2014 PV Distribution System Modeling Workshop: Data and Models for High Penetration Using Advanced Inverters: Roger Dugan, EPRI

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2014 PV Distribution System Modeling Workshop: Data and Models for High Penetration Using Advanced Inverters: Roger Dugan, EPRI

2014 PV Distribution System Modeling Workshop: Data and Models for High Penetration Using Advanced Inverters: Roger Dugan, EPRI

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  • 1. Roger C. Dugan Sr. Technical Executive Sandia-NREL-EPRI PV Distribution System Modeling Workshop May 6, 2014 Santa Clara, CA Data and Models for High-Penetration PV Using Advanced Inverters
  • 2. 2© 2014 Electric Power Research Institute, Inc. All rights reserved. Objective • Data and modeling requirements for advanced, or smart, inverter functions will be illustrated using the modeling requirements for the EPRI OpenDSS program
  • 3. 3© 2014 Electric Power Research Institute, Inc. All rights reserved. The OpenDSS PVSystem Model With Smart Inverter Control Can Demonstrate Benefits
  • 4. 4© 2014 Electric Power Research Institute, Inc. All rights reserved. The basic volt-var control function can be described by four P, Q points This control is effective where the voltage level will respond to vars – where the system impedance is Inductive
  • 5. 5© 2014 Electric Power Research Institute, Inc. All rights reserved. Adding hysteresis to the volt-var curve is sometimes beneficial in controlling voltage Implementations of this model may require more points simply implement shifting logic to a base curve
  • 6. 6© 2014 Electric Power Research Institute, Inc. All rights reserved. Modeling the advanced inverter is demonstrated with an OpenDSS example based on this circuit
  • 7. 7© 2014 Electric Power Research Institute, Inc. All rights reserved. An actual 10-min PV system Active Power measurement will be used for the example New "LoadShape. PV_ls" npts=600 sinterval=1.0 mult=(File=“Solar-600s.csv") OpenDSS Script for Defining This as a “Loadshape”: File containing 600 pts
  • 8. 8© 2014 Electric Power Research Institute, Inc. All rights reserved. This OpenDSS script snippet defines the four PV systems New PVSystem.3P_ExistingSite4 phases=3 bus1=B51854_sec kV=0.4157 kVA=523 ~ irradiance=1 Pmpp=475 pf=1 %cutin=0.1 %cutout=0.1 yearly=PV_ls New PVSystem.3P_ExistingSite1 phases=3 bus1=X_5865228330A kV=0.4157 kVA=314 ~ irradiance=1 Pmpp=285 pf=1 %cutin=0.1 %cutout=0.1 yearly=PV_ls New PVSystem.3P_ExistingSite3 phases=3 bus1=X_5891328219_Cust1 kV=0.4157 ~ kVA=836 irradiance=1 Pmpp=760 pf=1 %cutin=0.1 %cutout=0.1 yearly=PV_ls New PVSystem.3P_ExistingSite2 phases=3 bus1=B4832_sec kV=0.4157 kVA=209 ~ irradiance=1 Pmpp=190 pf=1 %cutin=0.1 %cutout=0.1 yearly=PV_ls •Bus Name (Bus1) •Voltage rating (kV) •kVA rating (kVA) •Base irradiance (kW/m2) •Power at MPP (Pmpp) •Base power factor (pf) •Cut in/cut out percentage values •Irradiance Loadshape for OpenDSS solution mode (yearly in this case to get desired monitoring) •Inverter Efficiency curve (optional) •Pmpp vs Temperature curve (optional) Data for PVSystem Model
  • 9. 9© 2014 Electric Power Research Institute, Inc. All rights reserved. The base-line simulation reveals voltage and power excursions Note: Unity PF assumed for base-line
  • 10. 10© 2014 Electric Power Research Institute, Inc. All rights reserved. Implementation of a simple volt-var control requires definition of a curve and an InvControl New XYCurve.vv_curve npts=4 Yarray=(1.0,1.0,-1.0,-1.0) XArray=(0.5,0.95,1.05,1.5) New InvControl.InvPVCtrl mode=VOLTVAR voltage_curvex_ref=rated ~ vvc_curve1=vv_curve EventLog=yes Volt-Var Control Curve Definition Inverter Control Definition pu Voltagepu Rated Vars
  • 11. 11© 2014 Electric Power Research Institute, Inc. All rights reserved. Results with simple volt-var control show the voltage is reduced about 2% to less than 105%
