基于PSCAD的牵引供电系统建模与短路电流仿真

在地铁牵引供电系统馈线保护方式中，电流变化率及电流增量保护是地铁供电系统中常用的保护方式。然而从地铁故障录波得到的众多故障波形看，故障电流常存在幅值很高的冲击电流而后振荡衰减的特点。电流变化率及电流增量保护方式假设的故障电流按指数规律变化的特点与史际情况有出入。笔者基于PSCAD对供电系统进行建模，分析了整流器对短路电流中暂态电流冲击的影响，考虑到实际电器短路瞬间漏抗增大，对PSCAD中的实际电器做了--一定的改进，最后得到的仿真波肜与实际短路电流波肜十分吻合。对基于电流变化量原理的保护研究以及误动作的排除及其相关问题的研究具有卜分重要的意义。

Modeling of Traction Power Supply System Based on PSCAD and Simulation of Short Current

In the feeder protection modes of subway traction power supply system,the current change rate protection and current increment protection are used commonly.However,by detecting the recorded fault waveforms,the characteristics of fault current is found to be that the current would decay oscillatorily after an impulse current with high amplitude.So the hypothesis in the modes of current change rate protection and current increment protection that the fault current changes exponentially deviates from the actual situation.In this study,the model of electricity supply system is constructed based on PSCAD,the influence of rectifier on the transient current impulse in short-circuit is analyzed,and the actual electric apparatus in PSCAD is improved after considering the transient increment of leakage in short circuit,finally the obtained simulation waveforms are consistent with those of actual short-circuit current.This work is important for the protection study based on the principle of current change amount and for the relevant researches on malfunction exclusion.