弓网电接触系统服役性能的纵向磁场优化

Axial Magnetic Field Optimization Method for Service Performance in Electric Contact System Between Pantograph and Catenary

弓网接触副是高速列车获取能量的唯一路径,决定了列车能量传递的安全与稳定。弓网运行条件苛刻,需同时面对全天候复杂环境、高速滑动振动、大容量电能传输等挑战,接触副出现过度磨耗与异常磨损。现有的弓网磨耗调控措施往往仅提升机械电气某单一方面性能,而综合性能难以同时满足大容量和长时服役需求。考虑到磁场在调控接触界面氧化与磨粒分布等方面的效应,提出引入纵向磁场的弓网磨耗主动调控思路。该文通过改变磁场参数,研究了磁场强度与极性对弓网接触副载流摩擦磨损性能的影响。结果表明:纵向磁场可有效降低摩擦系数的数值及波动性,且在载流工况下效果更显著;随着磁感应强度的增加,摩擦系数先降低后上升,磨损量则持续降低;不同极性磁场均有减缓摩擦磨损的作用。研究结果对需调版解决弓网异常磨耗问题的主动调控方法,以及提升弓网运行的稳定性具有指导意义。

The C-Cu contacts in the pantograph-contact line systems are the only way for the train to obtain energy,which determines the safety and stability of energy transfer.The operating conditions of the pantograph and catenary are harsh,because they are necessary to face the challenges of all-weather complicated environment,high-speed sliding vibration,and large-capacity power transmission.This leads to excessive and abnormal wear.The existing wear control measures of the C-Cu contacts only improve a single aspect of mechanical or electrical performance.However,the comprehensive performance is difficult to meet the requirements of large capacity and long-term service simultaneously.Considering the effects of the magnetic field in regulating the oxidation of the contact interface and the abrasive particle distribution,a new idea of active control of the wear loss between the C-Cu contact interface with the axial magnetic field was proposed.A linear reciprocating current-carrying friction test bench is built to simulate the operation mode of the highspeed railway pantograph-contact line system.The influence of magnetic field intensity and polarity on the currentcarrying friction and wear performance of the C-Cu contacts is studied by changing the magnetic field parameters.The results show:(1)When the strength of the magnetic fields changes in the range of 0~0.15 T,the wear amount of the carbon strip decreases continuously,and the antiwear effect can reach 78.9%at 0.15 T.The friction coefficient decreases and then increases,reaching the minimum value of 0.1361 at 0.1 T.The changing trend of wear amount can be explained by the influence of the magnetic field on interface oxidation,wear particle distribution,and dislocation movement.The effect of magnetic field on friction has two sides.Under certain conditions,it can slow down friction,while under other conditions,it can promote friction.The mutual competition between them forms the turning phenomenon of friction coefficient.(2)The antifriction effect of magnetic field is more significant under current-carrying conditions.This is mainly because the low-temperature environment without current inhibits the oxidation of the metal-copper interface.(3)Different magnetic field polarities all have the effect of reducing friction and wear.And there is no significant difference between the two polarities.(4)The microscopic analysis of the contact surface shows that the proportion of oxidation wear increases after applying the axial magnetic field under current-carrying conditions,which promotes the transition from severe wear to slight wear.(5)Introducing the axial magnetic field into the C-Cu sliding electric contact system can effectively reduce the friction coefficient and wear amount.Although the overall temperature rise and contact resistance of the carbon strip are slightly increased,the current-carrying friction and wear state is significantly improved.Therefore,the magnetic field can be used as an active control method to prolong the service life of the carbon strip.The research results have a guiding significance for developing new active control methods of abnormal wear and improving the stability of the pantograph-contact line systems.