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WGR Equivalent Modeling Keith Smith Network Model Engineer RARF Workshop III August 29, 2013. WGR Equivalent Model. System Protection Model Equivalent Aggregated turbines modeled at .69 kV Turbine step-up transformers aggregated into one .69-34.5 kV transformer
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WGR Equivalent Modeling Keith Smith Network Model Engineer RARF Workshop III August 29, 2013
WGR Equivalent Model • 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
Equivalent Methodology • 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
Generator Data • Required turbine data for system protection cases
Current Limits • Required for type 3 and type 4 turbines