（20期已排）基于聚类经验模态分解和差分熵的输电线路故障测距研究

为提高输电线路的故障测距精度,本文提出了一种基于聚类经验模态分解(EEMD)和差分熵(DE)的输电线路故障行波测距方法。首先利用改进的差分熵信号处理方法对输电线路电流进行熵值计算,通过与正常电流熵值的对比,判断电流是否发生突变。然后采用EEMD分解对发生突变的故障电流进行处理,有效去除故障信号中的噪声,避免模态混叠,获取准确反映故障信息的IMF分量。随后对分量实行差分熵方法中的差分分析,将电流的变化幅度进行有效量化,并建立每个信号点的变化程度与时间的对应关系,从而解决波头位置难以确定的问题,获得故障初始行波到达每个监测点的准确时间。最后利用行波双端法,实现输电线路的故障测距。仿真结果表明,该方法能够较好地解决故障测距时存在的信号噪声和波头测量时间不准确的问题,有效提高故障测距的精度。

Study on Fault Locating for Transmission Lines Based on EEMD and DE

In order to improve the fault location accuracy of transmission lines , a detection method based on the ensemble empirical mode decomposition algorithm(EEMD) and the difference-entropy(DE) for transmission lines fault locating is proposed. Firstly, the improved differential entropy signal processing method is used to calculate the entropy of the transmission line current. It can be judged that whether the current has mutated by comparing the entropy with the normal value. Secondly, the falut current is decomposed by EEMD, which can effectively eliminate the noise in the fault signal and avoid the aliasing of the mode. In this process, the multiple intrinsic mode functions(IMF) components that accurately reflects the fault information is obtained. And then, the magnitude of the current variation will be quantified by the differential analysis of the differential entropy method. Besides, the corresponding relation between the degree of change of each signal point and the time will also be established, so that the position of the wave head and the initial time of the fault initial wave arriving at each monitoring point can be determined. Finally, the fault location of transmission lines will be determined by using the double terminal method of traveling wave. The simulation results show that the method can be used to solve the problem of current signal noise and mode aliasing in fault location of transmission lines, which can effectively improve the accuracy of fault location.