Power Systems & Energy Course: Wind and Solar Plant Modeling Jason MacDowell Alphabet Soup: Software There are several software programs used by the electric power industry for planning studies: • “PSLF” by GE EA&SE (us: Energy Consulting, EC, PSEC, PSED, EUSED, etc…) • • • “PSS/e” by PTI-Siemens (here in Schenectady) “PowerFactory” –- by DigSilent (in Germany) Other regional, specialty s/w: France: “Eurostag” Brazil: “ANDESA“ Think EXCEL vs LOTUS… China: “BPSP” Etc… © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 2/ What is a ‘model’? Utilities represent their entire system in a simulation model (using software such as GE PSLF or Siemens PSS/E ®) This model is a mathematical representation of all components in the network, such as: • Generation (Thermal, Renewables, etc…) • Transmission (Lines, Transformers, FACTS, etc…) • Loads For illustration, we’ll compare a PSLF or PSS/E ® ‘model’ to an EXCEL spreadsheet ‘model’ © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 3/ EXCEL To solve problems in EXCEL (or Lotus 123) , one needs: 1) A license to the software, sold by Microsoft (or ?) 2) A workbook file for the problem at hand 3) A library of built-in functions (e.g SQRT, NPV, etc ) Users can’t change the function, but must give it input data to produce output 4) Possibly some special MACROs, written to provide non-standard functions (e.g tax depreciation on capital equipment in Elbonia) User’s need the structure (code) of the macro AND input data 5) Data to drive calculations, functions and MACROs PSLF and PSS/E ® To solve problems in PSLF and PSS/E ®, one needs: 1) A license to the software, sold by GE or PTI-Siemens 2) A data set for the problem at hand (this is the grid “model” ) 3) A library of built-in functions (called “standard library models”), e.g GENROU (for synchronous generators), IEEEST1 (for one standard type of excitation system), GGOV1 (simple governor for gas turbines)… There may be thousands of these models in the grid model 4) Possibly some special MACROs, written to provide non-standard functions (called “user-written models”), e.g HVDC, special relays, and some wind turbine generators…) 5) Data to drive calculations, standard models, user-written models and ‘events’ Without data, the functions and MACROs don’t work Thus, the data is part of the ‘model’ © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 4/ WTG Model Development Considerations > Time-frame of Interest > Adequate Detail > Consistency with Similar Models GE WTG Models > Steady-state > Dynamic © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 5/ Time-Scale of Dynamic Performance EMTP Analysis Small Signal Analysis Fundamental Frequency Analysis High Bandwidth, Non-Linear Systems Control Design Switching Transients Harmonics & Filter Design Electro-Mechanical Interactions Transient Stability Oscillatory Stability Long-term Dynamic Stability 10 -6 10 -5 10 -4 001 01 1 cycle 10 100 1000 minute 10 hour TIME (Seconds) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 6/ Wind Farm Steady-State Model • Example Layout • Equivalent Model > Generator - Power Factor Range - Voltage Regulation > Transformer > Collector System © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 7/ Modeling a Wind Power Plant? • 38 WTGs • Feeders • 57 MW • Substation > 34.5kV Collector > 230kV Circuits to POI © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 8/ Equivalent Model for System Level Studies Point of Interconnection (POI) Bus High Side Bus (collector, e.g 34.5kV) P gen Vreg bus Substation Transformer For most systems of N machines, model an equivalent transformer and machine as N times one Represent entire farm capability in power factor range, voltage regulation, etc Q gen Vterm Substation transformers usually have FOA rating roughly equal to total MVA of WTGs © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 9/ Equivalent Model for Plant Application Studies Project Substation Point of Interconnection (POI) Bus High Side Bus (collector, e.g 34.5kV) For most systems of N machines, model an equivalent transformer and machine as N times one Terminal Bus P gen Collector Equivalent Impedance Vreg bus Substation Transformer Substation transformers usually have FOA rating roughly equal to total MVA of WTGs Substation collector bus may have additional shunt reactive compensation to augment machine var capability Unit Transformer Q gen Vterm Unit Transformers are normally 1.75 MVA, 5.8% leakage reactance delta-wye connected padmounts The collector system may cover several miles, and have different topologies Provide an approximate