基于EMD分解的直流牵引供电系统短路故障识别

摘要

It is essential to identify short-circuit current mode characteristics of the DC traction power supply system accurately in its relay protection. Oscillation current of DC traction power supply system can lead di/dt-△I protection and feeder switch to make mistakes. In terms of the differences in the modes of oscillation current and short circuit current, the shock current finite number of intrinsic mode functions (IMF) and its margin can be achieved by using the empirical mode decomposition (EMD). Taking the margin slope as features, the operating status can be diagnosed correctly. The simulation results show that this method, cooperating with di/dt - △I protection, can identify DC traction power supply system short-circuit fault accurately.%准确识别牵引供电系统故障电流的信号特征是实现直流牵引供电系统继电保护的基础,直流牵引负荷的电流振荡会使得di/dt-△I保护做出错误故障判断从而引起馈线开关误动.根据振荡电流与短路电流模态上的差异,采用经验模态分解(EMD)可获得振荡电流的有限个固有模态函数(IMF)及其余量,以余量斜率作为特征量可正确判断运行状态.仿真结果表明,此方式配合di/dt-△I保护即可实现直流牵引供电系统短路故障的准确识别.