents for each of the
for each of the followfollowing ing circuit boards.circuit boards.
Power Supply and Contactor Driver (PSCD)
Power Supply and Contactor Driver (PSCD) board creates internal power supplies board creates internal power supplies and redistributes the necessary power supply voltages for the
and redistributes the necessary power supply voltages for the other control coreother control core circuit boar
circuit boards. ds. An isolated 70 V An isolated 70 V dc supply is also produced and used for Ldc supply is also produced and used for LTB boardTB board inputs. The PSCD board also produces the contactor
inputs. The PSCD board also produces the contactor coil voltage for the MDA outputcoil voltage for the MDA output and charge control contactor (refer to GEI–100241).
and charge control contactor (refer to GEI–100241). Gate Driver and Dynamic Discharge (GDDD)
Gate Driver and Dynamic Discharge (GDDD) controls the gating of the IGBTs for controls the gating of the IGBTs for bridge output and D
bridge output and Dynamic Dischaynamic Discharge control. It arge control. It also isolates also isolates and scales dc outputnd scales dc output,, dc link voltage, shunt feedback and h
dc link voltage, shunt feedback and h eat sink temperature feedbacks (refer to GEI– eat sink temperature feedbacks (refer to GEI– 100240).
100240).
LAN Terminal Board (LTB)
LAN Terminal Board (LTB) provides an provides an interface beinterface between control devices andtween control devices and external devices such as contactors, relays, indicators, lights, pushbuttons and external devices such as contactors, relays, indicators, lights, pushbuttons and interlocks (refer to GEI
interlocks (refer to GEI−−100022).100022).
Microprocesso
Microprocessor r ApplicatioApplication Board n Board (TCCB)(TCCB) contains software transducering contains software transducering algorithms that mathematically manipula
algorithms that mathematically manipulate the inputs te the inputs from the isolation and scalingfrom the isolation and scaling printed wiring bo
printed wiring boards. These inputs ards. These inputs are analog feare analog feedback signals from tedback signals from the current andhe current and voltage transformers, which monitor generator output and line voltage, and from the voltage transformers, which monitor generator output and line voltage, and from the bridge ac input a
bridge ac input and dc output vond dc output voltages and shunt feltages and shunt feedbacks (refer to Gedbacks (refer to GEIEI−−100163).100163).
I/O Terminal Board
I/O Terminal Board (NTB/3TB)(NTB/3TB) includes an RS-232C communication port for includes an RS-232C communication port for connecting to a
connecting to a personal computer (PC). The optional field ground detector inputspersonal computer (PC). The optional field ground detector inputs are connected to the
are connected to the NTB board (refer to GEI–100020).NTB board (refer to GEI–100020). Drive Control and LAN Control Board (LDCC)
Drive Control and LAN Control Board (LDCC) controls LAN communication controls LAN communication and permits operator access and
and permits operator access and control via the Programmer keypad. It also containscontrol via the Programmer keypad. It also contains the drive control
the drive control microprocessomicroprocessor r which monitors start/stop sequencing, alarms, tripswhich monitors start/stop sequencing, alarms, trips and outer loop regulators and
and outer loop regulators and motor control microprocesmotor control microprocessors which monitors thesors which monitors the field voltage and current regulators, gating and overcurrent protection (refer to GEI– field voltage and current regulators, gating and overcurrent protection (refer to GEI– 100216, for reprogramming the LDCC board refer to GEI
100216, for reprogramming the LDCC board refer to GEI−−100217).100217).
Relay Terminal Board (RTBA)
Relay Terminal Board (RTBA) provides seven output relays with form C provides seven output relays with form C contactscontacts available for customer use which can be driven from a remote input or directly from available for customer use which can be driven from a remote input or directly from the relays on th
the relays on th e LTB board (refer GEI–100167).e LTB board (refer GEI–100167). ARCNET Link (ACNA)
ARCNET Link (ACNA) board provides the board provides the connection point for the ARCNETconnection point for the ARCNET LAN communications.
GEH-6375A User's Guide Chapter 1 Overview • •• • 1-5
Figure 1-2. EX2000 Brushless Unit
Power Converter Module
The power conversion section consists of an input section, a dc link, and the converter output section. The input section is a 3-phase diode bridge with input filters. The range of the ac input is from 90 V rms up to 275 V rms. Frequency inputs range as high as a nominal 360 Hz. It can be a single phase or three phase input from a PMG, auxiliary bus or generator terminal fed. An input PPT is not required for the PMG input. A PPT is required for an auxiliary bus or generator terminal feed. An optional voltage doubling feature is available for units requiring higher forcing capability.
This circuit is normally powered from the GDDD
board but may be powered through the dynamic discharge power source resistor RDS if control power is lost.
An optional backup source from nominal 125 or 250 V dc batteries is filtered, diode isolated and combined with the three-phase diode bridge output. These sources charge the power capacitors through a charge control resistor, RCH, which forms the dc link portion of the power converter module. The dc link is the unregulated source voltage for the control core power supplies and the output power through th e IGBTs. A coarse control of the voltage level of the dc link is provided by the dynamic discharge circuit. This circuit will dissipate excess power from the dc link (possible due to a regeneration effect from the field of the r otating exciter) through the dynamic discharge resistor, RDD.
The converter output section takes the dc link source voltage and pulse width modulates it through the IGBT devices. The output voltage i s determined by the following formula:
Voutput = Vinput * (time on/(time on + time off))
For more information refer to Chapter 5, Figure 5-1.
where Vinput is the dc link voltage, time-on is the conduction time of the IGBT devices and time-off is the n on-conduction time of the IGBTs. The chopping frequency of the IGBTs is a pproximately 1000 Hz.
