Faulty feeder detection based on the composite factors in resonant grounding distribution system

Abstract

Faulty feeder detection of the single-phase-to-ground fault in resonant grounding distribution system (GRDS) is faced with huge challenge due to weak fault current, and the existing methods indicate low reliability in some situations. For improvement, a new method based on composite factors is proposed in this paper. The composite factor is composed of transient factor and steady-state factor which are defined respectively according to transient process and steady-state component in the fault zero-sequence equivalent network. The transient factor of faulty feeder is much greater than those of healthy feeders, and the steady-state factor of faulty feeder is a constant and also much larger than those of healthy feeders when the series resistance of Peterson coil exists. However, the steady-state factors of all feeders are equal to 0 when the series resistance is short-circuited. Thus, a threshold value is constructed. By comparing the composite factors and the setting threshold, the faulty feeder can be detected. The correctness and adaptability of the proposed method are verified by simulations under various fault situations, such as different transition resistances, fault initial angles, fault distances, Gaussian white noises and compensated degrees. The tested results of experiment platform based on RTDS prove the correctness and feasibility of the proposed method.