Abstract:

Anode activity has important influence on the vacuum interrupter when the vacuum interrupter breaks large current.Under the action of large current arc, the anode surface temperature gradually increases. When the temperature reaches the anode material melting point, the anode surface begins to melt and forming a molten pool. The evaporation of metal vapor from the molten pool will enter the contact gap of the vacuum interrupter, possibly reigniting the arc again, thus causing the failure of breaking.In this paper, a two-dimensional fluid model and a heat transfer model for vacuum interrupter are established. The phenomena of anode erosion, phase change and the change of anode temperature with time are studied. The heat transfer of ions and electrons to the anode and the loss of anode in the arc are taken into account, and the melting front is tracked by using Stefan function. The process of anode phase transition and temperature distribution are simulated to provide theoretical basis for the accurate evaluation of interrupter breaking ability.

Key words: Vacuum interrupter, vacuum arc, anode erosion, surface temperature