A new principle of faulty feeder detection for non-effectively earthed network using dominant transient frequency current

The fact of a dominant resonance frequency existed in the transient process of short-circuit fault is discovered by analyzing transient characteristics of single-phase earthed fault. 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. Dominant transient frequency(DTF) zero modal current in faulty feeder is 90deg lagging behind zero modal voltage of bus bar, while for healthy feeder it is 90deg leading zero modal voltage of bus bar. A novel detection principle based on Prony algorithm is presented in the paper, which determines the faulty feeder by comparing the magnitude of DTF current of faulty feeder and healthy feeder. It is verified by ATP simulation data and field measured fault data respectively.