配电网单相接地故障快速选相方法研究

配电网单相接地故障传统判相方法需要考虑相序和电压大小来判别故障相,但高阻接地故障时相角测量较为困难,因此故障相判断难度很大。通过分析小电流接地系统发生单相接地故障时各相电压以及中性点电压随故障电阻变化的关系,提出单相接地故障时仅根据中性点电压大小以及相电压大小直接判断故障相的简化方法。最后通过PSCAD/EMTDC搭建仿真模型,仿真表明所提判相方法能在不同故障电阻的情况下准确判别出故障相。

Fault phase fast detection of the single-phase-to-ground fault in a power distribution network

In a power distribution network,the traditional single-phase-to-ground fault phase detection method needs to consider the phase sequence and amplitude of voltage to determine the fault phase.However,it is difficult to measure the phase angle in a high impedance grounded fault.As a result,it is more difficult to determine the fault phase.The relationship between the phase voltage and the neutral displacement voltage are analyzed when a single-phase grounded fault occurs in a small current grounded system.This paper proposes a simplified method to detect the fault phase directly and quickly according to the neutral displacement voltage and phase voltages.Finally,a simulation model is built in PSCAD/EMTDC,and the results show that the proposed method can accurately identify the fault phase in the case of different fault resistances.