基于形态学和广义S变换的小电流接地故障选线方法

摘要

提出基于数学形态学和广义 S 变换相结合的小电流单相接地故障选线新方法。数学形态学为一种新型的非线性滤波技术，考虑电力系统的信号特点，选取一种直线型结构元素，滤波时既能消除毛刺状噪声，又能很好地保持信号的形状；广义 S 变换克服了 S 变换中基本小波基固定的缺点，有更好的时频分辨率。首先对信号进行数学形态方法滤波预处理，利用对处理后的故障信号进行广义 S 变换分析得到模时频矩阵，最后对得到的模时频矩阵特征量进行能量分析，选择出故障线路。仿真结果表明，该方法可以在不同工况的情况下准确地进行配电网故障选线。%A method of current single-phase fault line selection based on mathematical morphology and generalized S-transform is proposed. Mathematical morphology is a novel nonlinear filtering technique. Considering the signal characteristics of the power system,a linear structural element is selected. Not only can eliminate the burr shape noise,but also maintain the shape of the signal well. Generalized S-transform overcomes the shortcomings of the basic wavelet bases fixed in the S transform,and has a better frequency resolution. The signal was filtered by the mathematical morphological first. Then the generalized S-transform is used to analyze fault signals to get the modulus frequency matrix. Finally the energy characteristics modulus frequency matrix is analyzed to select the fault line. Simulation results show that the method could select fault line accurately under different working conditions of distribution network.