This standard covers the application of de surge arresters for transicnt overvoltage protection of de transit electrifcation systems. These de transit electrification systems include light rail, heavy rail, streetcar, and trolley bus systems. This standard covers the selection and application of metal-oxide varistor (MOV) gapless-surge arresters to divert surge energy away from the transit system components. It does not cover low-voltage SPDs that are required within dc traction power system equipment, such as rectifier units, vehicle propulsion systems. or other sensitive cormponents of the de transit system.
