中性点不接地系统单相经过渡电阻接地故障特性分析

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。

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

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.