Impact of DFIG windfarms and instrument transformers on transient based protection

The impact of wind generation on high frequency, transient-based overhead line protection is investigated. An 8 bus section of the 132 kV Scottish network with a realistic DFIG-based wind farm model is simulated on a real time digital simulator. Short circuit studies are conducted on a double circuit overhead line adjacent to the wind farm. Three case studies are compared: the DFIG model, a model with instrument transducers and the control model. Analysis is conducted on frequency and time domain voltage and current waveforms measured at the wind farm bus. These show that, compared with the control case, the impact of each case is slight, but the CVT attenuates the higher frequencies of the voltage waveforms slightly more than the DFIG case.