高速列车“车-轨”回流耦合机制与抑制方法

The grounding system of high-speed trains consists of working grounding and protective grounding. On the one hand it is the main path of traction current and thunder-strike current, and on the other it provides common reference potential for train electrical equipment; the availability and reliability of grounding systems directly affect the safety of personnel and equipment. Different from the solid grounding, the grounding system of high-speed trains is dispersed on different train' bodies. Moreover the distribution, grounding point layout and the path of current reflux of current flow are mutually coupled while the trains are moving with high speed. When the grounding scheme does not match the path of reflux on rails, the abnormal wear of carbon brush, rail insulation burning, high surge voltage and so forth will appear, which threat the safety of train operation seriously. This project mainly researches the distribution character and propagation law of reflux on high-speed trains. The influence produced from grounding scheme, parameters, layout etc. on the train bodies' potential, train bodies' current and rail insulation burning is analyzed. The dynamic coupling model of 'catenary—train body—rail' system is built for researching the dynamic coupling mechanism between train' bodies and reflux on rails, analyzing the influence on transient potential on train' bodies from different grounding parameters and ascertaining the matching relationship between grounding reflux of train' bodies and rail reflux. Based on the consideration of the grounding reflux and transient potential of the train' bodies, the optimal matching strategy of the dynamic grounding system of high-speed trains is proposed.

高速列车接地系统分为工作接地和保护接地，一方面它是牵引电流、雷击电流等的主要回流途径，另一方面它也为车载设备提供公共参考地电位；接地系统的有效性及可靠性直接影响车载人员和设备的安全。不同于变电所的固定接地，高速列车接地系统分散在不同的车体上，而且随着列车的高速移动状态，接地回流分布与接地点布局、回流途径相互耦合。当车体接地方式与钢轨回流途径不匹配时，会出现接地碳刷异常磨损、钢轨绝缘节烧损、车体浪涌电压过高等问题，严重威胁列车的运行安全。本项目围绕高速列车接地回流的分布特性与传播规律，解析接地方式、参数、布局等对车体电位、车体电流、绝缘节击穿的影响机制，构建 “接触网—车体—钢轨”系统动态耦合模型，研究车体接地回流与钢轨回流的动态耦合机制，解析接地参数对车体瞬态电势的影响规律，探明列车接地与钢轨回流系统的参数匹配关系。综合考虑接地回流与车体瞬态电势，提出高速动车组移动接地系统的优化匹配策略。

作为高速列车能量泄放的唯一通道，高速列车在行驶过程中接地电流通过车轮与钢轨之间的滚动电接触进行传输；接地电流通过接地轮对注入钢轨，然后通过钢轨、回流线、综合地线等渠道回流至牵引变电所。高速列车接地系统分为工作接地和保护接地两种接地方式：工作接地为牵引变压器输出的牵引电流提供泄放通道；保护接地为车体电流、雷击电流等提供回流途径，另一方面它也为车载设备提供公共参考地电位；接地系统的有效性及可靠性直接影响车载人员和设备的安全。不同于电力系统中传统的固定接地方式，高速列车接地系统分散在不同的车体上，而且随着列车的高速移动状态，接地回流分布与接地点布局、回流途径相互耦合。当车体接地方式与钢轨回流途径不匹配时，会出现接地碳刷异常磨损、钢轨绝缘节烧损、车体浪涌电压过高等问题，严重威胁列车的运行安全。本项目围绕高速列车接地回流的分布特性与传播规律，解析了接地方式、参数、布局等对车体电位、车体电流、绝缘节击穿的影响机制。基于车轨的实测阻抗参数，搭建了二维的 “接触网—车体—钢轨”系统动态耦合模型，研究了列车经过吸上线过程中“车-轨”接地阻抗发生剧烈动态变化时车体接地回流与钢轨回流的动态耦合机制，分析了当升降弓及列车过分相操作车载真空断路器时车体瞬态电势的动态变化规律。解析了接地点布置、接地参数对车轨回流及车体瞬态电势的影响规律，探明列车接地与钢轨回流系统的参数匹配关系。为了提高接地回流模型的模拟精度，采集了车体与轨道横向、径向和垂向的阻抗参数，构建了三维的 “接触网—车体—钢轨”系统动态耦合模型，并探明了不同接地点布置方式对列车接地性能的影响，并通过对比得到了合理的接地点布置方式。综合考虑接地回流与车体瞬态电势两项重要性能指标，依托粒子群优化算法对列车上多点接地系统中每一个接地点的阻抗参数进行多变量优化，提出了能够同时抑制接地回流及车体过电压的高速动车组移动接地系统的多变量多目标优化匹配策略。