Low- Voltage Arc Interruption Computation: the Effect of Stefan Flow

Low-voltage circuit breakers provide essential protection for industrial and residential power distribution, by taking advantage of cathode drop to force current zero. This is accomplished by using the magnetic force and pressure on the arc as the contacts open to push the arc towards a stack of steel plates which break the arc into sub-arcs and thereby multiply the number of cathode drops. As the fault current can be high, substantial energy can be dissipated, which results in interactions among the arc and solid materials: ablation of wall materials. Comprehensive CFD/MHD studies have been conducted for arc running and splitting, although an important mechanism in arc breaking computation, the effect of Stefan flow induced by species generation, has not been considered. In this work, we report out a simulation approach for taking into account the effect of Stefan flow, particularly for the breakers with highly gasified wall materials. This approach accounts for the initial velocity of added-in species from the surface of the polymer wall and electrodes' surface, which will largely influence the flow field and the property of plasma mixture. The ability of conducting computation with considering Stefan flow effect will further enhances the accuracy of arc simulation in low-voltage circuit breakers.