Time-domain fault line selection based on correlation analysis in neutral indirect ground system

Fault line selection is an important issue in protection technique research for distribution network with neutral indirect ground system.By analyzing zero-sequence currents and zero-sequence bus voltage in equivalent zero-sequence network,this paper presents a new fault-selection method,which compares the correlation coefficients between the zero-sequence bus voltage and zero-sequence currents of different feeder to determine the fault line.Theoretical analysis and simulations show the validity of the new method.The method can select fault line successfully with different fault condition,including different initial fault angle,different transition resistance,different fault position,and can be used in feeder protection because of its bootstrap characteristic.