Proposal of lightning risk assessment method based on the lightning current probability function for railway power supply system

A novel assessment method of breakdown probability at suspension insulators supposing the railway DC power supply system are proposed in this paper. This method is based on the well known lightning current probability function and comparison of lightning endurance of traction wire system between conventional DC railway and Shinkansen is performed. It proves that the introduction of grounding wire in DC railway power system is able to avoid only 36% of flashover at supporting point. The experimental data to confirm the influence of long tail lightning current on tensioned wire and insulators are also shown.