This output is fed to the rotating exciter field as a regulated voltage or current. A single pole contact from the MDA contactor isolates the regulator from the field. An output shunt monitors the field current.
1-6 •• • • Chapter 1 Overview EX2000, PWM Digital Regulator GEH-6375A
Optional Hardware Modules
Scaling is provided in the PWM software.
There are a limited number of structured options available with the PWM regulator. Up to four 4-20 mA output transducers are available for customer use. They ar e driven from D/A converters located on the NTB board, and are non-adjustable devices.
A 50/60 Hz, 25 kVA Power Potential Transformer (PPT) is available for units that are connected to an auxiliary bus or generator output termina ls. This PPT may or may not be supplied inside the regulator enclosure. Power to the primary should be fused per the application notes found in the control elementary supplied with the equipment. This transformer is sized to supply rated excitation requirements continuously and still be capable of operation at ceiling excitation for a short time. An optional Field Ground Detector Power supply may be supplied for some systems. This power supply provides 24 V control power to the Field monitor unit mounted in the generator exciter housing. A 120 V ac feed is required to power this supply.
Software Design
The regulator application software consists of modules (blocks) combined to create the required system functionality. Block definitions and configuration parameters are stored in read-only memory (ROM), while variables are stored in random-access memory (RAM). Microprocessors execute the code.
Diagnostic software is transparent to the user. A programmer module with a digital display and keypad allows an operator to request parameter values and self-checks.
Software
The exciter application emulates traditional analog controls. It uses an open architecture system, which uses a library of existing software blocks. The blocks individually perform specific functions, such as logical AND gates, proportional integral (PI) regulators, function generators, and signal level detectors.
These blocks are tied together in a pattern to implement complex control functions. For example, a control function such as the under-excitation limit (UEL) is included as an ac r egulator input by setting software jumpers in EEPROM. The relevant
blockware is enabled by pointing the block inputs to RAM locations where the inputs reside (the UEL requires megawatts, kilovolts and megavars). The UEL output is then pointed to an input of the ac regulator summing junction. The software blocks are sequentially implemented by the block interpreter in an order and execution rate defined in the toolbox.
The blockware can be interrogated while running by using the toolbox. The dynamically changing I/O of each block can be observed in operation. This technique is similar to tracing an analog signal by using a voltmeter.
GEH-6375A User's Guide Chapter 1 Overview • •• • 1-7
AC and DC Regulators
The power system stabilizer (PSS) is an optional function.
The ac or automatic regulator and, dc or manual regulator are software functions again emulating traditional analog controls. The ac regulator reference is from a static counter and is compared t o the generator terminal voltage feedback to create an error signal. In addition to the reference signal input to the ac regulator summing junction, the following inputs can be used to modify the regulator action.
Alternatively it can be used to provide line drop
compensation.
Reactive Current Compensation (RCC): The generator voltage is allowed to vary in order to improve reactive volt amp (VA) sharing between generators connected in parallel. Generator voltage decreases as overexcited reactive current increases, and
increases as underexcited r eactive current decreases.
Under-excitation Limit (UEL): Under-excited Vars must be limited to prevent heating of the generator iron core and to ensure dynamic stability of the turbine generator. This is done by an under-excitation limiter that takes over when a specified limit curve is reached and prevents operation below this limit.
V/Hz: The ratio of generator voltage to frequency (V/Hz) must be limited. This prevents overfluxing the generator and/or line-connected transformers caused by
overvoltage operation or under-frequency operation, or a combination of the two. Power System Stabilizer (PSS): The introduction of high g ain, high initial response exciters can cause dynamic stability problems in power systems. The advantage of these exciters is to provide improved transient stability, but this is achieved at the cost of reduced dynamic stability and sustained low frequency oscillations. The PSS is an optional
function.
The PSS is fed with a synthesized speed signal based on the integral of accelerating power. This indicates the rotor deviation from synchronous speed. This signal is
conditioned and fed into th e summing junction of the continuously acting ac
regulator so that under deviations in machine speed or load, excitation is r egulated as a composite function of voltage and unit speed. The stabilizer therefore produces a damping torque on the generator rotor and consequently increases dynamic stability. Over-excitation Limiter (OEL): It is necessary to limit generator excitation current off-line to prevent overfluxing the generator and connected transformers. Online, it must be limited to prevent field thermal damage. The limiting action is performed by the excitation current regulator. The current regulator takes control of bridge gating if the regulator (automatic or manual) calls for exciter field excitation current in excess of a predetermined pick-up level.
The dc or manual regulator is configured as a field current regulator using shunt feedback and comparing it to the manual regulator static adjust reference. It will maintain a constant exciter field current based on the setpoint adjuster. The online and offline field current regulators are low value gate selected with the inner loop regulator output to select the appropriate firing level for the IGBT bridge.
Scaling
It is necessary to scale the software in each exciter for application with a particular generator. The regulators use normalized values of counts to represent one per unit (1 pu). Typically 1 pu equals either 5000 or 20000 counts. This means that the feedback value for a particular variable, such as dc link voltage (VDCLINK = 1 p u) or bridge current (AFFL = 1 pu), must be normalized by using a multiplier to equal the prerequisite value of counts when it is at 1 pu. See Chapter 4 for more details.
1-8 •• • • Chapter 1 Overview EX2000, PWM Digital Regulator GEH-6375A
Faults
Refer to GEI − 100242 for fault
codes, interpretation, and troubleshooting.
The EX2000 exciter has a sophisticated self-diagnostic capability. If a problem occurs, a fault code flashes in the programmer display showing a fault name and number. The fault number also appears on the display on the LDCC in coded form.
Simulator
Located within the core software is a sophisticated system simulation program that models the exciter and gen erator behavior. The simulator is activated via a software jumper in EEPROM.
