动车组过吸上线时保护接地电流分布特性

Distribution Characteristics of Protective Earthing Current When High-speed EMU Passes Through Boosting Cable

动车组经过吸上线时,电流在与吸上线、钢轨联接点接触的保护接地的轮对上发生局部集中,容易引起碳刷异常磨耗,接地回流不均,对动车组的安全运行构成了一定的威胁。本文利用PSPICE软件建立动车组过吸上线过程的仿真分析模型,分析过吸上线时各保护接地电流的变化与相位变化规律,并与实测数据对比验证,在此基础上,提出了有效抑制措施。仿真和试验结果表明:动车组过吸上线时,其保护接地电流依次增大到最大值,且两头车保护接地电流最大,达到170A;在同一车体上,离工作接地较近的接地点过吸上线时,该车体的两个接地回流相位相同,而较远的接地点过吸上线时,相位相差180°左右;将各车体的两个接地点均设置在离工作接地较远的位置,且在头车上加设电阻器能有效抑制各车体过吸上线时的电流。

When the EMU passes the boosting cable, the local concentration of current occurs at the wheel set of protective earthing that is in contact with the contact point of the boosting cable and rail, which may lead to ab normal wear of the carbon brush and uneven ground return, which poses a potential threat to the safe operation of the EMU. In this paper, the PSPICE software was used to establish the simulation analysis model to simu late the process of EMU passing through a boosting cable and to analyze the changes of the protection earthing current, and the change law of the phase. By comparing with testing data, effective control measures were put forward. The simulation and experimental results show that when the EMU passes through the boosting cable, its protective grounding current in turn increases to the maximum value, with the protective earthing current of the lead cars being the largest, reaching 170 A. For the protective grounding points under the same carriage, when the protective grounding point closer to the working grounding passes the boosting cable, the two protec rive grounding return phases of the carriage are the same, while the phase difference is about 180 degrees when the protective grounding point farther passes the boosting cable. Placing the two grounding points of each car at a position far from the working grounding, and the addition of a resistor on the head car can effectively suppress the current of each car when passing the boosting cable.