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With the advantages of environmental protection, small size, and light weight, the vacuum circuit breaker has been widely used in power systems. At present, it is developing toward the direction of high voltage and high current. In this paper, the magnetic field simulation model of a cup-shaped axial magnetic contact system is established, and the actual magnetic field data in the arc area are obtained as the boundary conditions, and then a three-dimensional steady-state magnetohydrodynamic model of the vacuum arc is established. The plasma parameter distribution characteristics in the vacuum arc area are studied by changing the number of slots in the contact plate, the angle of the contact cup chute, the length of the slot in the contact plate, and the central process hole. On this basis, a new type of embedded axial magnetic contact system including an embedded magnetic ring and a reverse contact cup is proposed, and the influence of changing the angle and number of inclined slots of the embedded contact cup on the arc distribution characteristics at the peak current and current zero is further studied. The simulation results show that the new structure contact is helpful to the breaking capacity of the vacuum switch and has a guiding significance for the design of the vacuum circuit breaker. By comparison, our simulation results have the same trend with the experimental results of other researchers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]