1. WGR Equivalent Modeling Keith Smith Network Model Engineer RARF Workshop III August 29, 2013

2. 2 System Protection Model Equivalent –Aggregated turbines modeled at.69 kV –Turbine step-up transformers aggregated into one.69-34.5 kV transformer –Collector system represented as single line –Provides more accurate fault data than aggregate turbine modeled at 34.5 kV level –Grounded Wye-Delta connection very common for turbine step-up transformers, limits single line to ground fault current contributions from turbine WGR Equivalent Model

3. 3 Calculating impedances for equivalent model –Equivalent turbine impedance calculated as N turbines in parallel –Equivalent transformer impedance calculated as N transformers in parallel –Equivalent collector system impedance calculated from collector system cable data using the following equation: –Where n = number of turbines feeding cable segment N = number of total turbines Equivalent Methodology

4. 4 3-Phase to Ground Fault Full System

5. 5 3-Phase to Ground Fault Equivalent

6. 6 Single Line to Ground Fault Full System

7. 7 Single Line to Ground Fault Equivalent

8. 8 Collector System Example

9. 9 Collector System RARF Format GENERATOR DETAILSCable TypeWIND SEGMENT DETAILS Resource Name (Unit Code/Mnemonic)Cable TypeFromToCircuit Number Voltage Level Cable Segment Length Number of Turbines On Cable Segment List alpha/numeric kVin kftInteger WIND_FARM1000 kcmil0121134.52.9559 WIND_FARM1/0 AWG12118134.5.081 WIND_FARM1000 kcmil121111134.53.2058 WIND_FARM1/0 AWG11112134.52.862 WIND_FARM1/0 AWG1211134.51.3051 WIND_FARM500 kcmil11117134.54.056 WIND_FARM500 kcmil1716134.51.1055 WIND_FARM4/0 AWG1615134.51.044 WIND_FARM1/0 AWG1514134.51.1553 WIND_FARM1/0 AWG1413134.5.942 WIND_FARM1/0 AWG1310134.52.0401 WIND_FARM1000 kcmil0211234.511.0959 GENERATOR DETAILS COLLECTION SYSTEM DETAILED MODELPOSITIVE SEQUENCE DATAZERO SEQUENCE DATA Resource Name (Unit Code/Mnemonic)Cable Type Voltage Level kVR/kftX/kftCharging Bc/kftR0/kftX0/kft List kV(p.u. on 100 MVA base) WIND_FARM1000 kcmil34.50.0020163830.0031842054.115E-070.0125351820.004444444 WIND_FARM500 kcmil34.50.0036546940.0035034663.161E-070.0200378070.009090527 WIND_FARM4/0 AWG34.50.0084772110.0040159632.361E-070.0263474060.011048099 WIND_FARM1/0 AWG34.50.0165931530.0045536651.595E-070.0384793110.018239866

10. 10 Generator Data Required turbine data for system protection cases

11. 11 Current Limits Required for type 3 and type 4 turbines

12. 12 QUESTIONS?