Numerical Simulation of Arcing During Contact Separation in SF6-Filled High Voltage Circuit Breaker

Numerical simulation of thermal arcs in circuit breakers has been challenging, primarily due to the moving surfaces and multi-physics involved in the current interruption process. In this work VizSpark, a fully-coupled electromagnetic and plasma flow solver, to simulate the arcing inside the
$\text{SF}_{6}{-}$
filled circuit breaker. A two-dimensional axisymmetric configuration for a puffer-type
$SF_{6}$
breaker geometry reported in previous research literature is modelled. The moving plug is simulated as an in-motion subdomain, the tulip, auxiliary nozzle and main nozzle are considered to be static. The mean relative speed of contact separation is 4.5 m/s. The sinusoidal current is simulated by choosing circuit parameters that correspond to 2.7 kA current amplitude. We discuss the pressure and conduction current density field during the interruption process. These result show that strong pressure waves form during the short circuit when the arc root changes its position on the underside of the tulip. Further, the arc structure before and after the current zero is discussed.