考虑电动斥力的真空断路器刚柔耦合系统机械特性研究

Research on structural characteristics of rigid-flexible coupling system of VCB considering electro-dynamic repulsion force

针对真空断路器分闸过程涉及到的灭弧室侧电磁力与操动机构侧机械运动的耦合计算问题,结合Mayr-Cassie混合式电弧模型、灭弧室电磁场模型以及操动机构刚柔耦合动力学模型提出一种断路器分断过程电-磁-机械动态特性耦合计算方法。基于真空断路器分断过程动态特性计算结果,通过显式动力学方法对分闸过程中触头弹簧系统的冲击碰撞现象进行模拟计算,并结合应变寿命理论及Miner累计损伤理论计算触头弹簧结构的工作寿命,在此基础上对触头弹簧结构进行优化改进工作。研究结果表明:在断路器分闸过程中电动力方向并不总是为触头斥开方向,在超程阶段结束之前动触头承受的电动力为斥开方向,在超程结束后动触头承受电动力为闭合方向;在承受分闸冲击时,优化前的触头弹簧结构应力危险范围在弹簧销与导向套的接触界面处,应力数值为273.28 MPa,其疲劳寿命为2027次,优化后的触头弹簧结构疲劳寿命为12030次,满足断路器产品额定机械寿命的要求。

Aiming at the coupling problem of electromagnetic force on vacuum interrupter and mechanical motion on operating mechanism,a coupling calculation method of electro-magnetic-mechanical dynamic characteristics of circuit breaker was proposed based on Mayr-Cassie arc model,electromagnetic model of interrupter and dynamic model of operating mechanism.The collision phenomenon of contact spring during opening process was calculated by explicit dynamic method.The fatigue life of contact spring was calculated,and the structure of contact spring was optimized.From the result we can see:the electrodynamic force of the moving contact is in the repulsion direction in the over-range stage,and the electrodynamic force of the moving contact is in the closed direction after the over-range stage.The high stress of the contact spring is at the contact interface between the spring pin and the guide sleeve,where the stress is 273.28 MPa,the fatigue life is 2027 times before optimization.The fatigue life of the contact spring structure is 12030 times after optimization,which meets the requirement of mechanical life.