equivalent R & X Include charging, particularly for cable collector systems © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 10 / Multi-Plant Topology is Complex Typical Objectives: Grid • Avoid circulating reactive power between plants Connecting nodes Several Miles • Manage interconnection voltage Several Miles X1 Thermal Plant Voltage Regulator X2 Wind Plant Voltage Control PT1 PT2 Wind Plant Voltage Control Wind Plant Voltage Control WF1 WF2 Thermal Plant WF3 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 61 / Dynamic Models & Simulation Results Plant and WTG Electrical Control Slow Plant Level Voltage Regulator (WindCONTROL Emulation) Vreg + 1+ sTr Qgen Verror - + Kpv 1+ sTv QPOI 1+ sTlpqd Kqd + Qord 1+ sTc + ref qd Ipmx from wind turbine model from generator / converter model Doubly Fed + + Eq"cmd to generator / converter model XIQmin KQi Vref term s Iqmx + + KVi s Iqmn IPcmd to generator / converter model Vterm IQcmd to generator / converter model Converter Current Limit P,Q priority flag Full Converter Dynamic Braking Resistor KVi s Test Signal * Vterm Pelec - Full Converter Pord XIQmax Test Signal V Vref qd Doubly Fed Vterm Intermediate Turbine Level Reactive Power Regulator Vref reg Kiv s Fast Turbine Level Voltage Regulator Ipmx IPcmd Pdbr to wind turbine model * Ipmx is fixed for©the doubly fedElectric model, International, or calculated by current limit 2016 General Inc.theAllconverter rights reserved Not for distribution without permission function for the full converter model 63 / Plant and WTG Electrical Control Slow Plant Level Voltage Regulator (WindCONTROL Emulation) Vreg + 1+ sTr Qgen Verror - + Kpv 1+ sTv QPOI 1+ sTlpqd Kqd + Qord 1+ sTc + ref qd Ipmx from wind turbine model from generator / converter model Doubly Fed + + Eq"cmd to generator / converter model XIQmin KQi Vref term s Iqmx + + KVi s Iqmn IPcmd to generator / converter model Vterm IQcmd to generator / converter model Converter Current Limit P,Q priority flag Full Converter Dynamic Braking Resistor KVi s Test Signal * Vterm Pelec - Full Converter Pord XIQmax Test Signal V Vref qd Doubly Fed Vterm Intermediate Turbine Level Reactive Power Regulator Vref reg Kiv s Fast Turbine Level Voltage Regulator Ipmx IPcmd Pdbr to wind turbine model * Ipmx is fixed for©the doubly fedElectric model, International, or calculated by current limit 2016 General Inc.theAllconverter rights reserved Not for distribution without permission function for the full converter model 64 / Plant and WTG Electrical Control Slow Plant Level Voltage Regulator (WindCONTROL Emulation) Vreg + 1+ sTr Qgen Verror - + Kpv 1+ sTv QPOI 1+ sTlpqd Kqd + Qord 1+ sTc + ref qd Ipmx from wind turbine model from generator / converter model Doubly Fed + + Eq"cmd to generator / converter model XIQmin KQi Vref term s Iqmx + + KVi s Iqmn IPcmd to generator / converter model Vterm IQcmd to generator / converter model Converter Current Limit P,Q priority flag Full Converter Dynamic Braking Resistor KVi s Test Signal * Vterm Pelec - Full Converter Pord XIQmax Test Signal V Vref qd Doubly Fed Vterm Intermediate Turbine Level Reactive Power Regulator Vref reg Kiv s Fast Turbine Level Voltage Regulator Ipmx IPcmd Pdbr to wind turbine model * Ipmx is fixed for©the doubly fedElectric model, International, or calculated by current limit 2016 General Inc.theAllconverter rights reserved Not for distribution without permission function for the full converter model 65 / Response of One Plant to a major line outage Reactive Power Output Point-of-regulation Voltage Terminal Voltage Behavior © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 66 / Wind Plant Droops Field and Tuned Gains Wind Plant Droop % (on plant MVAr base) Proportional Gain Integral Gain Plant 6.0 1.5 Plants 1.3 1.5 0.5 Plants 1.3 3.5 0.83 Plant 2.0 0.18 0.09 Plant 1.3 1.5 0.5 Plant 1.5 0.4 0.2 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 67 / Field test results Voltage Behavior – Uncoordinated Wind Plants Voltage Limit overrides power factor control System Grid capacitor conditions switching moving System conditions moving © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 69 / Voltage Behavior – Coordinated Wind Plants System conditions moving System Grid capacitor conditions switching moving © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 70 / Dynamic Behavior and Field Validation of Simulation Model No Droop - Simulation © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 72 / No Droop – Field Measurement © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 73 / With Droop - Simulation © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 74 / With Droop – Field Measurement © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 75 / [...]