Magnetic field synergistic control mechanism in vacuum arc ignition: from single-field regulation to multi-field cooperative design

Abstract

The magnetic performance of vacuum circuit breakers is of vital importance for their stable operation. This paper systematically investigates the mechanism and performance boundaries of magnetic control during the vacuum arc combustion process. The traditional single magnetic field system has its inherent limitations: although the axial magnetic field (AMF) effectively controls the stability of the plasma, its performance deteriorates due to the phase lag and field uniformity loss caused by high-frequency currents and large contact gaps. The transverse magnetic field (TMF) drives the arc movement through the Lorentz force to prevent local heat accumulation on the contact surface, but it is still prone to arc stagnation, slot bridging and other adverse phenomena. To overcome these limitations, this paper proposes a composite field design framework based on spatial coordination. Spatially, the AMF provides global plasma homogenization, creating a stable medium for the TMF to promote directional energy dissipation. Temporally, emphasis is placed on dynamic field matching and coordinated mechanical responses to counteract phase lag. Additionally, this paper clarifies the core physical mechanisms of this composite magnetic field, including the coupling control of plasma dynamics and the electrothermal interaction between the arc electrodes. Engineering verification shows that this coordinated design enhances the interruption capability in high-voltage and direct current applications. Ultimately, these findings indicate that transitioning from single-field adjustment to multi-field coordinated design is not only an optimization but also a key requirement for improving the performance of vacuum interrupters and addressing complex multi-physics challenges under extreme operating conditions.