Study On Rail Potential And Reducing Measures Of AT-Fed Traction Power System

As the load of high-speed railway increasing, short circuit of traction power supply system and lighting stroke faults, that will generate higherrail potential, cause damage toequipmentalong the railway and even lead to driving accidents and casualties. The high-speed railway consists of subgrade, viaduct and tunnel section, the traction network mathematical models and the calculation of electrical parameter of these three sections are different. So it makes a significance to study the rail potential distribution of different sections and the measurements to reduce that in different condition.The AT traction network studied in this paper conbinedwith multi-conductor transmission line is built in this dissertation. Basing on Carson theory and mirror image method,the dissertation calculates the electrical parameter of subgrade and viaduct. The electrical parameters of tunnel wires are calculated byall around infinite tunnel model.The AT power supply modesstudied in thisdissertation are built in the Matlab/Simulnk simulationplatform. The simulation results show that the rail potential in viaduct is the highest, the rail in tunnel is slightly lower than that in subgradein normal conditions; When T-R short fault occurs, the highest rail potential section is viaduct, followed by tunnel, subgrade. Setting grounding line.etc can effectively reduce normal rail potential, and limit it to normallevelspecified in the IEC62128-1 standard. The models of integrated grounding systems in thisdissertation have been established in CDEGS in order to get shock response property. The simulation results indicate that the highest potential in rail and grounding line of viaduct is the highest, the highest potential in rail and grounding line of tunnel is slowly higher than that in subgrade, When the distance between lightning strikes pillar and the right side of transformers is 250m, or the position oflightning is the pillar of transverse cable. Focusing on the problem of a sharp rise in potential of rail and grounding line caused by lighting stroke faults, the dissertation givesprotection suggestion.