The Effect of Railway Environment on the Insulation Performance of Catenary Insulators

The form of the railway track includes open route, bridge, tunnel, and even tracks close to the coast. Therefore, insulators for catenary are exposed to more dust, salt, and moisture than general electrical equipment installed on roads. Considering this environment, insulators for AC 25kV catenary lines are designed and applied with an insulation class of 46kV and an specifie creepage distance(SCD) of Very Heavy pollution level exceeding 25mm/kV. However, there have been 185 cases of catenary insulator flashover in the past 13 years. In this paper, we analyzed cases of flashover caused by dust and moisture in tunnels, flashover caused by salt damage, and flashover of polymer insulators in high-speed railway open route, and examined the effect of railway environment on the insulation performance of catenary insulators.