基于并联电阻扰动信号的配电网故障定位方法分析

基于并联电阻扰动信号的配电网故障定位方法利用对外加扰动信号的追踪来实现定位,已在配电网故障定位中较为广泛应用。但该方法在实际应用中会出现施加扰动信号后故障特征变化规律不确定的问题,使得故障定位装置误判,导致故障定位失败。为此,文中建立了小电流接地系统等值电路,深入研究了扰动信号通过不同非故障相注入后单相接地故障电流的变化规律,分析了负荷电流以及接地过渡电阻的影响,对基于并联电阻扰动信号的配电网故障定位方法的有效性进行理论论证。提出了对中性点不接地系统或经欠补偿消弧线圈接地系统扰动信号应通过故障相的滞后相注入,对中性点经过补偿消弧线圈接地系统扰动信号应通过故障相的超前相注入的优化方法。仿真结果证明了所提优化方法的有效性。

Analysis on Distribution Network Fault Location Method Based on Parallel Resistance Disturbed Signal Injection

The distribution network fault location based on parallel resistance disturbed signal injection is realized by tracking and diagnosing the disturbed signal. It has been widely used in distribution network fault location. However, in practical application, this method has the problem of uncertainty characteristics of the current variation, which causes the fault location device to misjudge. Therefore, this paper establishes the equivalent circuit of the small current grounding system, deeply studies the variation of the fault current after the disturbed signal injected through different non-faulty phases, and analyzes the influence of the load current and the grounding transition resistance. The theory of the effective fault location technology based on parallel resistance disturbed signal is demonstrated. It is proposed that the disturbed signal should be injected through the lagging phase of the fault phase in the ungrounded neutral sysytem or undercompensated arc-supperssion-coil-ground neutral system. The disturbed signal should be injected through the ahead phase of the fault phase in the overcompensated arc-suppression-coil-ground neutral system. The simulation results prove the correctness of the optimization method.