Influence Of Transformer Leakage Reactance On Fault Location Of High Speed Railway Traction Network

In today's increasingly development of high speed railway,it is particularly important to the reliability of power supply system of high-speed.Fault location is the important means of quickly locating fault and restoring it on power supply system of high-speed that can resume to normal operation.At present,China's large-scale use of high speed railway is parallel AT(Auto-transformer)operation mode,for the AT power supply system with parallel connections,the fault location method currently used mainly boosting currents ratio of ATs,currents ratio of up and dawn rail and currents ratio of cross line,for these three fault location theory,most of the literature were omitted transformer leakage reactance(including substation main transformer leakage resistance and AT leakage reactance)at the calculation of derivation and application at present,according to it,this paper is studied in the following ways:In order to simplified within the substation equipment,the substation of AT power supply system with parallel connections mostly adopts special traction transformer.This paper discusses the several traction transformer in the use of saving AT in the substation,is given the traction transformer impedance parameters without changing the performance requirements of the AT power supply system when save the AT transformer in the substation,and its equivalent leakage resistance calculation formula is presented.Combined with actual the AT transformer connection mode,the paper analyzes the current distribution of the AT power supply system with parallel connections when the single point of short circuit happened in the T-R and the T-F.Deriving the fault location formula of boosting currents ratio of ATs,currents ratio of up and dawn rail and currents ratio of cross line in regardless of the mutual inductance of up and down rail,transformer leakage reactance and admittance of rail to ground,and combining the research discusses the correction formula in application of boosting currents ratio of ATs.Using the algorithm of conductor merge to equivalent merge the up and down rail in the AT power supply system with parallel connections,then converted the equivalent rail to other lines by the method of asymmetrical coordinates,simplified the all parallel AT traction network as equivalent four phase model of the up and down contact lines,the up and down feeder lines,that obtained the traction network equivalent impedance 4×4 matrix.Based on the traction network equivalent model,studied the parallel AT power supply mode generalized symmetrical component model by using the method of generalized symmetry component,based on this model the formula of fault location that calculate the transformer leakage reactance was deduced.And it shows that the leakage reactance has no impact on the currents ratio of up and dawn rail and currents ratio of cross line,then gives the formula of boosting currents ratio of ATs that calculate the transformer leakage reactance,and combined with the correction formula by field application,then verified conclusion by RTDS modeling simulation.