Post on 08-Mar-2018
Generic Models for Static VAr Systems
Pouyan Pourbeikppourbeik@epri.comEPRI HVDC & FACTS ConferenceAugust 30, 2011
2© 2011 Electric Power Research Institute, Inc. All rights reserved.
THE DEFINITION OF AN SVS
• Static Var System = any combination of power electronic controlled/switched shunt device + coordinated mechanically switched shunt elements
(reproduced from [3], © IEEE 2005)
TCR
TSC
MSC
Control Strategy
Vbus
Vref
slope
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THE TECHNOLOGIES
• Basic building blocks:
(reproduced from [3], IEEE © 2006)
SVC STATCOM
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WORK THAT WAS DONE
• EPRI Worked in collaboration with the WECC SVC TF
• WECC SVC TF Chair: Janet Kowalski, SCE
• Goal was to develop new models for SVS for– powerflow planning studies– System stability planning studies
• Share results publicly to get the models into the commercial tools (e.g. GE PSLF®, Siemens PTI PSS®E, PowerWorld, PowerTech Labs etc.)
• Participants in the group:– ABB, EPRI, GE, PG&E, Mitsubishi, NERC, SCE, Siemens, TEP,
WECC– Many others provide comments (S&C, AMSC, etc.)– See full TF report [1]
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OLD MODELS vs NEW MODELS
• Previously many models in commercial tools (such as GE PSLF® and Siemens PTI PSS®E) for modeling SVCs and STATCOMS.
• Although these models have served a great purpose, the technology has since advanced
• The old standard library models could not (typically):– Model relevant protection and short-term ratings– PI regulators– Slow-susceptance regulator– Coordinate switching of MSSs– Deadband (if implemented)– In power flow model slope, coordinate MSS switching and slow-
susceptance regulator• Not being able to model the above means not really being able to
assess the functionality of modern equipment in planning studies• The new models do capture these (and some more) functionalities
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WHAT IS MODELED IN THE NEW MODELS
– The voltage regulator– The coordinated switching logic for MSSs (B based
switching; V base is a separate complementary model)
– The slow-susceptance regulator (optional)– Deadband control (optional)– SVC slope/droop (non-linear, optional)– SVC limits, over- and under-voltage strategy and
voltage trip set points (protection)– Any short-term rating capability– Power Oscillation Damper is a separate
complimentary model
7© 2011 Electric Power Research Institute, Inc. All rights reserved.
WHAT IS NOT MODELED
– The TCR and TSC current limits – Secondary Voltage Limitation (may in some cases need to be
modeled, e.g. some STATCOM applications)
– Gain scheduler – Main other controls and details (cooling system
controls etc.) that have little to no bearing for system dynamic performance studies.
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VI CHARACTERISTIC
STATCOM SVC
(not to scale, explanation tool only)
Cap. ICap. I Ind. IInd. I
V
V
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TERMINOLOGY
• SVSMO1 – model of a TCR based SVS
• SVSMO2 – model of a TSC/TSR based SVS
• SVSMO3 – model of a VSC based SVS
DYNAMIC MODELS
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THE GENERIC SVSMO1 MODEL
Vsig
+-
S0 Vemin
BmaxVemax
Bsvc (p.u.)Vbus
Linear or Non-Linear Slope Logic
1 + sTb1
1 + sTc1
+S4
1 + sTb2
1 + sTc2
S2
1 + sT2
1
S1
s Kiv
Kpv+
Bmin
X
MSS SwitchingLogic based on
B
MSS1......
MSS8
Isvc
DeadbandControl
(Optional)
VrefmaxVrefmin
+
Vrmax
S3
s Kis
Kps+
Vrmin
+
++
Bref control logic
BSVC (MVAr)
Bref
-+
Berr Vsched
Verr
Vr
SVC over-and under-
voltage tripping function
B
VcompVr
Vref
Over Voltage Strategy,Under Voltage
Strategy& Short-Term Rating
externally controllable
externally controllable
pio2
pio1
12© 2011 Electric Power Research Institute, Inc. All rights reserved.
THE GENERIC SVSMO2 MODEL
Vsig
+-
S0Vemin
BmaxVemax Bsvc (p.u.)
Vbus
Linear or Non-Linear Slope Logic
1 + sTb1
1 + sTc1
+S4
1 + sTb2
1 + sTc2
S2
1 + sT2
1
S1
s Kiv
Kpv+
Bmin
X
MSS SwitchingLogic based on
B
MSS1......
MSS8
Isvc
VrefmaxVrefmin
+
Vrmax
S3
s Kis
Kps+
Vrmin
+
++
Bref control logic
BSVC (MVAr)
Bref
-+
Berr Vsched
Verr
Vr
SVC over-and under-
voltage tripping function
B
VcompVr
Vref
Over Voltage Strategy,Under Voltage
Strategy& Short-Term Rating
pio2
pio1Look-up
Tabledbe-dbe
dbb-dbb
Look-up tablefinds B closest to Bcommand
(Bcommand)
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THE GENERIC SVSMO3 MODEL
POWERFLOW MODELS
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TCR BASED SVS – SVSMO1
• Model slope • Allow seamless connection of shunt model to dynamics
model• Model MSS switching• Emulate slow-susceptance regulator• EMULATION – cannot exactly predict sequence
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TSC/TSR BASED SVS – SVSMO2
• Key is to be able to model combination of TSC/TSRs• Model coordinated MSS switching• Allow seamless connection of shunt model to dynamics
model
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VSC BASED SVS – SVSMO3
• Model slope • Allow seamless connection of shunt model to dynamics
model• Model MSS switching
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REVIEW OF MODELS AND TESTING
• Extensive testing done by:– EPRI (on svsmo1, svsmo2 and svsmo3)– Mitsubishi (on svsmo1)– GE (on svsmo1, svsmo3)– Siemens PTI (on svsmo1, svsmo2)
MODEL VALIDATION DONE BY EPRI
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VALIDATION USING DFR RECORDING (SVSMO1) (similar to EPRI PPPD approach [2])
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VALIDATION USING DFR RECORDING (SVSMO1)
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VALIDATION USING DFR RECORDING (SVSMO1)
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VALIDATION USING DFR RECORDING (SVSMO1)
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VALIDATION USING DFR RECORDING (SVSMO3)
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CONCLUSIONS
• Three new SVS models developed
• Approved within WECC
• Are now implemented and available in the latest versions of GE PSLF® and Siemens PTI PSS®E; also have sent code to PowerWorld and PowerTech Labs
• Tested and validated against measured disturbance data
• Vendors were major participants in the effort
• EPRI held a successful workshop on these models in Charlotte, NC in September 2010
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REFERENCES
[1] Generic Static Var System Models for the Western Electricity Coordinating Council, WECC SVC TF, April, 2011 (www.wecc.biz)
[2] P. Pourbeik, “Automated Parameter Derivation for Power Plant Models From System Disturbance Data”, Proceedings of the IEEE PES General Meeting, Calgary, Canada, July 2009.
[3] P. Pourbeik, M. P. Bahrman, E. John and W. Wong, “Modern Countermeasures to Blackouts”, IEEE Power and Energy Magazine, Vol. 4, No. 5, September/October 2006,pp. 36-45.
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