基于小波包分解的剩余电流接地故障选线方法

为解决电网发生单相接地故障后,无法对故障线路精确辨识的问题,提出了一种基于小波包分解的剩余电流接地故障智能感知方法。依据小波分析法和智能感知原理,针对接地故障产生的剩余电流进行故障信息采集,将收集到的剩余电流信息进行分析对比,以感知接地故障并进行故障识别;通过研究交流电源剩余电流在线式监测和基于小波变换方法的弧光接地故障诊断技术,利用小波包分解得到电流时频特性进行故障选线;分析故障线路和正常线路中电流特性的差异,并精确辨识出故障点;在仿真软件中对所提出的小波包分解基础上的故障线路选线方法进行了仿真。仿真结果表明,该方法能精确提取时频信息,有效确定故障线路。研究结果为站用交流电源接地故障选线方法提供了参考。

Residual current grounding fault intelligent sensing technology based on wavelet packet decomposition

In order to solve the problem that the fault line cannot be accurately identified after single-phase grounding fault occurs in power grid,an intelligent sensing method of residual current grounding fault based on wavelet packet decomposition was proposed.Based on wavelet analysis and intelligent sensing principle,the residual current generated by grounding fault was collected,and the collected residual current information was analyzed and compared to sense the grounding fault and identify the fault.By researching on-line monitoring of residual current of AC power supply and arc grounding fault diagnosis technology which is based on wavelet transform,the time-frequency characteristics of current obtained by wavelet packet decomposition were used for fault line selection;the fault line selection method based on the proposed wavelet packet decomposition was simulated.The results show that the time-frequency information can be extracted accurately and the fault line can be determined effectively by using the method,and the fault line can be accurately identified with the difference of current characteristics between fault line and normal line.The research result provides a reference for the design of intelligent sensing system of AC power grounding fault.