When short current is interrupted in three-phase vacuum interrupter in switchgear, the “U”-type loop composed of external busbar, conductive rod, and vacuum interrupter, and its adjacent phases will generate external actual transverse magnetic field (EATMF) in the interrupter. The existence of EATMF will deflect the vacuum arc, which will affect the breaking performance of vacuum switch. In view of this situation, this article establishes two kinds of electrode system simulation models considering and not considering EATMF. The simulation results show that EATMF is not uniformly distributed in the interelectrode region, but is stronger in the contact cup edge area outside the “U”-type loop, weaker in the “U”-type loop, and mainly affects ${B} _{x}$ . In different short-circuit cases, EATMF is also different due to the difference of phase distance and short current. In the case of three-phase short circuit, the magnetic field in the interelectrode region of the middle phase is most significantly affected by EATMF. EATMF is closely related to the structure size of vacuum switch. By changing the structure size of vacuum switch (e.g., phase spacing ${d}$ , conductive rod length ${h} _{1}$ , ${h} _{2}$ ), EATMF can be weakened to some extent.

中文翻译：

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三相结构横向磁场AMF真空电弧开关中磁场的数值研究

当开关柜中的三相真空灭弧室短路电流中断时，由外部母线、导电棒和真空灭弧室及其相邻相组成的“U”型回路会在灭弧室中产生外部实际横向磁场（EATMF） . EATMF的存在会使真空电弧偏转，从而影响真空开关的开断性能。针对这种情况，本文建立了两种考虑和不考虑EATMF的电极系统仿真模型。仿真结果表明，EATMF在极间区域分布不均匀，但在“U”型回路外的接触杯边缘区域较强，在“U”型回路中较弱，主要影响 ${B} _{x}$ . 在不同的短路情况下，由于相距和短路电流的不同，EATMF也不同。在三相短路的情况下，中间相极间区域的磁场受EATMF影响最为显着。EATMF与真空开关的结构尺寸密切相关。通过改变真空开关的结构尺寸（如相距 ${d}$ , 导电棒长度 ${h} _{1}$ , ${h} _{2}$ )，EATMF可以在一定程度上减弱。