Simulation of Arc Characteristics in Miniature Circuit Breaker

This paper focuses on the numerical investigation of arc plasma behavior in low-voltage circuit breaker with arc-splitting process included. A 3-D simulation model of a certain type miniature circuit breaker product is built and calculated, which is based on magnetohydrodynamics theory. Aside from coupled electromagnetic and gas dynamic interactions being considered as usual, a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc roots. Thus, the arc-splitting process with ferromagnetic plates can be included. Arc motion is described in detail by the temperature distribution. Some interesting phenomena are observed in the simulation, such as the arc root jumping from contact to arc runner, the arc back commutation before splitting into series arcs by metallic plates, new arc root formation in splitting process, and, finally, the arc go across the splitter plates in the chamber. Moreover, the simulation result is compared with experimental result, which shows good agreement.