Evaluation and Analysis Model of Stray Current in the Metro Depot

With the rapid development of the dc metro system, the hazard of stray current is increasingly serious. Due to the direct grounding of the track and the lack of a stray current collector system (SCCS), the metro depot has become a weak link in the protection against the stray current. In order to evaluate and analyze the stray current distribution of the metro depot, the evaluation model of stray current in the metro depot is proposed in this article. Based on the piecewise-linearized volt-ampere characteristic, the one-way conduction device (OWCD) of the depot is modeled by a current source paralleled with a resistor. The distribution of stray current in the depot is calculated based on the nodal analysis method. The validity of the proposed evaluation model is verified by comparing the calculation results with the field data. Moreover, based on the proposed evaluation model, the distribution of stray current in the depot when the train operates at different positions is analyzed. The results show that the train in traction operation on the mainline far away from the depot is more likely to aggravate the stray current in the depot than when it is close to the depot.