基于分区所电抗的电气化铁路故障测距方案

Fault Location Scheme for Electric Railway Based on Reactance Measured at Section Post

研究目的:在我国传统普速电气化铁路中,牵引网主要采用直接供电方式,并且绝大部分为复线运行模式。当供电牵引网发生故障的时候,一般配置专用的故障测距装置,主要采用电抗法、电流比或电抗比法进行故障测距。随着变电所综合自动化系统的广泛应用,新建变电所逐渐取消了故障测距装置,测距功能由微机保护装置采用电抗法完成。但在复线运行情况下发生故障的时候,电抗法常常出现测距不准的现象。本文通过分析测距不准的原因,提出一种新型的基于分区所电抗的故障测距原理,并基于Matlab/Simulink进行仿真分析,以期能适应电气化跌路故障测距的需要。研究结论:(1)变电所测量电抗在单线故障、复线故障时具有不同表现形式,证明了基于变电所馈线保护装置测量电抗的测距原理的缺陷;(2)推导并仿真验证了电气化铁路复线运行、"V停反行"时牵引网发生故障,分区所测量电抗的公式,验证了二者的一致性;(3)测距原理不受运行模式、过渡电阻的影响;(4)该测距方案可以作为当前复线电气化铁路牵引变电所缺乏专用测距装置情况下的一个重要参考和补充。

Research purposes： In the traditional common return traction power supply and majority of them run on speed railway in China, the main power supply mode is track - double track line. When fault occurs on traction power supply system, fault location is usually completed by specialized fault locator. The fault location methods mainly include reactance, ratio of currents and ratio of reactance. With the wide application of substation automation system, fault locator is canceled in new substation and the function of fault location is completed by microcomputer - based relay by using reactance method. But, when fault occurs in power supply system with double track line, the result of fault location is not accurate by using reactance method. What result in inaccuracy of fault location is analyzed in this paper and a new fault location scheme based on reactance measured in section post is proposed. The simulation based on Matlab/Simulink shows that this new scheme matches with the location requirement in electric railway, and this scheme is not influenced by the power supply system with double track line and fault transitional resistance. Research conclusions： （ 1 ） The measured reactance at substation is different in single track fault and double track fault. The deficiency of locating theory based on measured reactance of feed line relay protection device at substation is testified. （2） The measured reactance at section post is deduced when fault happening in double track and ＇V＇ shape power supply mode. The measured reactance is same in these two situations, which is testified by the simulation. （3） The fault locating scheme is not affected by the running mode and transient resistance. （4）The novel fault locating scheme is an important reference and supplement when dedicated fault locator is not equipped at substation on double track line in electric railway.