In some large station yards ,return current problems exist ,such as obstructed traction return current and high rail potential .This is particularly the case when the overhead contact system is short circuited to OCS pole .In order to study the return current characteristics of the traction return current system in large station yards ,the grounding analysis software CDEGS was used to build the corresponding simulation models address-ing two scenarios involving the normal operation of the train and short circuit of the OCS to OCS pole .A simu-lation analysis was carried out according to the established model .Based on the simulation results ,under either scenario of the normal operation of the train or the short circuit of the OCS to OCS pole ,only a small number of boosting cables work ,while other boosting cables hardly work ,thus leading to high traction current on the rail .In the case of short circuit fault of the OCS to the sole OCS pole ,the safety problem of excessive ground potential around the pole exists .In response to the above problems ,the following measures are proposed ,in-cluding erection of two more boosting cables in the vicinity of the traction substation ,connection of the ground-ing wire at both ends of the station yard with the return line ,and connection of the bottom of the sole OCS pole with the neutral point of choke transformer of bothrails .Through the simulation analysis ,the measures can im-prove the problems of traction return current and the safety problem of short circuit ,and can be widely used in railway station yard .%在一些大型站场中,存在回流不畅、钢轨电位过高等回流问题,当发生接触网对支柱短路时,上述问题更加严峻.为了研究大型站场中牵引回流系统的回流特性,需要针对列车正常运行和接触网对支柱短路两种状态进行研究,运用接地分析软件CDEGS搭建相应的仿真模型,并根据所建模型进行仿真分析.由仿真结果可知:无论列车正常运行还是发生接触网短路故障,站场中只有小部分吸上线工作,因此导致钢轨上有较高的牵引电流;在发生接触网对单独接地支柱短路故障时,支柱周围存在地电位过高等安全问题.针对以上问题,提出在牵引变电站附近多架设两条吸上线、将站场两端的贯通地线与回流线相连和将单独接地支柱底端与两侧钢轨的扼流变中性点相连的措施.通过仿真分析,提出的措施方案能够较好地改善站场中存在的回流问题并解决短路故障带来的安全问题.
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