Presentation on theme: "User Experience with New Solar PV Models California ISO"— Presentation transcript:
1 User Experience with New Solar PV Models California ISO Irina GreenRegional Transmission Engineering LeadCalifornia ISOWECC Renewable Energy Modeling WorkshopJune 17, 2014
2 Solar PV Plant Representation Power FlowTransient Stability
3 Transient Stability Models. Large Solar PV Plant REGC_A module - Generator/Converter interface with the grid. Typical parameters from the WECC GuidelinesREEC_B module - Electrical Controls of the inverters. Typical parameters from the WECC Guidelines except for Integral Gain (Kvi) and Transducer Time Constant (Trv). Reduced Kvi from 100 to 40 to avoid oscillations. Kvi=40 typical for the PV1E model. Was a typo in the Trv, changed from 0.2 to 0.02REPC_A module - Plant Controller. It processes voltage and reactive power output to emulate Volt/Var control at the plant level. Typical parameters from the WECC Guidelines
4 3-Phase Fault on the Solar Switching Station 3-Phase Fault on the Solar Switching Station. Voltage on the equivalent PV generator terminalsTrv = 0.2, Kvi = BLUETrv = 0.02, Kvi = REDTrv = 0.02, Kvi = 40 - GREEN
5 Study Example 2023 Heavy Summer Case. 800 MW Solar PV Plant Study Example Heavy Summer Case. 800 MW Solar PV Plant. Composite Load Model for all WECCThree-phase 6 cycles fault at the Switching Station 230 kV, double-line outage Switching Station – Morro Bay
7 Study Scenarios Same as 5), but A/C stalling enabled. Solar PV with 0.95 lead/lag power factor. Reactive power and voltage control; priority is reactive power. Plant controller controls voltage. Stalling of the single-phase air conditioners disabled. Same as 1), but A/C stalling enabled.Solar PV with unity power factor. No reactive support or voltage regulation. Priority is real power. Stalling of the single-phase air conditioner motor load disabled. Same as 3), but A/C stalling enabled.The Solar PV plant is replaced by a fictitious combined-cycle plant. Stalling of the single-phase air conditioner motor load components is disabled. Same as 5), but A/C stalling enabled.
8 Study Results. Switching Station Voltage Voltage recovered to the pre-fault values. Solar PV with unity power factor voltage recovered to a slightly lower value.Solar PV showed faster recovery than the combined-cycle plant.Single-phase air conditioners stalling did not have almost any impact on the voltage on this bus.
9 Study Results. Switching Station Frequency Inverter-based generators had better damping than conventional generatorsNo impact from the air-conditioner stallingHigher frequency in the first 0.5 second after the fault with solar PV
10 Study Results. Voltage on Equivalent Generator Terminals Voltage recovered to the pre-fault values, except for solar PV with unity power factor, especially with A/C stallingFaster voltage recovery and better damping with solar PVVoltage spike in the first 0.5 sec after the fault with solar PV with voltage regulationOnly slight impact of A/C stalling in PV scenario with unity power factor
11 Study Results. Frequency on Equivalent Generator Terminals Inverter-based generation has better damping than conventional generationSlow frequency recovery with solar PV that has voltage regulationMay appear as a criteria violation in transient stability studies, but this may be a numerical issueNo impact of A/C stalling
12 Study Results. Real Power Output from Equivalent Generator Solar PV generators have better damping than the thermal unitSolar PV units have slower recoveryA/C stalling doesn’t have any impact
13 Study Results. Reactive Power Output from Equivalent Generator Solar PV generators have better damping than the thermal unitAs expected, solar PV with unity power factor did not respondA/C stalling has very slight impact by increased reactive output, except for the unit with unity power factor
14 Study Results. Adjacent Load Bus Generator type doesn’t have any impact on voltage, very slight impact on frequencyDelayed voltage recovery due to stalled air-conditioners
15 Loss of LoadScenario 1: PV with voltage regulation, A/C stalling disabled – 66 MWScenario 2: PV with voltage regulation, A/C stalling enabled – 91MWScenario 3: PV with unity power factor, A/C stalling disabled – 67 MWScenario 4: PV with unity power factor, A/C stalling enabled – 96 MWScenario 5: Combined cycle plant, A/C stalling disabled – 69 MWScenario 6: Combined cycle plant, A/C stalling enabled – 97MW
16 Conclusions Scenario Transient voltage on generator terminals Post-fault steady state voltageSlow voltage recovery on adjacent load buses1 Solar PV, voltage control, induction motors don’t stallHighNormalNo2 Solar PV, voltage control, induction motors stallYes3 Solar PV, no vlt and Q control, induction motors don’t stallLow4 Solar PV, no vlt and Q control, induction motors stall5 Thermal, induction motors don’t stall6 Thermal, induction motors stall