Protection of 25Kv electrified railway system

Improving a reliability of electrified railway operation system requires protection against overvoltage, particularly those of atmospheric origin. The most serious threat to the traction system is lightning when it strike the mast or conductors. to protect a system from this phenomenon, the ZnO arrester are used. In the present investigation the system under study is developed and each element is represented by a model corresponding in EMTP Program. Protective effect of the surge arrester and discharge current which passes through it is analyzed and discussed in case lightning strikes a mast. The simulation results have shown that the surge arrester reduce overvoltage in primary power transformer traction below 150KV under critical conditions.