Research on Sheath Development of Vacuum Circuit Breaker Based on Continuous Transition Model

The DC circuit breaker technology is one of the key technologies to build multi-terminal DC transmission network. Active DC vacuum circuit breaker (DCVCB) has become the research object. Based on the continuous transition model(CTM) and variable-step 4th-order Runge-Kutta method, sheath development stage during the post-arc dielectric recovery has been simulated and analyzed. Then the influence of major variables, including arc energy, contact erosion rate, and axial magnetic field between contacts, on sheath growth of post-arc dielectric recovery have been analyzed. The results show that the sheath thickness grows exponentially with time, and higher arc energy and contact erosion rate will result in larger initial ion density, longer ion decay time and slower sheath development. The stronger axial magnetic field will reduce initial ion density and promote sheath growth.