基于小波分析的中性点非有效接地系统故障选线方法研究

Research on fault line selection method for neutral point non-effective grounding system based on wavelet analysis

接地系统故障的存在对煤矿电网运行安全及质量带来安全隐患。分析了小波包变换原理、综合模值差系数确定、综合相关系数确定等相关小波分析理论;讨论了故障选线方法;通过ATP-EMTP软件对煤矿电网接地系统故障选线进行了分析。结果表明,运用db5小波分解方法能够对各类频段特征的系统线路故障进行识别,特别是当单相接地故障出现在母线时,可以快速准确地得出选线结果;当馈线回路数较多时,该方法具有较高的可靠性。

In the operation of the distribution network, the existence of the grounding system fault brings hidden trouble to the operation safety and quality of the power network. Firstly,the theory of wavelet packet transform,the determination of the value difference coeffi-cient and the determination of the correlation coefficient were analyzed. Then the fault line selection method was discussed. Finally,the fault line selection was analyzed by ATP-EMTP software. The results show that the db5 wavelet decomposition method can be used to i-dentify the system line faults of all kinds of frequency bands. Especially when the single-phase earth fault occurs in the bus,this method can quickly and accurately draw the line selection results. The method has high reliability when the number of feeder circuit is relatively large.