Study on Arc Root Stagnation of Contact Edge and the Erosion Mechanism of DC Breaking Process

This paper investigates the stagnation phenomenon of the arc root at the contact edge and the mechanism of contact erosion during the DC interruption process through numerical simulation. An improved level-set model was developed to simulate the two-dimensional air arc erosion and splashing and a magnetohydrodynamic(MHD) model considering energy transfer between the arc and the contact was established. Using a real heat source, the study comprehensively analyzed the heat transfer, mass transfer, and fluid flow during the arc root stagnation process at the contact edge. The results indicate that during the arc root stagnation-transition process at the contact edge, increasing the interruption speed and the magnetic induction intensity of the blowout magnetic field shortens the stagnation time and reduces the degree of contact edge erosion. However, once the interruption speed reaches 5 m/s or the magnetic induction intensity exceeds 50 mT, the transition speed does not significantly increase, and the erosion severity gradually intensifies when the magnetic induction intensity surpasses 50 mT.