Behavior of different distance relay characteristic on lines fed from type-1 and type-2 WTGU connected radially to grid: A case study

Line protection in HV/EHV/UHV lines is primarily by distance protection due to its selective, reliable and secure operation. With the wind farm penetration, the SIRs of lines are going to change drastically throughout the day. A case study has been performed in this paper to study the behavior of dynamic characteristics with respect to these changes. Analytically fault voltages and currents are calculated for the system. Distance relay implemented on hardware has been validated with these waveforms and inferences have been made to give recommendations for characteristics to be applied in practical systems for secure and reliable operation of distance relay.