国内大多数中低压配电网都采用中性点通过消弧线圈接地的方式运行，其故障类型主要以单相接地故障为主，大概占到了总体的80%。近年来，国内外专家对单相接地故障进行了深入研究，但是由于信号受到噪声、接地方式等各种因素的影响，造成系统不能进行有效可靠的故障选线，影响了电网的稳定运行。因此，本文对谐振接地系统单相接地故障选线问题展开研究，对中低压电网的安全稳定运行有着重大的意义和应用价值。主要工作如下： 首先，在查阅众多文献的基础上，对谐振接地系统深入分析。根据国内、外对单相接地故障的研究现状，总结出现阶段该领域的难点，对谐振接地系统单相接地故障的暂、稳特性分别进行全面细致的研究，得知暂态过程中信号特征比稳态强，且更容易精确提取并识别出故障，并以此为研究对象； 其次，重点通过小波变换检测故障线路以及小波包对采集信号的分析处理展开深入研究。根据小波变换检测可以选择出系统的故障相。在处理暂态信号时引入小波包算法，以小波包函数来分解重构零序电流信号。对于小波变换不能分解的高频信号，小波包算法可以进行分解，可为故障选线提供良好的信号处理工具。 最后，通过对多种选线方法优缺点进行对比，相关分析法只需分析信号波形之间的相似性，而不需要进行复杂的计算，因此用相关分析法作为谐振系统故障选线方法，因为原始信号受谐波、噪声等干扰程度比较大，不加处理直接利用相关分析法受信号影响较大，容易造成分析结果不准确。因此，提出基于小波变换检测和小波包分解的相关分析故障选线法。通过仿真和实验结果表明，本文所提算法在故障选线中是可行的。

Most of China's low-voltage power distribution networks use a neutral point to run through the arc suppression coil. The type of failure is mainly based on single-phase ground faults, accounting for about 80% of the total. In recent years, domestic and foreign experts have conducted in-depth research on single-phase ground faults, but due to noise, grounding and other factors, the system can not effectively and reliably select the fault line, which affects the stable operation of the grid. Therefore, the study of single-phase ground fault line selection in resonant grounding systems is of great significance and application value for the safe and stable operation of medium and low-voltage power grids. This article analyzes the problem of selecting a line for a resonant grounding system. The main tasks are as follows: First, on the basis of reviewing numerous documents, an in-depth analysis of the resonant grounding system is performed. According to the research status of single-phase grounding faults at home and abroad, the difficulty in this field is summarized, and the transient stability characteristics of single-phase grounding faults in resonant grounding systems have been studied comprehensively, and the signal characteristics in the transient process are known. It is stronger than steady state and it is easier to accurately extract and identify faults. Secondly, in-depth study is mainly focused on the analysis of faulty lines by wavelet transform and the analysis and processing of collected signals by wavelet packets. According to the wavelet transform detection, the fault phase of the system can be selected. In the processing of transient signals, the wavelet packet algorithm was introduced and Sym6 function was used to decompose the zero-sequence current signal. For high-frequency signals that can not be decomposed by wavelet transform, wavelet packet algorithm can be decomposed to provide a good signal processing tool for fault line selection. Finally, by comparing the advantages and disadvantages of multiple line selection methods, the correlation analysis method only needs to analyze the similarities between the signal wave forms without the need for complex calculations. Therefore, the correlation analysis method is used as the fault line selection method for the resonant system because The original signal is greatly affected by harmonics, noise, etc., and the direct use of correlation analysis without signal processing is greatly affected by the signal, which may easily lead to inaccurate analysis results. Therefore, a correlation analysis algorithm based on wavelet transform detection and wavelet packet decomposition is proposed. Simulation and experimental results show that the proposed algorithm is feasible in fault line selection.