Electricity supply：The power supply system is the energy source to secure the operation of subway, thus constituting an important part for the safe operationa of subway. Beijing subway’s power supply system consists of a 10KV power system, a 750V direct current traction power system, a 400V low-voltage power distribution system and emergency-use lighting system. The urban power grid source introduced adopts a mode of combining concentrated and diversified power supply. The power supply system, as far as its mode of composition is concerned, is highly reliable, stable and safe, which can secure the continuous power supply.  

The nominal voltage of the traction power supply system of the subway of Beijing is 750V，and the mode of contact power supply is adopted for contact network. For traction power supply system, it works with the double sources or single source, which means to supply power to one power-needing area from two neighboring power stations or from one separate transformation station.  

The setting-up of the power supply system of the subway is made through automatic remote control. The power distribution center is in charge of the centralized-controlled distribution, order-sending and management and the remote control, monitoring and supervision over all power transformation substations.