树型分支配电网的行波故障定位方法研究

Study on Traveling Wave Fault Location for Tree-Type Distribution Network

针对配电系统中树型网络故障分支的选择测距困难、准确度偏低的问题,提出一种基于小波变换的三端行波故障测距方法。该方法可以判断零序电压初始行波到达测量点的有效时间,利用时间差与线路长度、分支点位置的关系,对树型网络单相接地故障进行选线定位。该方法在分支点附近不存在死区,且不受波速度,故障角度,接地电阻等因素的影响,即使在测距装置故障、启动失灵或记录错误时间后仍能可靠定位。利用Matlab建立简单树型网络模型进行仿真,仿真结果表明,该方法可以快速准确地选出故障分支,精确定位,有助于进一步提高树型网络行波故障定位的可靠性。

Considering the deficiency of location faults on tree-type distribution network, a new method based on wavelet transform is presented. In this paper, using the relationship between time difference and distance difference, the position of branch point, the fault circuit is firstly identified by the information of the initial zero sequence voltage transient traveling waves, and then the fault location is solved. This method does not have a dead area when fault occurs near the branch point, and is not affected by the speed of current transient, fault phase angle and grounding resistance. Its accuracy is not affected when one individual or more location equipment break down, fail in startup, or record wrong arrival time of initial traveling wave. In this paper, the Matlab simulation results of simple tree-type network model show that this proposed method can filter the fault branch accurately and quickly, measure fault distance precisely. It is helpful to improve the reliability of traveling wave fault location for tree-type distribution network.