The simulator physically operates the field contactors when a start signal is issued to the exciter. If dc link voltage is present, current may flow in the exciter field
.
This tool is useful for training, startup, and calibration checkout.
Signals representing the field and the generator feedbacks are simulated in the microprocessor application board (TCCB) and fed to the transducering algorithms, in place of the real feedbacks. Once the exciter is scaled for a particular generator, the simulator uses that scaling. For example, after a successful startup sequence is performed in simulator mode, the operator interface will displays the exciter voltage
and current and generator voltage applicable to th at particular unit.
Note Scaling and operation of the simulator is discussed in Chapter 6.
Human-Machine Interface (HMI)
Refer to the control
elementary supplied with the equipment for further information.
The PWM has a HMI datalink with the turbine controller over the Status_S page for regulator information. Optional interfaces include, discrete switches and meters, direct DCS control through an Innovation Series Controller, or some other device.
GEH-6375A User's Guide Chapter 2 Hardware System Description • •• • 2-1
Chapter 2 Hardware System Description
Introduction
This chapter describes the EX2000 PWM regulator hardware structure, and overall operation. When reading these descriptions, refer to Figure 1-2, the specific unit elementary, and the excitation layout diagrams provided with the equipment.
Section Page Packaging ... 2-2 Environmental... 2-2 Enclosure ... 2-2 Ratings ... 2-3 Input Ratings... 2-3 Output Current Rating ... 2-4 Voltage Control Range... 2-4 Power Profile Rating ... 2-4 Power Converter Hardware ... 2-5 Ac and Dc Input Devices... 2-6 Dc Link and Dynamic Discharge ... 2-6 IGBT And IAXS Devices ... 2-6 Output Contactor MDA... 2-7 Output Shunt SHA ... 2-7 Control Electronics Module... 2-7 TCCB (DS200TCCB) ... 2-8 PSCD (IS200PSCD)... 2-8 GDDD (IS200GDDD)... 2-8 PTCT (DS200PTCT)... 2-8 NTB/3TB (531X305NTB)... 2-9 LTB (531X307LTB) ... 2-9 RTBA (DS200RTBA) ... 2-9 ACNA (DS200ACNA)... 2-9 Inputs and Outputs ... 2-9 Generator Inputs... 2-9 4-20 mA Inputs ...2-10 Generator Line Breaker Status...2-10 Generator Lock-Out Trip...2-10 Additional I/O...2-11
2-2 •• • • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
Packaging
GEI-100228 provides information on Receiving, Storing, and Warranty Instructions for DIRECTO-MATIC® 2000 Equipment. This document should be consulted upon
receipt of the regulator.
Each regulator will withstand the following environmental conditions without damage or degradation of performance.
Environmental
Temperature requirements for the regulator should be maintained within the limits in GEI−100228 during transport and handling. Once installed, the operational limits of
an ambient temperature of 0 t o +45°C, outside of the convection cooled cabinet,
should be maintained. It is expected that the hottest board entry temperature will be approximately 60°C allowing the use of 70°C parts. Maintain 5 to 95% relative humidity with no external temperature or humidity excursions that would produce condensation.
The control equipment is also designed to withstand 10 ppb of the following contaminants: • reactive sulfur • reactive chlorine • hydrogen sulfide • sulfur dioxide • chlorine dioxide • sulfuric acid • hydrochloric acid • hydrogen chloride • ammonia
Enclosure
The standard offering is a NEMA 1 or IP20 equivalent, 90 inches high by 24 inches wide and 20 inches deep. An optional 36 inch wide enclosure is also available. In some instances, just the regulator panel without enclosure will be pr ovided. This panel measures approximately 63 inches high by 17 inches wide by 18.5 inches deep.
Other enclosure types are available.
The estimated weight is 1200 pounds with NEMA 1 24 inch enclosure, and 900 pounds without enclosure. The estimated watt losses are a maximum 200 watts for
GEH-6375A User's Guide Chapter 2 Hardware System Description • •• • 2-3
Ratings
Each regulator has a specific output limit rating based on the application of th e regulator and limited by the shunt chosen for the application. The following ratings information is the maximum output of the standard r egulator, using a 25 A shunt. For shunt ratings other than 25 A, the output current limitations will be reduced
proportionately. Name plate information should be used for accurate ratings.
Input Ratings
The ac input is the primary input power to the brushless regulator. The range of input ac is from 90 V rms up to 27 5 V rms. The ac input may be single or 3-phase. The input ac may be from a permanent magnet generator (PMG), customer supplied auxiliary bus, or bus fed from the generator. The ac source input to the regulator should have an impedance of 6 % nominal based on an estimated 20 A, 10 kVA source.
PMG Input
The voltage and frequency for PMG-based input will start from 0 and increase to rated as a function of generator speed. Rated input from the PMG system can be as high as 250 V ac rms / 36 0 Hz. Nominal voltages can be 100 V ac rms up to 250 V ac rms. With overspeed conditions, the maximum is 275 V ac rms / 440 Hz. Since the PMG is ungrounded and only used to source power to the brushless regulator, no input transformer is required. PMG systems on gas turbines will see extended
periods of time at < 50 % speed operation on startup. This is due to the purge cycle needed by the gas turbine. Since the PMG may be the only input power to the regulator, the control will initialize at ≤ 60 V ac rms (~50% speed).
Auxiliary Bus Input
Auxiliary bus-based systems require an input transformer to isolate the input to th e brushless regulator from the customer power system. This insures that the power
source to the brushless regulator is ungrounded. The transformer can be external to the enclosure that houses the brushless r egulator, but will generally be located in the panel. The secondary voltage can range from 90 V ac rms up to a max. 275 V ac rms. Nominal secondary voltages can be 100 V ac rms up to 250 V ac rms. Rated
frequency for the auxiliary bus-based systems can be 50 Hz or 60 ±10%.
