一种具有横纵磁场的新型真空灭弧室触头三维磁场仿真

3-D Magnetic Field Simulation of a New-type Contact with TMF-AMF for Vacuum Interrupters

对一种由螺旋槽横磁触头和杯状纵磁触头并联组成的新型真空灭弧室触头结构进行了磁场仿真,该触头内部的横磁触头和环形触头片材料为CuCr50,外部的纵磁触头的杯座材料为不锈钢。建立了三维触头结构模型,采用有限元分析方法对电流处于峰值时和电流过零时动、静触头表面和触头间隙中心处的静态磁场和瞬态磁场进行仿真,瞬态磁场计算过程中考虑到了涡流的影响。结果表明,该结构触头产生的纵向磁场在动、静触头表面及触头间隙中心处分布较均匀且磁通密度满足要求,有效磁通密度区域占触头表面积较大,电流过零后剩余磁场少,磁场滞后时间小,且导体电阻小。

In this paper,a new-type contact for vacuum interrupters is adopted for simulation,which consists of two coaxially arranged contacts,i.e.a screw-slotted transverse magnetic field(TMF) contact and a cup-shaped coil axial magnetic field(AMF) contact.The contact parts interacting with the arc for both TMF and AMF are made of CuCr50,and the stainless-steel cup used for the AMF contact can enhance the mechanical strength.A relevant 3-D contact model was built up.And the static field and the transient magnetic field concerning the eddy current effect were simulated by the 3-D finite element method(FEM).With the current at peak value and zero,the AMF distributions on the stationary and moving contact surfaces and on the mid-gap plane between the two surfaces as well as the lag time of AMF are all calculated.The simulation results show that the magnetic distribution is rather uniform on the contact surface,the mid-gap plane is with enough AMF strength,the effective AMF area is larger than that of the conventional AMF contacts,the AMF lag time is short,and the residual field and the resistance after current zero-crossing are small.