Analytical Study on Improvement of Traction Substation’s Grounding System for lightning overvoltage reduction

We investigated the improvement measures of the grounding system for reduction of the lightning overvoltage at the rectifier related equipment of the railway substation. At railway substations, it is difficult to achieve completely equipotential of all equipment including rails. As an example of an old substation required improving the grounding system, we examined a simple improvement method to reduce the lightning overvoltage generated in the rectifier related equipment, which is relatively weak dielectric strength. By cutting off the overhead grounding wire connected to the grounding mesh at the rectifier related equipment side, the overvoltage occurred in the rectifier equipment can be reduced.