... rotor F rotor P conv F network Full Converter (FC) WTG Wind Turbine Wind Turbine Wound Rotor Wound Rotor Induction Generator Induction Generator Converter Converter Converter P stator  AC Winding Wind Turbine Q Pnet= Pstator Q net f stator stator fnet f stator net P stator frotor DC Winding P rotor Collector System (e.g 34.5kV bus) E fd … and Solar PV © 2016 General Electric International, Inc All... rights reserved Not for distribution without permission 35 / Why Model Validation? • Good models of wind plants are more important as wind penetration increases • Development of stability models is on-going > > Grid codes are driving increased functionality in wind plants Continuously evolving equipment and models create on-going need for validation How? • More detailed models (e.g., EMTP based) • Factory... / FC Electrical Control (WTG and PV Solar) Vref WindCONTROL Emulation Option for user-written model Qcmd Qref PFAref Power Factor Regulator IQcmd Reactive Power Control (to generator model) Qgen Vterm Converter Current Limit Functions Electrical Controller IPcmd (to generator model) Pord (from wind turbine model) Pelec (from generator model) P,Q Priority Flag Pdbr (to wind turbine model) Dynamic Braking... + Iqmx Vmax - KQi / s + s0 Vterm IQcmd Vref KVi / s - Converter Current Limit Porx Pord to Wind Generator Model Iqmn Vmin P,Q Priority Flag (efd) s1 Ipmx (vsig) IPcmd (ladifd) from Wind Turbine Model to Wind Generator Model Vterm Pelec from Wind Generator Model - 1 + + Pdlt Pdbr (elimt) - 0 Eerr Kdbr 0 to Wind Turbine Model + - 1/s Edbr s7 EBST Dynamic Braking Resistor © 2016 General Electric International,... / WTG and Solar Dynamic Models • WTG Overview • Model Structure  Generator/Converter with Voltage Protection  Electrical Control  Turbine and Turbine Control (for WTG)  Wind Power (or Irradiance) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 15 / GE WTG Dynamic Models Doubly Fed Asynchronous (DFG) WTG P net P net Q net Q net 3  AC Windings... XIQmin (efd) To Generator Model Auxiliary Test Signal ( model[@index].sigval[0] ) Pord (vsig) From Wind Turbine Model IPmax IPcmd (ladifd) Vterm © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 25 / DFG Turbine and Turbine Control Pdbr +  + Wind Speed Wind Power Model Blade Pitch Pmech Pelec (from generator model) (from electrical control model)... Active Power Control (optional) Trip Signal (to generator model) + WindINERTIA Control (optional) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission +  Pord (to electrical control model) 26 / DFG Turbine and Turbine Control From ewtgfc (elimt) +  From Pelec getwg (pelec) Wind Speed (glimv) Wind Power Model Pmech   s6  d  /dt max max &  cmd s0  min... rotor © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 28 / Full Converter (FC) Generator/Converter Current commands from Electrical Control Representation of fast regulator/PLL action similar to DFG Applies to Full Converter WTG and PV Solar Was 1/X” for DFAG IQcmd Isorc 1 1+ 0.02s (efd) From ewtgfc High Voltage Reactive Current Management -1 s0... reserved Not for distribution without permission 16 / PSLF WTG Dynamic Model Structure V reg bus V term Trip Signal Ip (P) Command P elec Electrical Control Model Generator/ Converter Model Qelec P gen , Q gen E" or I Q (Q) Command Power Order Wind Profile Model (User-written) Wind Speed P dbr P elec Turbine & Turbine Control Model F term © 2016 General Electric International, Inc All rights reserved... Protection Recommended PSLF and PSS/e ZVRT Setpoints Zero Voltage Ride Through vs GE ZVRT(Nov 20 08) & HVRT Specs Voltage at Point of Interconnection (Percent) 140 120 100 80 PSLF 60 40 GE ZVRT 20 0 -1.0 0.0 200 ms 1.0 2.0 3.0 4.0 5.0 6.0 Time (seconds) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 20 / DFG Generator Protection • Over and under-voltage ... non-standard functions (called “user-written models”), e.g HVDC, special relays, and some wind turbine generators…) 5) Data to drive calculations, standard models, user-written models and ‘events’... Converter P stator  AC Winding Wind Turbine Q Pnet= Pstator Q net f stator stator fnet f stator net P stator frotor DC Winding P rotor Collector System (e.g 34.5kV bus) E fd … and Solar PV © 2016 General... International, Inc All rights reserved Not for distribution without permission 7/ Modeling a Wind Power Plant? • 38 WTGs • Feeders • 57 MW • Substation > 34.5kV Collector > 230kV Circuits to POI