Research On Lightning Protection Of High-speed Railway Traction Network

With the rapid development of high-speed railway, the security issues of the tractionpower supply systems are also taken more and more seriously. But the accident that thetraction power supply system of high-speed railway was struck by lightning often happened inrecent years. As far as possible, to avoid the bad influences which lightning strike brings toour travel, the protection against lightning off traction power supply system of high-speedrailway should be got more attention.Firstly, the dissertation expounds the basic theoretical knowledge of lightningmechanism and lightning parameters in detail. At the same time, introduces the methodswhich are used to calculate shielding failure flashover rate (SFFOR), also the applicationsituation, the advantages and disadvantages of each method.Secondly, in lightning protection calculation in engineering, there are mainly twomethods based on electro-geometric model (EGM) to calculate SFFOR, which are “theexposure distance” and “the exposure arc”. But the first method does not take lightning strikeangle into account, which leads to the calculation results don’t match the actual situation; andbecause the second method takes arc as straight line to calculate, makes the calculation resultsare bigger. Aiming at these deficiencies, the high-speed railway’s EGM is set up, consideringthe strike angle and the viaduct sections, extend the concept of exposure distance to the EGMwith any angle, thereby the shielding failure area of high speed railway is get. And a formulathat high speed railway is struck by lightning with a certain angle is deduced. By calculating,it is concluded that incident angle affect the lightning flashover rates of high speed railway.Meanwhile, according to the scope of the lightning strike-angle of shielding failure andthe SFFOR of a certain strike-angle which are deduced before, the calculation formula ofhigh-speed railway lightning shielding failure flashover rate is get, by accumulating the singlestrike angle date of SFFOR, which take into account the change of lightning strike angle inthe plane space. Calculating and analyzing, the improved model to calculate not onlyovercome the weakness of the method applied exposure arc whose results are bigger, but alsois closer to simulate practical situations, so as to provide reference for the high speed railwaylightning protection.Finally, by using of PSCAD software, the simulation models are set up, the lightningresisting level of the catenaries are recorded and simulated, which shows how these factorssuch as the grounding resistance of pillar, the height of viaduct, with or without surge arresterinfluence the lightning resisting level of the catenaries. After that, basing on the theory ofEGM, a right height formula of the installation of ground wire is put forward, considering theviaduct situation. According to the results of the calculation and simulation for high speed railway, lightning protection advice are proposed.