The Generating Mechanism and Suppression Measure of the ‘Wheel-Rail’ Rolling Arc for Electrified Trains

Abstract

As the ‘main blood vessel’ of the traction power supply system for high-speed trains, the ‘wheel-rail’ coupling grounding reflux system provides the vital channel to send traction current back to terrestrial substations; meanwhile, the rail track also plays a role in transmitting the train's occupancy signal to the control system. An insulated joint is embedded almost every 1.5–5 km along the rail track to isolate adjacent track sections for realising both transmission of traction current and separation of the track occupancy signal. When a wheel rolls across an insulated joint, the transient variation of the reflux paths with the potential difference between the two adjacent rail ends possibly triggers an arcing phenomenon around the insulated joint, which seriously threatens the operational safety of trains. In order to explore the generating mechanism of the ‘wheel-rail’ rolling arc, a dynamic current-carrying experimental platform is built to observe the evolutionary process of the ‘wheel-rail’ rolling arc, as the main influencing factors of the arc are explored. Considering the arcing criterion, different combinations of grounding resistors have been attempted, as the optimum is ultimately achieved based on the brute force method for suppressing the ‘wheel-rail’ arc effectively.