Bus Feed from the Generator
Bus fed-based systems will require an input transformer to isolate the input to the brushless regulator from the power system. This also insures that the power source to
the brushless regulator is ungrounded. The transformer will be external to the
enclosure that houses the brushless regulator. The secondary voltage can range from 90 V ac rms up to a max. 275 V ac rms. Nominal secondary voltages can be 100 V ac rms up to 250 V ac rms. Rated frequency for the bus feed based systems can be 50 Hz or 60±10 %. If a bus fed system is applied on a black-start gas turbine, this input
may start at 20 % of rated speed, therefore, the voltage and frequency will start at 20 % of rated.
2-4 •• • • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
DC Input Power
The dc source input power is generally provided from a battery bus. This source is a back up to the primary ac input power source. It can be used as the primary input power for starting black-start turbine generators.
The nominal battery bus voltages are based on a 110/125/ 220 / 250 V dc. Therefore, the operating range for the dc input is from 80 V dc up to a max of 290 V dc.
Output Current Rating
The bridge is capable of delivering th e following absolute maximum output:
• 25 A dc continuously over the specified temperature range
• 40 A dc for 20 s once every 30 minutes after continuous operation at 25 A dc
over the specified temperature range.
The PWM bridge is monitored for excessive temperature by a heatsink sensor. Both alarm and trip signals are available.
Voltage Control Range
The PWM bridge is capable of t wo-quadrant operation (positive and negative output voltage, positive current). This allows operation near zero voltage. The PWM bridge has two active transistors and will operate in zero vector mode. This will allow the output voltage to be chopped in PWM fashion from +V dc to 0 for positive voltage commands and -V dc to 0 for negative voltage commands. The chopping frequency is approximately 1 kHz.
The IGBT bridge does not provide a low impedance path, which would provide rectification when gating is disabled. This prevents runaway conditions known to occur on brushless units having rotating diode failure. The four flyback diode structure provides this inherently.
Power Profile Rating
The output power profile is a function of line impedance, line current rating,
operating point (I dc and V dc), and capacitor current rating. Peak current is limited by IGBT rating. In general higher current output is available at lower output
voltages. Output current (I dc) can be higher than line current rating. The regulator shall be capable of matching the following power profile.
The continuous operating area is bounded by the minimum of the capacitor limit, line limit, 25 A dc, or maximum output curve and the x (V dc) and y (I dc) axis. The y-axis shows input line amps (rms), capacitor amps (rms), or output amps (dc) for a given output V dc and I dc. The curve labeled 25 shows rms capacitor current on the y-axis for a given V dc and 25 I dc.
GEH-6375A User's Guide Chapter 2 Hardware System Description • •• • 2-5 0 50 100 150 200 250 300 350 0 5 10 15 20 25 30 35 25 25 Adc
Output voltage (Volts dc)
Line and capacitor currents as functions of dc voltage and current
line limit 12.5 Arms cap limit 10 Arms
L i n e ( A r m s ) c , a p a c i t o r ( A r m s ) o , r o u t p u t ( A d c ) c u r r e n t IGBT limit 25Adc at 50 Vdc and 25 Adc capacitor current is 10 Arms at 200 Vdc and 25 Adc line current is 15 Arms maximum output
Figure 2-1. Typical Power Profile
The curve labeled 25 A dc shows rms line current on the y-axis for a given output V dc and 25 I dc.
Negative voltage operation is not shown.
The line limit curve corresponds to given V dc and I dc, which would result in rated line current. The cap limit curve corresponds to given V dc and I dc, which would result in rated capacitor current. The following graph illustrates the various limits.
Power Converter Hardware
For the following discussions, use elementary drawing 03A and the panel layout drawings (Figures 2-2 through 2-5) as references. The elementary drawing is typical for all applications. On a requisition basis, the output shunt (SHA), charge resistor (RCH), and dynamic discharge r esistor (RDS) may change. Also, various
combinations of the input source power may exist. A single phase PMG with battery backup is assumed.
2-6 •• • • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
Ac and Dc Input Devices
The ac input device DSWAC is a 3-phase, 600 V ac, 30A molded case industrial circuit breaker. For single-phase applications, the L1 and L3 connections should be used. The dc input device DSWDC is a two phase, 250 V dc, 30 A molded case industrial circuit breaker. These input devices are mounted at the top of the panel, easily accessible for operation as a disconnect during equipment maintenance or inspection.
All of these components are located at the top of the panel, behind the ac and dc
disconnects.
The ac input source is filtered by snubber RC networks and rectified by a 3-phase diode bridge (DM1, 2 and 3). The dc output of this bridge charges capacitors C1, C2, C3, and C4, forming the dc link. The dc supply is filtered through inductors (LPDC and LNDC) and battery capacitor C1F. It is then fed directly to the dc link through isolation diode DM4. MOV1 and MOV2 are provided for surge protection.
Dc Link and Dynamic Discharge
A charge control resistor (RCH) mounted on the heat sink assembly is provided to limits inrush current during powerup and capacitor charging. The second pole of the MDA contactor controls application or removal of the charge control resistor. The dc link provides the source power for internal board power supplies via cable DCPL to the PSCD board. The control power supply is designed to operate over a range of 60 to 600 V dc on the dc link.
Auxiliary diodes DM5 allow stored energy in the exciter to be returned to the dc link when the output contactor MDA opens. Excessive voltage buildup in the dc link during regeneration is controlled through the dynamic discharge circuit. This circuit monitors the level of the dc link and will dissipate energy through the dynamic discharge resistor (RDD) mounted at the top of the panel to prevent overvoltage of the power circuit and board rack supply. The C leg of the 3-phase IGBT pack is controlled by the dynamic discharge circuitry on the GDDD board. An alternate source of power for the discharge circuit is provided through the RDS resistor, also to the GDDD board, in the event that control power is lost. Jumper settings on the GDDD board set the control level of th e dc link by the dynamic discharge circuit.
