直流开断中触头边缘弧根停滞现象及影响因素研究OA

The evolution of arc root has an important effect on the switching efficiency of DC air circuit breaker.Based on the magneto-hydro-dynamics(MHD)model,the essential cause for the arc root stagnation of the contact edge was simulated and analyzed.The effects of the external magnetic field and breaking speed for the arc root stagnation of the contact edge were obtained.The results show that the transfer of the arc root from the contact to the arc runner is completed through breakdown.The arc root stagnation of the contact edge is formed because the arc runner has not reached the breakdown condition before the arc root transfers.With the increase of magnetic field intensity,the arc root stagnation time of the contact edge decreases,and the ability to shorten the arc root stagnation of the contact edge becomes weak,eventually tends to be saturated.At the initial stage of arcing,increasing the contacts breaking speed within a certain rang is conducive to reduce the arc root stagnation time.However,excessively increasing the contacts breaking speed has a weak effect on reducing the arc root stagnation time under the influence of Lorentz force and airflow field.