Application of numerical simulation to analyze the force acting on the arc in a vacuum contact

Abstract

Currently, vacuum contacts are installed inside contactors and widely used in underground mines with explosive dust and gases. To ensure safety against electric shock and prevent mine explosions, switching mechanisms are often placed in vacuum arc extinguishing chambers to avoid arcing during power switching. Vacuum circuit breakers are designed to interrupt the flow of electricity when a large current occurs due to a short circuit or other abnormal operating conditions in the electrical network. When a vacuum circuit breaker interrupts the current, metal vapor is released from the contacts and turns into plasma, creating an arc. Arc contraction can increase heat flux and local temperature across the electrodes, leading to surface melting and undesirable effects on equipment lifespan. To overcome this, an axial magnetic field is applied to evenly diffuse the arc across the contact surface, reducing heat density and limiting weld sticking.

This paper applies JMAG software to simulate the electromagnetic force acting on a column arc and the current density in the arc extinguishing chamber. The vacuum arc is modeled using a sequential coupling method of two different fields.