IGBT And IAXS Devices
The dc link also provides th e unregulated power source for the Insulated Gate Bi- polar Transistor (IGBT) bridge used to provide the exciter field current. The bridge
consists of legs A and B of the 3-phase, 50 A, 1200 V IGBT pack. Only leg A upper and leg B lower IGBT’s are active. Leg A lower and leg B upper are permanently inactive. Controlled by the microprocessor-based digital regulator, the leg A and B are modulated to pulse the dc link supply and feed the resulting output to the field of the rotating brushless exciter. The output voltage is determined by th e following formula:
Voutput = Vinput * (time on/(time on + time off))
where Vinput is the dc link voltage, time on is the conduction time of the IGBT devices and time off is the non-conduction time of the IGBTs. The chopping frequency of the IGBTs is approximately 1000 Hz.
GEH-6375A User's Guide Chapter 2 Hardware System Description • •• • 2-7
The IAXS board provides the connection of the dc link capacitors to the IGBT bridge, dynamic discharge control and gate control from the GDDD board. The
IAXS board is also the connection point for the dc output voltage and sensing feedbacks to the control circuitry.
Output Contactor MDA
The output contactor MDA is described in GEK −83756. It is a double pole, single
throw, 600 V dc, 50 A contactor, isolating the positive leg of the bridge output. The second pole is used to remove the charge control resistor RCH. The power for the contactor coil is provided from the PSCD board. This voltage is only present when the control has been commanded to run. When the dc link voltage is not present, there is no power available to drive this contactor.
Output Shunt SHA
The output current is monitored by the control via the 100 MV feedback shunt SHA. The shunt rating is application specific. A range from 1 A to 25 A maximum is possible. The shunt rating must be less than twice the exciter amps full load.
Control Electronics Module
The control electronics module contains powerful programmable microprocessors with companion circuitry, including EEPROM, to process the application software. It is a module assembly that is located on the front door assembly of the power
conversion module. Elementary diagram sheet A04 and Figure 2-7 shows the connections of the various boards in the control module.
This control module assembly contains the main processor board (LDCC),
microprocessor application board (TCCB), power supply and contactor driver board (PSCD), and the gate driver board (GDDD). These boards are interconnected
through ribbon cables. Each board has a unique GEI, which documents the hardware layouts, test points, fuses and other information for each individual board. These are referenced in Chapter 1.
The LAN and Drive Control board (LDCC), which is the main processor board, provides the IGBT gating circuit control and regulator functions including: The LDCC board also
contains both isolated and non-isolated circuits for communication inputs to the exciter's controller. The LED display and keypad
programmer is on this board.
• automatic voltage regulator
• field current regulator • field current limit regulator • volts/hertz limit regulator • reactive current compensation • under-excitation limit regulator
Optional functions include:
• VAR/power factor regulator • power system stabilizer
2-8 •• • • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
TCCB (DS200TCCB)
The microprocessor application board (TCCB) is essentially a transducer board. The isolated and scaled generator PT and CT signals are fed from the PTCT board to the TCCB board. The TCCB uses voltage controlled oscillators (VCOs) to transform the analog voltage signals into digital signals. Software transducers process the voltage and current signals and then calculate generator data. This information is passed to the LDCC control processors for use by the regulators. The regulator simulation software also resides in the TCCB.
PSCD (IS200PSCD)
The Power Supply and Contactor Driver board (PSCD) is powered from the dc link through stabon terminals DCPL1 (+) and DCPL2 (). The control operates from 80 -400 V dc as nominal range inputs. Transient operation to 600 V dc is possible during maximum operation of the dynamic discharge. This board produces control power for distribution to the other control module boards. The main supply produces±24 V,
±15 V, and +5 V for control boards (LDCC and TCCB) A 17.7 V ac squarewave is
distributed through high frequency transformers to the gate driver and LTB inputs power supplies. Auxiliary to the main supply are supplies for generating isolated 70
V dc (sufficient to power 13 LUP inputs ) and an isolated SHVI/SHVM power for future applications.
The contactor control power supply from the PSCD board is sized to deliver up to 0.75 A dc. Power is taken directly from the dc link and converted to 105 V dc by a buck converter. The enable of the MDA contactor is through an optically coupled
signal, which is logically in parallel with the coil of K1. Relay K1 is driven from the LDCC board when the control is commanded to run.
Relay K86 is used as the controls permissive to run and emergency stop. Dropping out K86 will immediately stop the regulator. Coil voltage is from the 70 V dc power supply on the PSCD board.
GDDD (IS200GDDD)
The Gate Driver and Dynamic Discharge board (GDDD) provides the interface isolation between the IGBTs and the main processor firing circuits. Dynamic discharge circuit control is implemented on the GDDD board as well as the gating circuits for the A and B leg active IGBTs.
This board also provides the instrumentation of the r egulator. Output dc voltage, dc link voltage, shunt current mV input, and th e heat sink thermistor input are processed on the GDDD board and sent to the LDCC processors for use by the regulators.
PTCT (DS200PTCT)
The Potential Transformer Current Transformer (PTCT) board isolates and scales th e voltage and current signals from the PTs and CTs. It also provides auxiliary inputs and outputs for either low voltage (± 10 V dc) or 4-20 mA current signals.
Secondaries of the isolation transformers are passed to the TCCB board through the JKK ribbon connector.
