Study On The Influence Factors Of Lightning Strike Selectivity In High Speed Rail Traction Power System

Lightning is one of the main factors affecting safety of high-speed railway. In the paper, the main problems of lightning protection for power supply system in high-speed railway were studied. Analysis showed that because of the high proportion of viaduct, integrated ground and other features along the high-speed railway, the lightning protection for traditional railway system is inefficient. However the homologous standards in foreign developed countries such as Germany, Japan are not fit for the high-speed railway in China, due to the differences in geology, climate and power supply system structure.Based on the characteristics of high-speed railway, the overhead contact system (OCS) model on the viaduct was established in the paper. The attracted lightning width of high speed railway traction power supply system which caused by direct lightning was analyzed.By using PSCAD simulation software, the lightning withstand level of insulator when lightning strike in the catenary different locations was gotten.Combined with the lightning activity dater along the Beijing-Shanghai High-speed Railway, the influence of viaduct to the trip times caused by lightning stroke was studied. The research results show that the attracted lightning width of Beijing-Shanghai line’s OCS increased obviously with the increasing of viaduct height and lightning current. When lightning striked directly to the catenary line, the lightning current whose amplitude was greater than about3kA could cause catenary insulator flashover.When the height of viaduct is16meters, the number of lightning flashover is2times than that without viaduct.For analysising the high-speed rail’s lightning strike selectivity, the improvements formula for calculating induction overvoltage of high-speed railway catenary was given. The direct lightning and induction lightning range of traction power supply system were defined. The induced lightning drawing range in different heights of viaduct was studied. Combined with the lightning activity dater along the Beijing-Shanghai High-speed Railway, the influence of viaduct to the trip times caused by indirect lightning stroke was studied. While the shielded cable was existed and the lightning dropped in direct lightning range, the insulation flashover times caused by induced overvoltage were studied.Although the traction power supply system’s induction lightning overvoltage and lightning drawing range were increasing with the height of viaduct, but the overall times of flashover caused by induction lightning are less. The flashover times even can be ignored. When the lightning dropped in direct lightning range, the overall times of flashover caused by induction lightning overvoltage has little change. But the total times is greater than the situation that the lightning dropped in induced lightning range.Finally, this article given some recommendations for improving the high-speed railway’s lightning protection system:erect lightning conductor or uplift the PW line to protect catenary line; improve the grounding system of traction power supply system; install protection gap and surge arresters on both ends of the insulator; establish lightning monitoring system of high-speed railway.