Study On The Over-voltage Mechanism And Suppressing Method For High-Speed Train

High-speed railway, as the integration of multiple high-technology in contemporary era, has been developing at an alarming rate from all over the world for its characteristics of speediness, high efficiency and environment protection. High-speed Electric motor train unit (EMU) plays a core role in the rail transportation system which has great influence on the safety of passengers as well as the electrical equipment. It’s precisely because of the large percentage of bridges and tunnels in the railway route, complex electrical coupling among vehicles, overhead contact lines and traction substations, frequent change of electrical contact state between bow and contact line at the high-speed, harsh refraction and reflection of voltage wave caused by numerous grounding point in vehicle body, there are unprecedented challenges in the overvoltage protection of high-speed trains. Therefore, there is important academic value and project significance to study the formation mechanism, propogation and restrainned method of over-voltage from the viewpoint of vehicle-catenary-substation system combined with operating conditions of high-speed train. In this paper, a simulation model of overhead contact line of high-speed railway traction power system, viaduct electromagnetic coupling and dynamic electrical contact of the bow-net system in EMU have been established taking into consideration of the coupling of the bridges and tunnel structures, contact state of the pantograph-catenary system. The formation mechanism of overvoltage of phase separation, plus with lift bow surges and other transient overvoltage influencing factors were studied as well as its suppression strategies. Influencing factors of over-voltage’s amplitude were analyzed, suppressing strategies were proposed at last.A distributed parameter mode of high-speed vehicle body was built based on actual structural parameters. The route of transmission voltage on the vehicle body and the refraction and reflection characteristics of the voltage wave in high voltage cable between every carriage were studied. The influence of body grounding type and parameters on the contact potential and body returning was analyzed, and corresponding tests were carried out to propose a new body grounding method. The coupling method, coupling approach and propogating characteristcs were analyzed. New grounding strategies were proposed based on the above analyzing results.A comprehensive grounding system model was built based on key parameters of grounding impedance and shunt coefficient. The traction current and transient over-voltage propagation characteristics of the high-speed train in the railway rail and integrated grounding system was analyzed. The formula of comprehensive grounding impedance and the shunt coefficient were proposed. The influence on shunting current and suppressing over-voltage with the change of grounding line paramenters had been analyzed. Related experiment had been carried on SUI-YU railway.A model to analyze the high voltage equipment on the roof of high-speed train was built. The electric field near the high voltage equipment and the flow field distribution were studied. The relationship between insulator surface pressure distribution and the contamination flashover voltage was analyzed. Finally, the insulation coordination parameters of high voltage equipment on the roof of the high-speed airflow were proposed.