A novel single-phase earth fault detection method using DTF current phase

A dominant resonance frequency is discovered in the transient process of single-phase earthed fault based on Prony algorithm. At this frequency, the magnitude of zero modal current in faulty feeder is much larger than that in healthy feeder, and their phase is approximately opposite. A novel selection method of single-phase earthed fault based on Prony algorithm is presented in the paper, which determines the faulty feeder by comparing the phase of Dominant transient frequency (DTF) current of faulty feeder and healthy feeder. That is, if the phase of a feeder is opposite to that of any other feeder, and then this feeder is selected as faulty feeder; if there is no obvious phase difference among all feeders, the fault point is on the bus bar. It is verified by ATP simulation data and field measured fault data respectively.