Research on Development Process of Post-arc Sheath for Main and Auxiliary Gap Series-Connected in High-Voltage Vacuum Interrupter

Vacuum circuit interrupter as a kind of fluorine-free environmental protection switch is widely used in the field of power distribution, However, due to the saturation effect of long vacuum gaps, it is difficult to break through high voltage levels. To this end, this article proposes a high-voltage level main and auxiliary gap series integrated vacuum arc extinguishing chamber, where the auxiliary gap assists in insulation and arc extinguishing of the main gap. Based on the PIC-MCC (Particle In Cell Monte Carlo Collision) model, the dynamic dielectric recovery characteristics of the main and auxiliary gap series vacuum arc extinguishing chamber after arc are studied. The arc process is analyzed from the perspectives of arc current, arc electric field, sheath development, and particle transport dynamics, and the development laws of electrical parameters and microscopic particle motion processes are obtained. The results indicate that when the voltage division between the main and auxiliary gaps is 2:1, the electric field strength borne by the sheath during development is relatively small, with a maximum electric field strength of 7.12 × 105 V/m.At the same time, the voltage self-sharing can reduce the arc current, optimize the arc electric field distribution, and accelerate the development of the arc sheath layer. This article provides some guidance for the design of ultra-high voltage level vacuum arc extinguishing chambers.