The two wires on the high-speed rail track are transmission lines that are erected along the railway line to supply power to electric locomotives. The current that the high-speed rail trains rely on is transmitted through the catenary at the upper end of the locomotive. The traction substation provides electrical energy to the overhead contact line, and the high-speed train transports the electrical energy of the overhead contact line back into the train, and drives the variable frequency motor to drive the train. Once the catenary is out of power, the train's pantograph and catenary are in poor contact, which will affect the train's power supply.
From the point of circuit, high-speed rail adopts AT (autotransformer) power supply mode. The operation of high-speed rail relies on the traction power supply system to provide power to high-speed trains, and traction power supply is the primary load of the power system.