杯状纵磁真空灭弧室三维涡流场仿真

对杯状纵磁真空灭弧室触头建立了与实际触头结构完全一致的有限元分析模型,模型中把电弧弧柱处理成圆柱形金属导体.对模型用有限元法进行了三维涡流场仿真.仿真结果表明,考虑电弧以及杯和电弧的涡流效应后,在电流峰值时,触头片中电流密度最大值变大;触头片上槽一侧的纵向磁场比另一侧强;磁感应强度B矢量在触头表面上的分布呈"旋涡"形状,其纵向分量在触头中心较大,越靠近触头边缘越小,而横向分量则增大;电流过零时,与未考虑电弧以及杯和电弧的涡流效应时的计算结果相比,触头间隙中心平面上及触头表面上的纵向磁场分布变为"帐篷"形状,纵向磁感应强度最大值也变大.在触头开距中心处纵向磁场较强且纵向磁场滞后时间也相对较长.

Analysis of 3D eddy current field in cup-type axial magnetic field vacuum interrupter

A finite element analysis model that is the same as an electrode structure of a commercial cup type axial magnetic field vacuum interrupter is built up. An arc that is treated as a cylinder conductor is included in the model. Eddy current field generated by an ac current passing the electrodes is analyzed. It is shown that maximum value of current density in contact at current peak becomes higher when the arc is considered and the eddy current influence in coils and the arc take effect. It is also found that the axial magnetic flux density is much higher on one side of a contact slot than on the other side at the current peak. B vector distribution on contact surface is also shown. It looks like a swirl. The axial component of B vector is higher in middle part of contact and it becomes lower near contact edge, where the radial component of B vector becomes higher. It is shown that axial magnetic flux density distribution on middle gap plane and contact surface changes to a tent shape at current zero when the arc is considered and eddy current influence in coils and the arc take effect, which also makes maximum axial magnetic flux density higher. It is pointed out that contact center is such a position that both phase shift time and axial magnetic flux density are high.