中性点不接地系统单相经过渡电阻接地故障特性分析

The Characteristic Analysis of Single Phase to Earth Fault with Transition Resistance in Neutral Unearthed System

为了提高供电可靠性,降低投入成本,我国配电网大部分采用中性点非有效接地系统运行。根据以往的统计分析,单相接地故障占了大多数。本文分析了在中性点不接地系统中,系统单相接地故障,在过渡电阻存在时,利用对称分量法,计算单相短路接地故障时的各相电压,并作出故障后各相电压随过渡电阻的变化曲线,指出故障相的电压并不一定最大。最后用MATLAB仿真证明。

In order to improve the reliability of power supply and to rdeuce operationg costs, most of power distri- bution network is neutral point non-effectively grounded.Based on past statistics, most of the fault is single-phase earth fault. The article analyzes single phase to earth fault with transition resistance in neutral unearthed system.It calculates the fault voltage with method of symmet- rical components and makes the Voltage curve with the transition resistance change.At last,it uses MATLAB to simulate that the fault phase voltage is not the lowest.