An Improved Single-Phase Fault Line Selection Method for Non-effectively Grounded System Based on Transient Energy

Abstract

AbstractThe domestic distribution network is mainly non-effectively grounded system, single-phase grounding fault accounts for more than 80% of the total number of faults, the fault characteristics are not obvious and easy to be affected by noise signals, at the same time, the polarity of zero sequence voltage and current transformer is unknown or reverse connection often occurs, which makes the local fault identification and line selection more difficult, and directly affects the fault response speed and disposal efficiency. In this paper, an improved single-phase to ground fault line selection method based on transient energy is proposed. By using the energy matching degree of transient zero mode current in each interval and the polarity relationship between transient zero mode current and steady-state zero sequence current in this interval, the existing fault line selection methods are easy to be affected by the polarity of external mutual inductors, and the polarity of mutual inductors can’t be checked online in the fault process. The physical concept of the method is clear, and the criterion threshold is not affected by the grounding mode and fault location of the system. RTDS simulation experiment and field engineering application verify the effectiveness and universality of the proposed fault line selection method.KeywordsTransient energyRTDSPolarityCheck