Light rail transit DC traction power system surge overvoltage protection

At present there is no industry standard or recommended guidelines for the application of DC surge arresters. It appears that such devices are applied based upon the rule of thumb without the benefit of analyzing characteristics, wave shape, and energy content of the expected overvoltage surges against the capabilities of the surge arrester. AC surge arresters are re-rated for de application. A difficulty arises due to lack of clear published application literature on the DC surge arresters, as well as lack of measured data on the DC power system transient surges. This leads to the application of surge protective devices, which may be inappropriate. This paper describes the application of DC surge arresters to a typical light rail transit (LRT) traction power system, and makes a recommendation of a need of a standard on DC surge arresters test requirements and application guidelines.