基于EEMD和关联维数的小电流接地故障选线方法

针对小电流接地系统发生单相接地故障时,各线路零序电流的非平稳、非线性等复杂特性,提出一种基于总体模态分解(EEMD)和关联维数相结合的选线方法.EEMD算法是在经验模态分解(EMD)的基础上加以改进,能够消除模态混叠现象,同时保留了经验模态分解具有的良好的时频特性;EEMD能根据信号本身的特点对瞬时出现的信号进行分析,并将信号分解成若干个固有模态函数(IMF)分量和一个剩余分量.利用关联维数不易受噪声干扰特点,对分解的IMF信号分量进行处理,采用G-P算法计算关联维数,通过比较关联维数的大小选出发生故障的线路.仿真结果表明,该选线方法可靠性高且效果较好.

Selection Method of Small Current Grounding Fault Line Based on EEMD and Correlation Dimension

In order to solve the problems that the non-stationary and nonlinear of each line zero-sequence current when the single phase ground fault occurs in the small current grounding system,a line selection method based on the ensemble empirical mode decomposition (EEMD) and correlation dimension is proposed.EEMD algorithm is improved on the basis of the empirical mode decomposition (EMD),which can eliminate the mode aliasing,while retaining the good time-frequency characteristic of EMD.According to the signal itself features,EEMD can analyze the instantaneous signals,and decompose the signals into a several intrinsic mode function (IMF) components and a residual component.The correlation dimension is less susceptible to noise,which can be used to process the decomposed IMF signal component.The G-P algorithm is used to calculate the correlation dimension,and the faulty line is selected by comparing the size of the correlation dimension.The simulation results show that the proposed method has high reliability and good effect.