交流供电制式下矿山法地铁隧道的牵引回流分布特征分析

Distribution Characteristics of Traction Backflow under AC Power Supply System in Mined Metro Tunnel

为了提高城市轨道交通的线路运输能力和列车运行速度,我国几个主要城市新规划了25 kV交流供电制式的城市轨道交通线路。交流供电制式下牵引回流系统的泄漏电流侵入周边管线设备后,将威胁到人员与设备的安全。建立矿山法地铁隧道模型,对比研究了交流、直流2种供电制式下泄漏电流的大小及分布特征。研究发现:交流供电制式下的泄漏电流远大于直流供电制式下的泄漏电流,其泄漏电流大小随牵引供电区间长度的增加而快速增大;钢轨对地泄漏电阻和土壤电阻率均不是泄漏电流的主要影响因素;交流供电制式下的泄漏电流主要通过空间电磁耦合产生,减少电磁耦合强度才是降低泄漏电流的主要途径。

In order to improve the line transport capacity and vehicle running speed of urban rail transit,new urban rail transit lines with 25 kV AC power supply system have been planned in several major cities in China.The safety of personnel and equipment will be endangered by the leakage current of traction backflow system when it invades into the pipeline equipment surrounding these urban rail transit lines.The model of metro tunnel built by mining method is established,and the magnitude and distribution characteristics of leakage current under AC and DC power supply systems are compared.It is found that the leakage current of AC power supply system is much larger than that of DC power supply system,and its leakage current increases rapidly with the increase of traction power supply interval length.Rail-ground leakage resistance and soil resistivity are not the main factors affecting the leakage current.The leakage current of AC power supply system is mainly generated through space electromagnetic coupling,and reducing the intensity of electromagnetic coupling is the main way to reduce the leakage current.