城轨直流牵引供电系统回流安全问题逐渐成为目前研究的重点之一,然而与走行轨等电位连接的屏蔽门往往因绝缘不理想而对线路回流安全参数的分布造成影响。本文针对屏蔽门绝缘状态对城轨回流安全参数的影响,建立了多列车动态潮流仿真模型,并基于无锡地铁2号线的数据进行了仿真分析。结果表明,屏蔽门绝缘状态薄弱将导致线路回流安全参数明显增加,威胁周边设备及人员安全。当两处屏蔽门绝缘薄弱时,将形成杂散电流的泄漏回路,加剧回流安全参数的异常升高,且屏蔽门绝缘阻值越低,线路钢轨电位幅值越低,但杂散电流水平越高。此外,多个屏蔽门绝缘薄弱时,线路回流安全参数将急剧增加,对周边设备以及乘客、工作人员的安全造成严重的威胁。

The reflux safety of DC traction power supply system in urban rail transit has gradually become one of the current research focuses. The shield doors that are equipotential with the running rails will affect the distribution of reflux safety parameters due to the unsatisfactory insulation. Aiming at the influence of the insulation status of the shield doors on the reflux safety parameters, a simulation model of multi-train dynamic power flow is established, and simulations are carried out based on the data of Wuxi Metro Line 2. The results show that the weak insulation status of the shield doors will result in a significant increase in the reflux safety parameters, threatening the safety of equipment and personnel. When the insulation of the two shield doors is weak, a leakage loop of stray current will be formed, which will aggravate the abnormal increase of the reflux safety parameters. The lower the insulation resistance of the shield doors, the lower the amplitude of the rail potential, but the higher the stray current. In addition, when the insulation of multiple shield doors is weak, the reflux safety parameters will increase sharply, posing a serious threat to the safety of equipment, passengers and staff.