GEH-6375A User's Guide Chapter 2 Hardware System Description • •• • 2-9
NTB/3TB (531X305NTB)
The NTB/3TB serves as a general purpose terminal connection board. Connections are made as an interface between the control core and other devices. Th e RS-232C serial port is located on this board. When supplied, the field ground detection inputs from the ground detector receiver are connected to the auxiliary VCO inputs on the NTB/3TB board.
LTB (531X307LTB)
The LAN Terminal Board (LTB) is an I/O termination board that serves as an interface between the control core and other devices. Ribbon cable RPL allows software variables pointed to the seven low voltage, low current, form C LTB output relays to control higher voltage, higher current, form C RTBA board relays. Jumper settings on the RTBA board determine if the LTB relays or external connections operate the RTBA relays. The eight LTB (or LUP) inputs are connected to the LDCC board through 8PL for use by the regulator controls.
RTBA (DS200RTBA)
The Relay Terminal Board (RTBA) board contains seven form C, DPDT relays that can be software driven via the LTB pilot relays or externally driven. The relay contact outputs are used for external customer interface. Each relay contains an LED that indicates when the relay is energized.
ACNA (DS200ACNA)
The Status_S data link connection to the turbine controller is made on the ACNA board.
The ARCNET Board (ACNA) serves as the connection for the ARCNET data link for the regulator. Termination is made using co-axial cable. Each ACNA can terminate two co-axial cables.
Inputs and Outputs
The regulator has a limited amount of hard inputs and outputs (I/O) that can be supported. For most applications, these are to be conducted over the Status_S data link. The following sections define the minimum I/O that must be supported.
Generator Inputs
Potential Transformer Inputs
Up to three sets of 3-phase PT inputs are supported. These inputs are a nominal 120 V secondary with software adjustments available for other nominal secondary voltages. The inputs are less than a 10 VA burden on the PT inputs.
The first two PT sets are used to supply generator line voltage feedback information to the automatic (ac) regulator for control of the generator output voltage. The first PT set is used for generator control. The second set is used for PT failure detection and can be configured for control should the first set fail.
These inputs also supply speed/frequency feedback information for the regulators, limiters, and protection functions, including the optional Power System Stabilizer (PSS).
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2-10 • • ••• • • • CChhaapptteer r 2 H2 Haarrddwwaarre e SSyysstteem m DDeessccrriippttiioonn EEXX22000000, , PPWWM M DDiiggiittaal l RReegguullaattoor Gr GEEHH--66337755AA
Optional PT isolation Optional PT isolation switches for all t
switches for all three sets of hree sets of inputs may be
inputs may be supplied.supplied.
The third set of 3-phase PT inputs provides line side voltage and is used by the The third set of 3-phase PT inputs provides line side voltage and is used by the control for an optional voltage
control for an optional voltage matching feature. These connections are madematching feature. These connections are made directly to the PTCT board.
directly to the PTCT board.
Current Transformer Inputs
Current Transformer Inputs
Optional CT isolation Optional CT isolation shorting sw
shorting switches for eachitches for each phase input may be s
phase input may be supplied.upplied.
One set of 2-phase CT inputs is supported. Phase A and phase C currents are One set of 2-phase CT inputs is supported. Phase A and phase C currents are required by the r
required by the r egulator. These CTs supply generator line current feedback egulator. These CTs supply generator line current feedback information for use by regulator, limiters, and metering functions in the
information for use by regulator, limiters, and metering functions in the brushlessbrushless regulator control, including the
regulator control, including the optional Poweoptional Power r System Stabilizer (PSS). The inputsSystem Stabilizer (PSS). The inputs require a nominal 5
require a nominal 5 A secondary CT input. Software adjustments are available downA secondary CT input. Software adjustments are available down to a nominal 3 A secondary input. The CT burden is less than 1
to a nominal 3 A secondary input. The CT burden is less than 1 VA per phase. TheseVA per phase. These connections are made directly to the
connections are made directly to the PTCT board.PTCT board.
4-20 mA Inputs
4-20 mA Inputs
Optionally
Optionally, the r, the regulator can support two 4 to egulator can support two 4 to 20 mA inputs for 20 mA inputs for signals used tosignals used to modify the overexcitation limiter/prote
modify the overexcitation limiter/protection based on ction based on the cooling of the generator.the cooling of the generator. On air cooled generators this input is
On air cooled generators this input is proportional to the cooling air temperature for proportional to the cooling air temperature for the generator. On hydrogen cooled generators this input is
the generator. On hydrogen cooled generators this input is based on hydrogenbased on hydrogen pressure of the
pressure of the generator.generator.
Generator Line Breaker Status
Generator Line Breaker Status
One form A contact input from the generator output circuit breaker is used by One form A contact input from the generator output circuit breaker is used by control, limiter, and protection functions. This contact is connected to an
control, limiter, and protection functions. This contact is connected to an LTB input.LTB input. The contact may be powered using the 70 V dc supply from the PSCD board.
The contact may be powered using the 70 V dc supply from the PSCD board.
Generator Lock-Out Trip
Generator Lock-Out Trip
One form A (closed when r
One form A (closed when r eset) contact input from a customer trip relay (86Geset) contact input from a customer trip relay (86G typically) is supported for an
typically) is supported for an external trip of the excitation control system. Thisexternal trip of the excitation control system. This contact must be powered from the 70 V dc power supply on the PSCD board. contact must be powered from the 70 V dc power supply on the PSCD board.
G
GEEHH--66337755A A UUsseerr''s s GGuuiiddee CChhaapptteer r 2 2 HHaarrddwwaarre e SSyysstteem m DDeessccrriippttiioonn ••• • • • • • 2-11 2-11
Additional I/O
Additional I/O
In addition to the
In addition to the I/O listed above, Table 2-1 lists minimum inputs and outputs thatI/O listed above, Table 2-1 lists minimum inputs and outputs that are supported.
are supported.
