Study Of Fault Location Method For Metro Traction Power Supply System

The subway has been one of the main traffic tools for citizens because of the traits of rational utilization of underground space,beautifying the city and the comfort and convenience. With the establishment of the subway in big cities around China, it is critical to guarantee the operation safety of the metro.The fault of metro mostly happens on Catenary.To ensure the safety and the stabilization of the metro traction power supply system,when the fault happens,the fault location can be detected in the shortest time.And then clearing the fault and completing the power restoration.lt has important practical significance for the normal operation of metro to reduce the loss caused by the fault as much as possible.This paper analyzes the the subway traction power supply system thoroughly and use PSCAD/EMTDC to establish the model of12pulse rectifier unit,24pulse rectifier unit, catenary and the rail. With the simulation process and the analysis of the comparison,the characteristic of feeder current and voltage in transition resistance and inductance in short circuit state has been obtained.Analyzes the existing ranging method and choose the more adaptive method based on the differential equation to research.The theory based on the differential equation is used to analyzes the Electric relationship of the short circuit fault of the positive pole and the negative pole between the two adjacent traction substation.And the least square method is used for solving the problem.under the condition of using uniform traction network parameters,the method based on differential equation has certain accuracy on measuring the distance.the ranging error is mainly caused by the inaccurate parameters of traction network. In order to reduce or even avoid the effects caused by the uncertainty parameters of traction network to the measuring results, a new adjusted double-end domain algorithm based on catenary parameters has been studied.This method is more accurate than the existing method based on differential equation and the measuring results are not affected by fault location, fault resistance and the influence of circuit parameters.