基于小波包的配电网单相接地故障选线新方法

Novel Algorithm of Fault Line Selection Based on wavelet Packet for Single-Phase to Ground Fault in Distribution Networks

应用小波包分析提出了一种基于“故障-能量”诊断模式的配电网单相接地故障选线新方法,它根据被分析信号的特征合理选取小波基和频带宽度,应用低频带信号的小波包分解系数能量与重构系数能量比值的偏差模,构成故障选线判据。该方法适用于5%～10%补偿度的各种结构配电网,不受线路长度和短路时刻的影响,抗电弧过渡电阻能力强。考虑不同短路时刻、不同接地电弧电阻、不同线路长度、不同补偿度等多个因素,对配电网小电流接地系统的单相接地故障进行了大量仿真,仿真结果证明了该算法的有效性、正确性。

A novel method of line-to ground fault line selection is proposed based on fault-energy by wavelet packet analysis. A lot of line-to-ground faults are completed by simulation for distribution networks at different time with different analyzed signals. The characteristic of line-to-ground fault is obtained by wavelet analysis, while the structure of distribution network is different with sub-network or without sub-network, and while the percentage of compensation is changed from 5% to 10% in distribution networks. Then a criterion of line-to-ground fault line selection is built by the deviation modulus of the ration of decomposition coefficient energy to reconfiguration coefficient energy. This new criterion is exact to select fault line at any time of short circuit with high value arc-resistance, and it is used to locate any line with different lengths. Simulations show that the novel algorithm of fault line selection is correct and effective.