The Lightning Impulse Characteristics Of The Grounding Of The Weak Current Equipment Along The High-Speed Railway

Since the opening of the high-speed railway, lightning affects the driving safety and the efficient operation of the high-speed railway seriously. Lightning may destroy the equipment, disrupt the transport, cause traffic accidents and casualties seriously. Grounding can provide effective channel for the lightning current, in our country we use the integrated grounding system in the building of the high-speed railway which is based on the connecting ground wire. When the high-speed railway being struck by lightning, the integrated grounding system will be with high impulse voltage and impulse current, and the grounding of the weak current equipment will appear transient overvoltage, the weak current equipment will be influenced. So it has very important significance to clear the spread of the lightning current in the lines, the ways of the lightning current entering the grounding of the weak current equipment and the current value, the influence scope of lightning on the weak current equipment, and investigate the effects of different grounding modes on the influence scope of lightning.Firstly, the article established a model of the high-speed railway roadbed section by the software CDEGS which including pillars, the suspension lines and the integrated grounding system. We got the propagation characteristic of the lightning in the high-speed railway, as well as the lightning impulse response of the model, cleared the effect of the railway structure, the location of lightning strikes, the soil parameters on the lightning impulse characteristic of the integrated grounding system, and obtained the regular pattern. Secondly, the article established a transient model of the grounding of weak current equipment which was based on the model of a railway, calculated the lightning impulse response of the grounding of weak current equipment when the pillar or the weak current equipment was stroke by lightning. The influence scope of lightning on the weak current equipment under two lightning conditions was got, the effect of soil resistivity and the grounding resistance on the impulse response and the influence scope of lightning was cleared. At last, the article established the transient models of the grounding of weak current equipment at the other two grounding modes, got the influence scope of lightning at different grounding modes, and analyzed the effect of each factor on the influence scope at different grounding modes. The final results show that, under the condition of the pillar being stroke by lightning, the influence scope of lightning is widest when we use the integrated grounding system. Under the normal condition of the weak current equipment being stroke by lightning, the influence scope of lightning is least when the grounding of weak current equipment is not connected to the connecting ground wire, the influence scope when we use the integrated grounding system is close to the scope when we use the small-scale integrated grounding system.