Note
Note Not all applications will require each Not all applications will require each of the contact I/O or 4-20 mof the contact I/O or 4-20 m A inputs or A inputs or outputs listed. Refer to the job specific elementary for those supplied.
outputs listed. Refer to the job specific elementary for those supplied.
Table 2-1 Minimum Inputs and Outputs supported Table 2-1 Minimum Inputs and Outputs supported IInnppuutt//OOuuttppuut t DDeessccrriippttiioonn Input Regulator On / Off
Input Regulator On / Off (Closed = Regulator On) (Closed = Regulator On)
Used to start and stop the brushless regulator. Used to start and stop the brushless regulator. Input Regulator Selector AC/DC
Input Regulator Selector AC/DC (Closed = AC )
(Closed = AC )
Used to select the controlling regulator, auto (ac) Used to select the controlling regulator, auto (ac) or manual (dc).
or manual (dc). Input Regulator Raise (Close =
Input Regulator Raise (Close = Raise)
Raise)
Interfaces to the active regulator’s reference Interfaces to the active regulator’s reference adjuster, ac or dc, and raises the setpoint. adjuster, ac or dc, and raises the setpoint. Input Regulator Lower (Close =
Input Regulator Lower (Close = Lower)
Lower)
Interfaces to the active regulator’s reference Interfaces to the active regulator’s reference adjuster, ac or dc, and lowers the setpoint. adjuster, ac or dc, and lowers the setpoint. Input PSS Enable/Off (Closed =
Input PSS Enable/Off (Closed = Enable)
Enable)
Allows the
Allows the PSS conPSS control to trol to operate operate if minimuif minimumm load permissives are reached.
load permissives are reached. Input Status of Control Output
Input Status of Control Output Contactor
Contactor
Used to monitor the status of the MDA contactor. Used to monitor the status of the MDA contactor. Output Exciter Alarm (30EX)
Output Exciter Alarm (30EX) Provides a global exciter trouble alarm for Provides a global exciter trouble alarm for customer annunciation.
customer annunciation. Output Protective Transfer to dc
Output Protective Transfer to dc Regulator / Transfer Regulator Regulator / Transfer Regulator alarm (60EX)
alarm (60EX)
Provides an indication of an automatic transfer to Provides an indication of an automatic transfer to manual regulator.
manual regulator. O
Ouuttppuut Rt Reegguullaattoor r OOnn PPrroovviiddees as an n iinnddiiccaattiioon n tthhaat t tthhe e rreegguullaattoor r iiss operating
operating Output Exciter Trip Request
Output Exciter Trip Request (94EX)
(94EX)
Request from the regulator to immediately trip Request from the regulator to immediately trip the generator. Usually directed to the 86G the generator. Usually directed to the 86G device.
device. Output Exciter Field Ground
Output Exciter Field Ground Alarm/Tr
Alarm/Trip (64Fip (64FA or 64A or 64FT)FT)
Can be either an alarm or trip contact depending Can be either an alarm or trip contact depending on customer preference.
on customer preference.
The voltage inputs supported are: The voltage inputs supported are:
•
• Input from Exciter Field Ground Detector Alarm (+ 24 Input from Exciter Field Ground Detector Alarm (+ 24 V)V) •
• Input from Exciter FieInput from Exciter Field Ground Detectold Ground Detector Malfunction r Malfunction (+24 V)(+24 V) •
• Input from Exciter Field GInput from Exciter Field Grounround Detector Diode d Detector Diode Fault Fault (+24 V)(+24 V)
Up to four 4 to 20 mA outputs are also supported. These outputs are provided Up to four 4 to 20 mA outputs are also supported. These outputs are provided through the digital to analog converters on
through the digital to analog converters on the NTB/3TB board. They are softwarethe NTB/3TB board. They are software configurable. Typical uses are regulator output voltage, regulator output current, and configurable. Typical uses are regulator output voltage, regulator output current, and regulator balance.
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2-12 • • ••• • • • CChhaapptteer r 2 H2 Haarrddwwaarre e SSyysstteem m DDeessccrriippttiioonn EEXX22000000, , PPWWM M DDiiggiittaal l RReegguullaattoor Gr GEEHH--66337755AA
Figure 2-2
Figure 2-2. . Mechanical Mechanical Layout Layout Note
GEH-6375A User's Guide Chapter 2 Hardware System Description •• • • 2-13
2-14 • •• • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
GEH-6375A User's Guide Chapter 2 Hardware System Description •• • • 2-15
2-16 • •• • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
GEH-6375A User's Guide Chapter 2 Hardware System Description •• • • 2-17 MAIN PROCESSOR BOARD LDCC MICROPROCESSOR APPLICATION BOARD TCCB POWER SUPPLY AND CONTACTOR DRIVER BOARD PSCD
GATE DRIVER AND DYNAMIC DISCHARGE BOARD GDDD PTCT BOARD ARCNET BOARD ACNA LTB RTBA NTB/3TB POWER CONVERTER MODULE (IGBT) WORK STATION CONTACT INPUTS CONTACT OUTPUTS CONTACT INPUTS/OUTPUTS TO TURBINE CONTROL OPERATOR INTERFACE METER DRIVER OUTPUTS QTY (4) 3 PHASE VOLTAGE SENSING INPUT 2 PHASE CURRENT SENSING INPUT RS232 PORT DC OUTPUT TO EXCITER FIELD AC INPUT DC INPUT 1PL 3PL,2PL 2PL GDPL,PPL DCPL, MDPL JKK 4 PL, 2PL GPL, 8PL IOPL, 8PL ARCPL CPL RPL
2-18 • •• • Chapter 2 Hardware System Description EX2000, PWM Digital Regulator GEH-6375A
GEH-6375A User's Guide Chapter 3 Software System Overview • •• • 3-1
Chapter 3 Software System Overview
Introduction
The regulator uses microprocessor-based software that includes adjustable parameters. These parameters perform many functions once controlled through
adjustable hardware and software combinations.
