关键词: 市域铁路, 接地方案, 信号电缆, 单端接地, 双端接地

Abstract: Due to the high speed of a train, AC27.5 kV power supply scheme is often used in suburban railways. In the shield area, signaling cables, overhead contact lines and other strong electric cables are relatively close due to the limited laying space. Dangerous influence on signaling cables and their protective measures must be considered in the project implementation stage. Strong and weak grounding round steel or flat steel is considered to be installed on the cable supports on both sides of the tunnel wall respectively, which is equivalent to the combined through grounding cable in national railway. Based on the cable layout of overhead contact line and signaling cable in the shield area, this paper introduces preliminary calculation of the magnitude of the magnetic induction electromotive force generated by the signaling cable of electro-magnetic induction of overhead contact line when the train is operating at the highest density on basis of the design of power supply system, and gives quantitative analysis of the maximum allowable cable length considering the magnetic induction electromotive force of not more than 60 V on the signaling cable in the electromagnetic environment.Combined with the current various technical conditions and relevant test data analysis results, a protection measure and scheme for the use of double-ended or multi-point grounding for signaling cables in the AC power traction of suburban railways are proposed.

Key words: suburban railways, grounding scheme, signal cable, single-ended ground, double-ended ground