Angeles Forest and Palmdale Roost 2018 Solar PV DisturbancesApril 20, 2018 and May 11, 2018 Disturbances

Ryan D. Quint, PhD, PESenior Manager, Advanced System Analytics and Modeling, NERC

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Published Disturbance Report

https://www.nerc.com/pa/rrm/ea/Pages/April-May-2018-Fault-Induced-Solar-PV-Resource-Interruption-Disturbances-Report.aspx

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Angeles Forest DisturbanceApril 20, 2018, 17:11:06 PDT

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• 17:11:06 PDT• 500 kV “bolted” line-line fault, normally cleared in 2.6 cycles• Faulted line is mixed 500 kV underground/overhead

configuration Relatively lopsided RLC line parameters, unbalanced line shunt reactors

to compensate for high capacitive charging from the underground portion of the line.

Angeles Forest Disturbance

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Angeles Forest DFR Records at Fault Location

DFR at Remote End

DFR at Local End

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CAISO BPS-Connected Solar and Net Load

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SCE BPS-Connected Solar

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PG&E BPS-Connected Solar

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LADWP BPS-Connected Solar

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Combined Cycle Unit Trip

• One natural gas turbine at a 2-on-1 combined-cycle power plant in PG&E footprint tripped off-line due to the fault event.

• Plant tripped on low fuel gas pressure, causing one natural gas turbine loaded at 125 MW to trip.

• Subsequently reduced steam turbine output from 150 MW to 75 MW over the course of 19 minutes.

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Affected Solar PV in SCE

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Palmdale Roost DisturbanceMay 11, 2018, 15:20:14 PDT

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• Fault on short 500 kV line, B-N, normally cleared in 3 cycles.

Palmdale Roost Disturbance

DFR at One End of Faulted Circuit

DFR at Other End of Faulted Circuit

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CAISO BPS-Connected Solar and Net Load

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SCE BPS-Connected Solar

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PG&E BPS-Connected Solar

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LADWP BPS-Connected Solar

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IID BPS-Connected Solar

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Affected Solar PV in SCE

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Additional Information Related to Disturbances

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Map of Fault Locations

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CAISO Solar Profiles on Days of Disturbances

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System Frequency during Disturbances

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CAISO ACE

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Findings from Disturbance Analyses

(Refer to the Disturbance Report for Associated Recommendation for Each Finding)

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• Many plants exhibited momentary cessation

• Issuance of NERC Alert for Canyon 2 Fire disturbance was around time of both disturbances Not likely any major updates

implemented by then

• Data gathered from NERC Alert shown in figure

• ERO expecting applicable GOs to implement recommendations to improve performance.

Finding 1: Continued Use of Momentary Cessation

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Finding 1a: Improved Recovery from Momentary Cessation

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Finding 2: Fault Ride-Through Performance

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Finding 3: Transient AC Overvoltage and DC Reverse Current Tripping

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Finding 4: Partial Tripping and Partial Momentary Cessation

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Finding 5: Difference between Inverter Terminal and POI Voltage

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Finding 6: Lack of High Resolution Data and Time Stamping

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Finding 7: Response of DER

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Finding 7: Response of DER

CAISO Net Load

SCE “Net Load”

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Finding 7: Response of DER

PG&E Load Buses

SCE Load Buses

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Finding 8: PDCI Performance and RAS Actions

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Finding 8: PDCI Performance and RAS Actions

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• Unit tripped due to low fuel gas pressure as the turbine control system attempted to readjust the number of burners used as the plant initiated a runback of active power output.

• One CT tripped, causing the steam turbine to also reduce output over many minutes.

Finding 9: Combustion Turbine Trip

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Disturbance Analysis Team

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Ryan Quint, PhD, PESenior ManagerAdvanced System Analytics and ModelingNorth American Electric Reliability CorporationOffice (202) 400-3015Cell (202) 809-3079ryan.quint@nerc.net