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MISO Nihal Mohan Governor Modeling Improvement
MISONihal Mohan
Governor Modeling Improvement
Outline
• Issue found in frequency response of the models during MOD-033 model validation
• MISO Proposal for MTEP 18 Dynamic model building for governor response.
59.8600
59.8800
59.9000
59.9200
59.9400
59.9600
59.9800
60.0000
60.0200
0.00
0.28
0.55
0.83
1.09
1.37
1.64
1.92
2.19
2.47
2.74
3.02
3.29
3.57
3.84
4.12
4.39
4.67
4.94
5.22
5.49
5.77
6.04
6.32
6.59
6.87
7.14
7.42
7.69
7.97
8.24
8.52
8.79
9.07
9.34
9.62
9.89
10.17
10.44
10.72
10.99
11.27
11.54
11.82
12.09
12.37
12.65
12.92
13.20
13.47
13.75
14.02
14.30
14.57
14.85
15.12
1540
Frequ
ency
in H
z
TIme in sec
Frequency with Current Models
PMU
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MISO MOD-033 System Frequency comparison on 345 kV Bus
Frequency nadir differs
Settling frequency is optimistic.
Gen trip simulated at 0.5 sec
Conclusions: • Models are predicting system frequency settling at a higher value.• This difference is due to governor modeling (dead band, non-responsive governor). Known Issue.
Synchrophasor data
New governor models with deadband are available and have been tested
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• PTI released 14 new governor models with deadband blocks in version 33.10
• MISO comprehensively tested new models• MTEP planning models used• 4 scenarios: Summer, Shoulder with 2
wind sensitivities and Light Load model
• Converted 14 governor model type to new governor models with generic deadband settings
• 2 event validated• Results more closely match observed
performance• Frequency settles at lower value• Lazy L shape obtained IEEEG1SDU*
asymmetrical deadband
Current model without deadband
New model with deadband
Newer governor models with asymmetrical deadband modeling recommended to be used
Results from newer governor models match closely with observed real time data
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Comparison of old and new governor model performance with measured response for generator trip ~1100 MW loss, Sep 2015
Results are from 2020 Summer Dynamics case
Another Simulation Example – Generator trip
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Results of 2020 Summer Dynamics case with new governor models compared to real-time dataGenerator trip, ~1300 MW loss, July 2016
List of New Models1. IEEEG1 : IEEEG1SDU OR IEEEG1CDU ( if machine is cross –compounded) # ADDED ASYMMETRICAL DEAD-BAND, Trate2. IEESGO : IEESGODU # ADDED ASYMMETRICAL DEAD-BAND, Trate3. WESGOV : WESGOVDU # ADDED ASYMMETRICAL DEAD-BAND, Trate4. WPIDHY : WPIDHYDU # ADDED ASYMMETRICAL DEAD-BAND, Trate5. GASTWD : GASTWDDU # ONLY ASYMMETRICAL DEAD BAND6. GAST2A : GAST2ADU # ADDED ASYMMETRICAL DEAD-BAND7. GAST : GASTDU # ADDED ASYMMETRICAL DEAD-BAND, Trate8. HYGOV : HYGOVDU # ADDED ASYMMETRICAL DEAD-BAND, Trate9. TGOV1 : TGOV1DU # ADDED ASYMMETRICAL DEAD-BAND, Trate10. IEEEG3 : IEEEG3DU # ADDED ASYMMETRICAL DEAD-BAND, Trate11. DEGOV1 : DEGOV1DU # ADDED ASYMMETRICAL DEAD-BAND, Trate12. PIDGOV : PIDGOVDU # ADDED ASYMMETRICAL DEAD-BAND, Trate13. TGOV3 : TGOV3DU # ADDED ASYMMETRICAL DEAD-BAND, Trate14. HYGOV2 : HYGOV2DU # ADDED ASYMMETRICAL DEAD-BAND, Trate
BenefitsNew models enables accurate studies for :• All transient stability studies• Frequency Response (FR) Measurement per BAL-003 can
be estimated• Frequency response in 20-52 sec time frame, post a generator
trip is critical for accurate calculations. • New models show expected frequency response for 20-52
seconds• UFLS studies per PRC-006-2
• Requirement 3.3 requires 45 seconds long dynamic simulation• Helps PCs meet requirement R1.3 and 1.4 for MOD-033
(resolution for discrepancies in model behavior)Improved Dynamic Models
MISO Proposal for MTEP 2018 Dynamic Model : Dead Band Modeling• Data submitters should convert the legacy models to new model
with dead-band:• Dead-band can be intentional (implemented in plant control logic) or un-
intentional (physical dead-band)• Member should be populating intentional dead-band incorporated in the control
logic of the plant.• Engineering judgment can be used to estimate physical dead band values.
• Current models with dead-band controls should be reviewed • Majority of the data–submitters who utilize GE General Governor/Turbine
Model (GGOV1) do not populate dead-band parameter (CON J+28). This is highly unlikely.
• NOTE : MISO is NOT suggesting to utilize ±36mHz db values in models, but utilizing governor models with implemented dead-bands
MISO Proposal for MTEP 2018 Dynamic Model: Responsive Units
• Submit generator dynamic data to exhibit realistic frequency response• Data submitters provide information to disable non-
responsive governors in MTEP 18 dynamic data submission
• Data submitters add outer-loop mw controller model (LCFB1) to squelched units
How to identify Governor Responsiveness?
• Coordination with plant operators, manufacturers• Real-time data may be used to identify responsiveness of units. • Warning:
• Units may appear non-responsive, when they in fact are responsive; due to being at or near max output
• Multiple events should be utilized to determine responsiveness• Following slides contain examples from Pi Historian data utilizing
ERCOT plotting tool• BAL-001-TRE-1 PFR Evaluation - Intermittent Renewable Resource • BAL-001-TRE-1 PFR Evaluation - Single Generator Combustion
Turbine BAL-001-TRE-1 PFR Evaluation - Single Generator Steam Turbine
Pi Historian – Responsive unit
Pi Historian – Non-responsive unit
Pi Historian – Squelched unit
