A Generalized Morphological Transform Based Faulty Feeder Selector Suitable for the Non-Effectively Grounded Power Systems

Single phase-to-ground faults are the most frequent faults likely to occur in power distribution networks. The fault current of the faulty feeder is quite low when a single-phase earth fault occurs on a neutral non-effectively grounded grid. As for the safety of the system, such faults should be quickly distinguished and the faulty feeder should be correctly selected as well. This paper analyses the characteristic of the zero-sequence transient currents of a neutral non-effectively grounded system when a single phase-to-ground fault occurs. The generalized morphological transform is designed to form the new method for fault feeder selecting, which combines the excellent singularity detecting together with the noise-repressing abilities of mathematical morphology filter. The results of simulation using ATP and Matlab demonstrate that this method is immune to the variation of network structures and parameters. It also has the ability of enduring high fault path resistance.