地磁暴干扰轨道电路工作的仿真计算研究

Simulation Calculation about Interference of Geomagnetic Storms on Track Circuit Equipment

在世界范围内曾多次发生过强磁暴导致铁路轨道电路失灵的事件,而磁暴影响轨道电路工作的机理缺乏系统性的研究。根据铁路系统接地线结构,分析地磁暴侵害轨道电路的物理过程和流过接收端扼流变压器的不平衡地磁感应电流;以2004年11月9日兰州地磁台监测数据和大地电导率数据为基础,运用平面波理论,计算兰州某两个牵引变电所之间铁路的感应地电场;根据铁路信号系统的接地情况和电气结构,估算轨道电路中的GIC水平;利用Matlab/Simulink软件对97型25Hz相敏轨道电路中信号继电器的轨道线圈侧电压进行计算仿真,研究轨道电路误动的可能性。结果表明:磁暴发生时信号继电器的二元二位继电器轨道线圈电压降低、电流相位偏离理想工作值,严重时可能导致继电器误动,造成铁路信号灯闪红,解释了高纬度国家磁暴导致的轨道信号灯闪红现象。

Strong geomagnetic storms have caused malfunctions of track circuits in railway systems worldwide. The mechanism that geomagnetic storms affect track circuits is unknown due to lack of systematic research. Based on ground connection structure of railway systems, this paper analyzed the physical process of geomag- netic storm disturbing track circuit and unbalanced GIC that flowed through the receiving-end impedance transformer. Based on ground conductivity data and geomagnetic monitoring data on November 9, 2004 by Lanzhou Geomagnetic Station, the earth surface potential of certain railway between two traction substations was calculated under plane wave method. Depending on the grounding and electrical structure of railway signal system, the GIC level in the track circuit was estimated. Computational simulation was conducted on the voltage on signal relay of 97 type 25Hz phase detecting track circuit by applying Matlab/Simulink software to research the possibility of malfunction of 25Hz track circuit. The results showed that the voltage on the track relay coil of the two-element two-position relay of the signal relay was reduced, and current phase deviated from ideal working value when magnetic storm happened, which may cause malfunction of the relay and railway signal lights to flash red light. This explained the nature of these faults with railway signal systems caused by magnetic storms in high latitude countries.