Simulation on breakdowns in the post-arc phase of a vacuum interruption

Breakdowns in the post-arc phase are affected by a combination effect of both plasma and metal vapor. The objective of this paper is to study the breakdown boundary as a function of plasma and metal vapor density. A fully kinetic PIC-MCC model was developed to study breakdowns in the post-arc phase. Relevant collisions were taken into consideration, and an external circuit was added to the model to make the calculations self-consistent. From the results, we obtained the breakdown boundary in the post-arc phase under effect of both metal vapor and residual plasma. The residual plasma does not play a major role in breakdowns if the density was below 10
¹⁷
m
^-3
. However, if the residual plasma density exceeded 10
¹⁷
m
^-3
, the critical metal atom density for a breakdown steeply decreased with the increase of the plasma density. Therefore, a sufficiently high plasma density gives rise to a higher probability of breakdowns. For this reason, the threshold of metal vapor density could be overestimated if the residual plasma is not considered in the simulations.