Study On Protective Schemes Of Bilateral Traction Power Supply Systems For High Speed Railways

Since 1961, the first single-phase power frequency AC electrified railway lines completed, the traction power supply systems is using the unilateral power supply in practical engineering applications. In recent years, with the gradually expanding of the scale of construction and operation and the increasing operating speeds of high speed railway, the power quality and reliability of traction power supply system have be put forward higher requirements.The combination between bilateral power supply technology and AT traction power supply technology can better improve the quality of power supply, improve the supply capacity, balance the traction load better and reduce the interference on the communication effectively. Compare with the unilateral power supply system, the bilateral power supply system can reduce the number of electrical sectioning device. It can better adapt the requirements of traction power supply system. However, bilateral power supply system put forward new demands for relay protection. The through current brings difficulties for relay protection configuration and setting. Thus, the solution of protection program for bilateral AT traction power supply system, which brings practical technical and economic significance for the application and promotion of the bilateral power supply technology.In this paper, based on the AT traction power supply system of high-speed railway, transformed the connection style of traction substations and section post, established the bilateral AT traction power supply system. Based on the system, analyzed and calculated the traction across current, analyzed the T-R, T-F, and F-R short-circuit parameters of traction power supply system. Meanwhile, in this paper, the MATLAB/SIMULINK model of bilateral AT traction power supply system was established. The simulation results show the correctness of circuit analysis and calculation and provide a good basis for the relay configuration analysis.With the simulation Conclusions, analyzed the new features of traction transformer protection and feeder protection of bilateral AT traction power supply system, proposed the protection program, the traction protection process, fault isolation mode, power supply recovery programs and protection setting calculation. The simulation results verified the reliability of distance protection. With the model, analyzed and discussed the influence of transition resistance on the traction feeder distance protection, and proposed measures for improvement at the last.