直供方式接触网避雷线安装方式与防雷效果分析

雷击将造成电气化铁路接触网绝缘子闪络,影响供电的可靠性。现有的研究表明,在直供方式中,接触网的绕击耐雷水平远低于其反击耐雷水平,因此架设避雷线有利于提高接触网的整体耐雷水平,减少雷击跳闸率。研究回流线升高兼做避雷线(方案1)与单独架设避雷线(方案2)对接触网防雷效果的影响。研究结果表明,当避雷线位置合适时,两种方案均能对承力索的绕击起到很好的保护作用。单独架设避雷线时,回流线与避雷线共同作用,增大与承力索的耦合系数,并对雷电流起到分流作用,从而提高接触网的感应耐雷水平与反击耐雷水平。因此方案2的感应雷耐受水平与反击雷耐受水平均略高于方案1,但总体投资要大于方案2,现场应根据雷害的严重程度及投资比较,选取合适的方案。

Analysis of Installation and Effect of Lighting Conductor of Direct Supply Catenary

Lightning often causes flashover of insulator of electrified railway and impacts the power supply reliability. The existing researches show that,in the direct supply,the lightning-proof when lightning strikes the contact line is far below than that when it strikes the grounding line. So the lightning conductor is beneficial to improving the overall lightning-proof level of the contact system and reducing tripping rate. In this paper,the effects of the two lightning conductor modes have been researched. One is to raise the reflux wire to serve as the lightning conductor and the other is to set up a new lightning protection line. The research results show that,if the position of the lightning conductor is suitable,the two modes can all provide good protection for the catenary. But in the second mode,reflux wire and the lighting conductor act simultaneously to increase the coupling coefficient of the catenary and take part in current diverging. Therefore,the lightning-proof level of the second mode is higher than that of the first mode and its overall investment is higher than the first one. So,the selection of the appropriate mode should be based on a comparison of investment and the severity of lightning.