Numerical analysis of arc plasma behaviour during contact opening process in low-voltage switching device

Abstract

This paper focuses on the numerical investigation of low-voltage arc plasma behaviour with the contact opening process included. A flexible experimental setup with a rotating contact is designed to support this study. Based on the magnetohydrodynamic arc model, the elongation and the commutation behaviour of the arc plasma during the contact rotation progress are simulated. Under the given conditions of the external magnetic field and the contact rotating velocity, the arc motion is described in detail by the temperature distribution. The stagnation together with the following rapid jump of two arc roots is observed by both calculation and experiment. The rapid rise in the arc voltage is mainly caused by the increasing difference between the two arc roots displacement in the moving direction, and the jump instant of the arc root on the moving contact is according to the moment of the maximal voltage value.