小波法识别配电网线路高阻故障

Identification of High Resistance Fault in Distribution Network by Wavelet Method

配电网中最常见的一类故障属于单相接地故障。当故障发生时,能够快速识别故障所在位置以及用最快的速度切除故障时保证系统安全运行的重要保障。单相高阻接地是电路接地故障中最常见的一类故障,然而高阻故障时电流和电压的突变量与正常情况下的单相接地故障相比是小很多,现有的保护装置很难识别出电气量的突变从而无法可靠的作出保护。本文利用PSCAD仿真软件构造配电网模型,提取故障时的零序电流和零序电压两个暂态量,通过小波变换分析法对其进行分解、重构,得出零序电流和零序电压的细节系数后代入特征值方程求出各段母线和不同支路的特征值,通过比较判断出故障所在线路。

One of the most common faults in distribution network is single phase to ground fault.When the fault occurs,it can quickly identify the location of the fault and ensure the safe operation of the system when the fault is removed with the fastest speed.Single phase high impedance grounding circuit is a kind of the most common fault grounding faults,however high resistance fault single-phase variable current and voltage and normally grounding fault is small compared to many existing protection devices,it is difficult to identify the mutation of electrical quantities to make reliable protection.This paper uses PSCAD simulation software to construct the model of distribution network,the zero sequence current and zero sequence voltage fault when two transient analysis,through the wavelet transform decomposition and reconstruction of the law,the details of the coefficient of zero sequence current and zero sequence voltage by eigenvalue equations of each bus and different branches by comparing the feature value.Judge the faulty line.