  • 12. 12© 2014 Electric Power Research Institute, Inc. All rights reserved. Modeling hysteresis is accomplished by adding an offset to the voltage (x axis) New XYCurve.vv_curve npts=4 Yarray=(1.0,1.0,-1.0,-1.0) XArray=(0.5125,0.9625,1.0625,1.5125) New InvControl.InvPVCtrl mode=VOLTVAR voltage_curvex_ref=rated ~ vvc_curve1=vv_curve hysteresis_offset=-0.025 EventLog=yes
  • 13. 13© 2014 Electric Power Research Institute, Inc. All rights reserved. The reactive power output level is constant when power flow between curves
  • 14. 14© 2014 Electric Power Research Institute, Inc. All rights reserved. The solutions on the VV curves with hysteresis indicate the inverter drawing vars to reduce V
  • 15. 15© 2014 Electric Power Research Institute, Inc. All rights reserved. Volt-Var control with adaptive set point attempts to follow the voltage more closely over time New InvControl.InvPVCtrl mode=VOLTVAR voltage_curvex_ref=avg avgwindowlen=2m ~ vvc_curve1=vv_curve EventLog=yes
  • 16. 16© 2014 Electric Power Research Institute, Inc. All rights reserved. Adding a 5-s time constant on the rate of change significantly smooths the var response New InvControl.InvPVCtrl mode=VOLTVAR voltage_curvex_ref=rated ~ vvc_curve1=vv_curve RateofChangeMode=LPF LPFTau=5 EventLog=yes
  • 17. Data Requirements for Other Control Functions
  • 18. 18© 2014 Electric Power Research Institute, Inc. All rights reserved. The Volt-Watt Function suppresses active power output for high voltages New XYCurve.examplevoltwattcurve npts=4 Yarray=(1.0,1.0,0.0,0.0) XArray=(0.0,1.0,1.1,2.0) New InvControl.InvPVCtrl mode=VOLTWATT voltage_curvex_ref=rated ~ voltwatt_curve=examplevoltwattcurve EventLog=yes Optional DATA: Rolling average window length Units for Y axis Rate-of-change mode: INACTIVE | LPF | RISEFALL Low-Pass Filter time constant for rate of change of output power RiseFall Limit (pu/s or kW/s)
  • 19. 19© 2014 Electric Power Research Institute, Inc. All rights reserved. The Dynamic Reactive Current function provides reactive current in response to dynamic variations in voltage New InvControl.InvTestPVCtrl mode=DYNAMICREACCURR DbVMin=0.975 DbVMax=1.025 ~ ArGraLowV=10.0 ArGraHiV=10.0 DynReacavgwindowlen=120s EventLog=yes Optional DATA: Var change tolerance; default is 0.025 pu of available vars
  • 20. 20© 2014 Electric Power Research Institute, Inc. All rights reserved. The Dynamic Reactive Current control can help reduce voltage sags and swells during transient events
  • 21. 21© 2014 Electric Power Research Institute, Inc. All rights reserved. Fixed Power Factor control is a simple function that reduces voltage swings and high voltages New PVSystem.3P_ExistingSite4 phases=3 bus1=B51854_sec kV=0.4157 kVA=523 ~ irradiance=1 Pmpp=475 pf=-0.98 %cutin=0.1 %cutout=0.1 yearly=PV_ls
  • 22. 22© 2014 Electric Power Research Institute, Inc. All rights reserved. This example of the Max Generation Limit function limits PV system output to 70% or Pmpp New PVSystem.3P_ExistingSite4 phases=3 bus1=B51854_sec kV=0.415692194 kVA=523 ~ irradiance=1 Pmpp=475 kvar=0.00 pctPmpp=70.0 %cutin=0.1 %cutout=0.1 ~ yearly=PV_ls
  • 23. 23© 2014 Electric Power Research Institute, Inc. All rights reserved. This example demonstrating OpenDSS scripting for switching from V-W control to V-V control New XYCurve.myvw_curve npts=4 ~ Yarray=(1.0,1.0,0.0,0.0) ~ XArray=(0.5,1.0,1.05,1.5) New InvControl.InvTestPVCtrl mode=VOLTWATT ~ voltage_curvex_ref=rated ~ voltwatt_curve=myvw_curve EventLog=yes set casename= voltwatt300_voltvar300 solve mode=yearly number=300 stepsize=1s New XYCurve.myvv_curve npts=4 ~ Yarray=(1.0,1.0,-1.0,-1.0) ~ XArray=(0.5,0.95,1.05,1.5) InvControl.INVPVCTRL.mode=VOLTVAR InvControl.INVPVCTRL.voltage_curvex_ref=rated InvControl.INVPVCTRL.vvc_curve1=myvv_curve Solve number=300
  • 24. 24© 2014 Electric Power Research Institute, Inc. All rights reserved. “Loadshape” data, typically in 1-s intervals, is key to many advanced inverter simulations
  • 25. 25© 2014 Electric Power Research Institute, Inc. All rights reserved. Questions?