基于小波包变换的地铁远方短路电流分析

本文讨论了地铁直流侧远方短路故障的三种保护方案 ,指出现有的基于电流变化率方法以及基于傅立叶变换的方法都难以躲开机车起动电流。文中根据远方短路故障电流受铁轨集肤效应的影响而具有不断变化的时间常数的特点 ,提出使用Haar小波包变换来提取该短路电流的暂态特征的新方法 ,仿真结果表明该方法可有效避开机车起动电流

The Analyzing of Distant Short-Circuit Fault Current in Rapid Transit Systems Based on Wavelet Packet Transform

This paper discusses three distant short-circuit protections for the rapid transit systems, and points out that or the Fourier transform cannot always distinguish between distant faults and train starting currents. Based on the characterization that the time constants of the distant short-circuit fault currents exhibit a time varying due to the skin effect of the track, a novel method using Haar wavelet packet transform is proposed in this paper. The simulation results show that the wavelet packet transform can give a good discrimination between the distant fault current and the train starting current.