杯状纵磁触头纵向磁场滞后时间研究

Study on Phase Shift Time of Cup-type Axial Magnetic Field Contact

用有限元法对杯状纵磁真空灭弧室触头简化的轴对称模型涡流场进行了分析,给出了触头间隙中纵向磁场滞后时间的空间分布,讨论了触头设计参数对纵向磁场滞后时间的影响。计算结果表明,纵向磁场滞后时间沿径向分布的形状近似于凹面朝下的抛物线右半部,在触头边缘处纵向磁场滞后时间随径向位置增大而线性增加。纵向磁场滞后时间沿轴向的分布规律是,靠近触头中心处,纵向磁场滞后时间沿轴向的变化接近一条直线;越靠近触头边缘这种变化越显著,在杯壁中间处呈不规则的“正弦曲线”分布,在触头边缘处呈凹面朝上的抛物线分布。纵向磁场滞后时间与设计参数的关系是:纵向磁场滞后时间随开距的减小而线性增加;随触头直径的减小而单调递减;随触头片厚度的增加而线性增加;触头材料从CuCr50变到CuCr25时纵向磁场滞后时间增幅显著;杯壁厚度和杯高度对纵向磁场滞后时间几乎没有影响。

Eddy current field in cup-type contact of vaccum interrupter with axial magnetic field is analyzed by finite element method with a simplified axial symmetric model. Spatial distribution of phase shift time between axial magnetic field and source current is studied. Afterwards, effects of contact design parameters on the phase shift time are analyzed. It is found that radial distribution of the phase shift time looks like the right part of parabola that has a maximum value. The phase shift time increases linearly with radius at the contact edge. The axial distribution of phase shift time is nearly a straight line at center of contact. But the distribution changes significantly near the contact edge. At middle position of the coil, the axial distribution looks like an irregular sinusoidal curve, and at edge of the contact, the distribution is a parabola with a minimum value. It is shown that the phase shift time increases linearly when contact gap decreases, reduces monotonically with decrease of contact diameter, increases linearly with increase of contact thickness, and increases sharply when contact material changes from CuCr50 to CuCr25. Coil thickness and height have little effect on the phase shift time.