Abstract: To solve the problem of distribution network fault line selection caused by too few frequency components and no high amplitude low frequency components in the characteristic frequency band of transient zero sequence current, an improved ensemble empirical mode decomposition (MEEMD) method is proposed. Firstly, the influence of distributed generation on line zero sequence current was considered; then, the zero sequence current after fault was decomposed into multiple frequency signals according to frequency by meemd, and the eigenmode function was obtained and the highest frequency component is extracted; finally, the line selection result was obtained by analyzing the signal waveform of the highest frequency. The basic signal was not needed in this process, so the characteristics of the obtained signal were closer to the original signal. The process of fault line selection based on meemd was described in detail, and the influence of multi scene distribution network considering distributed generation on fault line selection is discussed. The simulation results show that the method can effectively improve the accuracy of fault line selection.

Key words: Fault line selection, Zero?sequence current, Distributed generation, MEEMD, Ground fault

摘要： 针对暂态零序电流特征频段内含有过少的频率分量以及无较高幅值的低频分量而给配电网故障选线带来的困扰，利用改进的集合经验模态分解（MEEMD）方法解决选线准确率低的问题。首先，考虑配电网引入分布式电源后对线路零序电流的影响；然后，利用MEEMD将故障后的零序电流按照频率大小分解成多个频率信号，得到本征模态函数并提取其最高频成分；最后，通过分析最高频率的信号波形得出选线结果。该过程不需要基信号，从而使得到的信号特性更接近原信号。结果表明，该方法可有效提高故障选线的准确率。

关键词: 故障选线, 零序电流, 分布式电源, 改进的集合经验模态分解, 接地故障