There is a speed called China Speed, and there is a pride called China High Speed Rail. With the rapid development of China's electrified railways, high-speed railway electrical and electronic equipment is gradually developing towards systematization and integration, and the equipment is resistant to overcurrent. The level is getting lower and lower, which leads to the increasingly serious damage to railway system equipment caused by the intrusion of strong electricity such as lightning and induced overvoltage, which not only causes a large number of primary equipment to burn down, but also causes many secondary equipment damage. Accidents such as the exit of the integrated automation system and the tripping of the network switch have seriously affected the safe and reliable operation of the railway system.

In order to solve the problem of strong electricity (including lightning overvoltage and power frequency overvoltage) to the secondary system of railway traction substation Harm, China Railway Corporation issued "Transportation and Supply Equipment Letter [2016] No. 325 "Guiding Opinions on Optimizing Technical Schemes for Preventing Intrusion of Strong Electricity in Secondary Systems of Traction Substations" on September 1, 2016, and in 2017 July 12th Document [2017] No. 240 "Implementation Plan for Optimal Setting of Surge Protectors in Traction Substations".