本标准涵盖了直流输电电气化系统瞬态过电压保护用直流电涌放电器的应用。这些直流交通电气化系统包括轻轨、重轨、有轨电车和无轨电车系统。本标准涵盖了金属氧化物变阻器（MOV）无间隙电涌放电器的选择和应用，以将电涌能量从运输系统部件转移出去。它不包括直流牵引电力系统设备所需的低压SPD，如整流器装置、车辆推进系统或直流传输系统的其他敏感部件。

This standard covers the application of dc surge arresters for transient overvoltage protection of dc transit electrification systems. These dc 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 components of the dc transit system.