小波重构算法在配电网接地选线中的应用

APPLICATION OF WAVELET RECONSTRUCTION ALGORITHM IN PHASE-TO-GROUND FAULT DETECTION OF DISTRIBUTION NETWORKS

当配电网单相接地故障发生在相电压过零点附近时,故障线路零序电流中含有大量的暂态感应电流直流分量。文章提出了利用小波的分频特性和重构算法,分别求取各线路零序电流中直流分量和基频分量的重构信号,根据故障线路和非故障线路零序电流中二者的能量比的不同,来确定故障线路的方法。应用电磁暂态程序(ATP)仿真也表明,用该方法实现配电网相电压过零点附近发生故障的故障选线,具有较高的灵敏度和可靠性。

If single-phase to earth fault of distribution network occurs when the phase voltage is near zero, there are lots of transient decay induced current components contained in zero sequence current of faulty line. Based on this phenomenon, a new method of faulty line detection is proposed, in which the wavelet with advantage of frequency decomposition and signal reconstruction are used to analyze the reconstructive signals of the decay current and fundamental current in zero sequence current of each line. Because the energy ratio of these two reconstructive signals in faulty line is different from which in normal line, the faulty line can be found out. Lots of ATP simulation results show that the proposed method can exactly and reliably detect the faulty line occuring fault when phase voltage is near zero.