Abstract :
A theoretical investigation of the influence of strongly charged macro-particles, on the breakdown of vacuum circuit breakers, is presented. Particle charging is shown to occur during the post arc current phase, in the growing plasma sheath. The subsequent trajectories of these particles during the recovery voltage phase is studied. Their influence on the cathode electric field and field emission is studied. Finally, the trajectories of emitted electrons are studied and breakdown probabilities discussed. The model proposed gives new insight into the statistical nature of post arc breakdown in vacuum circuit breakers and, especially, late breakdowns