The parameters are modified to customize the regulator to the specific hardware and application. They also enable field and maintenance personnel to fine tune the regulator for optimal performance.
Use the Control System Toolbox (toolbox) and LDCC board programmer to make software adjustments. Section Page Configuration Tools ... 3-2 Programmer Module ... 3-2 Software Design... 3-2 Standard Functions... ... 3-3 Automatic Voltage Regulator (AVR) Ramp... 3-3 Automatic Voltage Regulator Setpoint... 3-3 Automatic Voltage Regulator ... 3-3 Field Regulator (FVR) Ramp... 3-3 Field Regulator... ... 3-3 Under Excitation Limiter (UEL) ... 3-4 Over Excitation Limiter (OEL)... 3-4 Firing Block ... 3-4
3-2 •• • • Chapter 3 Software System Overview EX2000, PWM Digital Regulator GEH-6375A
Configuration Tools
The toolbox is used to configure, maintain, and fine tune the regulator. It in cludes an extensive database of definitions, accessed and manipulated using menu driven selections. Additionally, the toolbox can graphically display the exciter's program logic on the computer screen. By viewing the logic flow, you can better understand and manipulate the exciter's adjustable values.
The toolbox is used at the factory to initially configure and test the systems. At the customer site, it enables GE field engineers and other trained personnel to
troubleshoot, fine-tune, and maintain the in stalled regulator. Optional tool based modules provide real display of control variables and communications data. Refer to GEH
−
6404 for more information and PC requirements.Programmer Module
The regulator includes a programmer module with a 16-character digital display and an alphanumeric keypad. It functions as an operator interface for software
adjustments and diagnostic testing when the toolbox is n ot available.
Note Permanent changes made using the programmer module must also be made in the toolbox to keep them up to date with the exciter's software configuration. Get contact information from GEI
−
100242.Refer to GEI
−
100242 for more information on the programmer module.Software Design
The exciter application consists of functional software modules (blocks) combined to perform to system requirements. Block definitions and configuration parameters are
stored in read-only memory (ROM), while variables are stored in random-access memory (RAM). Microcontrollers execute the code.
The exciter application emulates traditional analog controls. The software uses an open architecture system, which uses a library of existing software blocks. The blocks individually perform specific functions, such as logical AND gates,
proportional integral (PI) regulators, function generators, and signal level detectors. These blocks are tied together in a pattern to implement complex control systems. For example, a control function such as the under-excitation limit (UEL) is included as an ac regulator input by setting software jumpers in EEPROM. The relevant
blockware is enabled by pointing the block inputs to RAM locations where the inputs reside (the UEL requires megawatts, kilovolts and megavars). The UEL output is then pointed to an input of the ac regulator summing junction.
This technique is similar to tracing an analog signal by using a voltmeter.
The software blocks are sequentially implemented by the block in terpreter in an order and execution rate d efined in the toolbox. The blockware can be interrogated while running by using the toolbox. The dynamically changing I/O of each block can be observed in operation.
GEH-6375A User's Guide Chapter 3 Software System Overview • •• • 3-3
Standard Functions
These inputs and outputs can be monitored through the toolbox.
Table 3-1 is a description of the inputs and outputs for the more significant blocks used in the exciter. Also, the significant adjustments of those functional blocks are described as adjustable constants. These constants represent limits, gains, and setpoints. They are functionally equivalent to potentiometers or other discrete adjustment devices used in previous excitation systems.
Automatic Voltage Regulator (AVR) Ramp
The AVR ramp block accepts an input from the operator through the Status-S page for auto regulator raise or lower. The reference then ramps at a predetermined rate, within an upper and lower limit (usually 0.9 to 1.1 pu terminal V). The output can be preset to a value upon startup. Automatic tracking of the AVR track value is
performed when operating in manual regulator (refer to Figure 3-2).
Automatic Voltage Regulator Setpoint
The AVR setpoint block sums the output from the reactive current compensation (RCC), AVR ramp, UEL output, and power system stabilizer (PSS) output. This sum is compared to the V/Hz reference in a minimum select block and then passed through a high limiter as the AVR output signal. By selecting a negative or positive gain, line-drop or droop compensation mode may be selected on the RCC. An auto/manual command by the operator generates auto active or manual active status indicators. A PT failure can also select manual (refer to Figure 3-3).
Automatic Voltage Regulator
The AVR block combines the AVR setpoint with the n egative generator terminal volts to provide an error signal. This is passed through to the automatic regulator proportional and integral gain sub-blocks, and then passes through the auto regulator
limits to the manual voltage regulator (refer to Figure 3-4). The auto regulator is modeled by the following transfer function:
AVR out = AVR error (Kp + KI)/S
Field Regulator (FVR) Ramp
The FVR ramp block accepts an input from the operator through the Status-S page for manual regulator raise or lower. The reference then r amps at a predetermined rate within an upper and lower limit (usually 0.7 pu VFNL to 1.2 pu VFFL). The output can be preset to a value upon startup. When in auto regulator mode, the FVR ramp tracks the value of exciter field current (IFE) (refer to Figure 3-5).
Field Regulator
The exciter field regulator is configured as a current regulator. The reference input to the FVR is from either the manual r egulator ramp block or the AVR. When fed from the AVR, the field regulator is used a s an inner loop. A bridge firing enabled signal is also provided to keep the exciter turned off until bridge firing is enabled (refer to Figure 3-6).