Voltage-Sag-Profiles-Based Fault Location in High-Speed Railway Distribution System

Operation parameters of the high-speed railway distribution system can be obtained from remote terminal units installed in box-type substations. Therefore, the voltage sag profiles may be utilized for fault location. This paper proposes a novel strategy for fault location in a high-speed railway distribution system by measured voltage data of existing box-type substations. The proposed method makes use of the difference between the calculated voltage and measured voltage at the end of the lines to locate the fault. Assuming that the fault occurs at any possible box-type substations along the lines, the faulted line section is identified with the defined difference sequence, and then the exact fault location can be obtained with a searching procedure in the identified fault section. Considering the effect of equivalent capacitance, each line section is modeled with the pi model to improve accuracy of fault location. The validity of the proposed method is tested extensively in the simulation model of a real high-speed railway distribution system. The proposed method is not affected by fault type and fault resistance. Furthermore, comparing with the offline detection method of underground cables, it does not need any additional devices and will not interrupt the system operations.