中频真空开关纵向磁场特性分析：实验仿真平台设计

Characteristics of Axial Magnetic Field in Intermediate Frequency Vacuum Interrupters:Experimental Simulation Platform Design

本文研究了400~800Hz条件下纵磁真空灭弧室内的磁场特性。首先根据麦克斯韦方程组和磁场的合成矢量关系,分析了纵向磁场的变化滞后于电流和频率增加时涡流效应更明显的原因,然后利用ANSYSMAXWELL求解了三维瞬态纵向磁场分布。由计算结果可知:在电流变化的过程中,中心区域磁场的变化明显滞后于其他区域。电流峰值时在触头片开槽交错放置的位置有磁场峰值区域,电流过零时中心区域有明显剩磁。当频率增加时,涡流效应更明显,使纵向磁场的磁感应强度值减弱。对中心点,频率提高导致过零时剩磁增加,磁场滞后相位更明显,影响电弧扩散。增加触头片开槽数可以减弱涡流效应,而增加触头杯座槽旋转角,触头中间平面磁感应强度的最大值近似线性增加。并通过实验验证了磁场滞后对真空灭弧室的开断能力的影响。

The characteristic of axial magnetic field(AMF)in vacuum arcing chamber at 400~800Hz is researched in this paper.Firstly,according to the Maxwell's equations and vector synthesis of magnetic fields,the reasons why the AMF lags behind current and the eddy current effect is more obvious with frequency increase are analyzed.Then the 3D transient AMF distribution is solved by ANSYS MAXWELL code.It can be concluded by the calculation as follows:in the current changing process,the change of magnetic field in the central region is slower than that in other regions;there is a peak area of the magnetic field between the interlaced slots at peak current,and there is a significant residual magnetic field in the center area when the current is zero;when the frequency increases,the eddy effect is serious and the magnetic flux density of the AMF decreases,for the center point,with the increased frequency,the residual magnetic field is stronger at zero current and the phase lag is more serious,which will prevents the arc from diffusing;the eddy effect can be reduced by adding the number of slot in the contact blade;the maximum of the magnetic flux density in the middle plane is increased approximately linearly by adding the rotation angle of contact.The influence of magnetic field hysteresis on the breaking capacity of the vacuum interrupter is verified by experiments.