Non-fault Identification Based on External Injection before Interphase Fault Reclosing in Distribution Network with Shunt Capacitors

Abstract

The existing interphase fault auto-reclosure of distribution network has the risk of reclosing in permanent faults, it is necessary to identify the fault nature before three-phase reclosing. By using the more abundant electrical information after the injection of external voltage source, the varied characteristics of phase differences between voltage and current of interphase faults under different fault natures are analyzed for the 10kV distribution lines with shunt capacitors. The analysis shows that the circuit structure changes after the transient fault disappeared, and the phase difference between voltage and current becomes 90°, while the permanent fault circuit is stable with a phase difference of 120°. Therefore, using the phase differences between voltage and current before and after the fault disappearance, build a fault nature identification scheme. The results of simulation show that the proposed method can accurately identify the fault nature and is basically not affected by fault location and transition resistance which has good adaptability.