基于小波包及相关分析的故障选线方法

A Method for Fault line Selection Based on Wavelet Packets and Correlation Analysis

分析小电流接地系统故障选线的现状及稳态选线方法的优缺点,仔细研究配网单项接地故障特征后研究用暂态电容电流进行选线,判据如下:先将暂态电压信号利用小波包变换进行分解,得到的能量最大值所对应的即为特征频带,再将各零序电流在特征频带逐一分解,将各条线路得到的小波系数组成相关性矩阵,将矩阵中的元素取平均值得到各条线路与其他线路的平均互相关系数,数值最小者对应的为故障线路。判断过程简洁明了,抗干扰能力强,不受中性点接地方式、电网结构等的影响,能够适应小电流接地系统中多种故障模式,并且用MATLAB/WAVELET仿真验证了本判据的可行性和正确性。

This paper analyses the development of fault Line selection and the advantages and disadvantages of the steady-state line selection. After careful study of the distribution network single earth fault characteristic,points out that we can select fault I.ine with. transient capacitive current. An Improvement is raised on tb.e basis of the current research methods： convert transient voltage signal thought wavelet packet transform , characterized in band is get by the maximum, the zero-sequence current is decomposed in each of the characteristic band, form correlation matrix by Wavelet coefficients of each line, average matrix elements to get the mutual relationship number of the lines, the smallest is the fault line. The judging process is simple, strong anti interference and is not affected with neutral grounding mode and the grid structure. The theoretical analysis and MATLAB simulations show that the proposed method can choose the faulty line exactly and reliably under all kinds of fault conditions.