Study On Rail Potential Mechanism And Suppressing Method For High-Speed And Heavy-Load Railways

With the development of the national economy, freightage and passenger traffic increase rapidly. High-speed and heavy-load become the developing direction of electrified railway in our country. Since the traction power is large, traction load is heavy and traction current is large in electrified railway high-speed sections, the rail voltage is easy to become overtop, leading to the abnormal of signal equipments, which directly threatening the safety of communication equipments and people. So in this paper the generating mechanism of rail voltage was analyzed based on the survey of traction power supply system of high-speed and heavy-load railway. Then the characteristics of traction power current and its change law were explored. And an effective suppression method was proposed for that. This is of great significance to improve the operation reliability and safety of the railway electrification equipments.A rail voltage analysis model that suitable to a variety of power supply modes was proposed. The data that calculated by the model is similar to that measured from the heavy-road line between Datong to Qinhuangdao.According to the traction power supply system’s structure and the basic principle of grounding, based on the analysis of the distribution parameters of rail’s circuit, model of rail potential and current distribution was established, revealing the attenuation law of rail potential and flow of the rail current law; which illustrate the mechanism of attenuation coefficient, power supply mode and comprehensive grounding line on rail potential. According to the multimode coexistence, the power supply mode of traction power supply systems, model of traction power supply system under different power supply mode and the mode of rail with grounding line were set up. The potential distribution characteristics of rail, protection line under traction power supply system’s normal running and short circuit fault running were analyzed, making out the effect rule of comprehensive grounding system on traction power supply’s safety operation under different power supply modes.Through the researches, such as the attenuation coefficient, the rail potential, electric current, the rail lateral, longitudinal voltage measurement methods, the rail potential monitoring system was established. For the phenomenon of high-potential of high-speed and heavy-load electrified railway, overloading on the high-speed lines between Datong to Qin huangdao, Beijing to Tianjin, Suining-Chongqing, etc, the measurement and analysis were done, such as the rail potential, the rail current, the shunt coefficient. According to the mechanism of rail potential and its influencing factors, the effect that the comprehensive ground reducing rail potential, grounding potential and flowing lines was explained. Respectively from the rail laying way, traction network structure, catenary pillar structure and comprehensive laid ground wire, etc, the relevant measures of the inhibition of rail potential were put forward.