GB/T 999-2008

This standard specifies the rated voltage used in DC power traction systems. This standard applies to the voltage of the power supply lines of DC power traction systems under normal operating conditions. It involves the average value of DC voltage. This standard applies to the following electrified transportation: a) Electrified transportation in industrial and mining enterprises (including underground tunnel transportation); b) Urban rail transit, such as metro electric vehicles, light rail trains, trams, rapid trams, low-speed magnetic levitation trains, etc.; c) Urban trolleybuses and dual-energy trolleybuses; d) Electrified railways in suburban areas (including satellite towns) and local railways. This standard does not apply to: a) Voltage used for indicating or transmitting signals (measurement values); b) Standard voltages of components or equipment units in electrical equipment; c) Cranes, mobile platforms, and cable cars.