动车组运行接地回流特性分析及优化

动车组运行工况复杂且车体结构具有差异性,车下各轴端接地电流分配不均,给接地碳刷维护带来不便。为探究动车组接地回流的基本分布规律,找出改善接地回流的方法,基于PSCAD仿真软件建立动车组在高速铁路上过吸上线动态仿真模型,并结合现场实测数据验证仿真模型的可靠性,探明动车组与吸上线的相对位置移动时动车组接地回流变化规律。通过分析动车组运行过程中不同车体的各个轴端接地装置处工作接地和保护接地接地电流大小变化趋势,提出对动车组头尾车保护接地加装接地电阻器以及在部分保护接地回路串接阻值不同的接地电阻器两种接地方式优化方案。仿真结果表明:优化方式一保护接地电流较大的1车接地电流整体降低了50%;优化方式二使各车保护接地电流大小限制在72 A以内。优化后的接地方式抑制了保护接地电流大小并使各轴端接地电流分布均匀,以上结论为设计更优良的接地方案提供了理论基础。

Analysis and Optimization of Over Grounding Backflow Characteristics of EMU

The operating conditions of the EMU are complex and the structure of the car body is different.The grounding current distribution at each shaft end of the EMU is uneven,which brings inconvenience to the maintenance of the grounding carbon brush.In order to study the basic distribution law of earthing backflow of the EMU and find a way to improve earthing backflow,this paper establishes the dynamic simulation model of the EMU passing the suction line of high-speed railway based on the PSCAD simulation software,,and verifies the reliability of the simulation model with field measured data.It also proves the variation law of the grounding return of the EMU when the relative position of the EMU to the suction line moves.By analyzing the changing trend of working grounding and protective grounding current at each shaft end grounding device of different car body in the running process of the EMU,the optimization scheme of installing grounding resistors at the head and tail of the EMU and connecting in series grounding resistors of different values to partial protective grounding circuits is put forward.The simulation results show that the optimization method 1 reduces the grounding current of NO.1 car of large protection ground current by 50%;the optimization method 2 limits the protection ground current of each car to 72 A.The optimized grounding method suppresses the magnitude of the protective grounding current and makes uniform the grounding current distribution of each shaft end.The above conclusions provide a theoretical basis for designing better grounding schemes.