Study on Methods to Reducing Rail Potential of High-Speed Railway

The rail potential is the voltage between running rails and earth under operating conditions when the running rails are utilized for carrying the traction return current or under fault conditions. Main characteristics of high-speed railway traction load are high-power and high operating currents. It may cause rail potential to exceed limits and endanger the safety of persons. So it is worth studying that how to keep the rail potential below a critical value under all expected conditions. The models of return circuit system of traction power supply system (TPSS) of high-speed railway are built using SimPowerSystems toolbox provided by MATLAB/SIMULINK in this paper, and the simulation results are given out. Based on compare and analysis, several factors that have obvious influence on rail potential are pointed out, such as the conductance per unit length between running rails and earth. The effects of some measures to low rail potential are also compared and a reasonable scheme is brought forward. It is illustrated that the scheme may ensure safety of persons through simulation