Post-arc period of vacuum circuit breakers: New 2D simulation and experimental results

A 2D model of sheath expansion and plasma decay for transient recovery voltages has been developed in order to improve understanding of the physical phenomena related to the post-arc phase. This new model considers charged and neutral particles produced during the arcing period, electrode evaporation and also the collisions between charged species and metal vapor atoms. New 2D simulation results are presented for 20 mm diameter copper electrodes for various electrode surface temperature profiles. Sheath evolution, residual plasma density, post-arc current and electric field distribution are presented. Experimental investigations were carried out in a specially designed set-up which allows measurement of post-arc current and plasma sheath dynamics. Electron temperature and plasma density have also been measured experimentally. The comparison between the simulation data and experimental results are presented.