Fault Location Of Metro DC Traction Network

As a safe and environment-friendly city rail transportation, subway not only solves the problem of traffic congestion in large and medium-sized cities, but also brings great convenience for people to travel around the world. With the increasing demand for urban rail transit, the requirements of subway reliability and security are getting higher and higher. The safety issues of the subway traction power system, which provides traction power for urban rail vehicle, are directly related to the stable operation of the whole subway electric locomotive. Therefore, this research on fault location is based on RTDS (Real-Time Digital Simulator), according to the characteristics of subway power supply system. It is significant to realize the accurate location of fault, speed up the repair time, and improve the safety and stability of the whole system.The subway traction power supply system is analyzed in this paper thoroughly. The subway catenary system model is constructed according to the defining procedure of Cbuilder in RTDS, and DC traction transformer model has also been built with the analysis of the 24 pulse rectifier circuit and phase shift rectification mechanism. Based upon these work, the subway traction power supply system and simulation verification are accomplished.The calculation of traction network short circuit is a prerequisite for fault location. Then the characteristics of feeder currents at the outlet of the transformer substation in the near and far short-circuits are obtained respectively on the basis of the steady state calculation circuit and the differential equation.A field subway fault location algorithm by double-ended feeder current has been analyzed, and on this foundation, this paper considers voltages into the location method and presents an improved location method. Besides, in order to obtain more accurate ranging results, the principle of double-ended fault location based on the least square method and searching method are analyzed. Simulation results show that both two terminal fault location algorithms have high precision, while the latter is less affected by the parameters of the contact network. The processing of all the simulation data, which comes from Script files in RTDS, is achieved via MATLAB programming.