Calculation and Analysis of Transient Electric Field of 10kV Outdoor Vacuum Circuit Breaker under Lightning Impulse

A time-domain mathematical model of electric field is introduced to calculate the transient electric field of the outdoor vacuum circuit breaker. The lightning impulse voltage is expressed by double-exponential function, which is regarded as a component of the boundary excitation in solved region. Under lightning impulse voltage, the potential distributions curves of external insulation are calculated when the outdoor vacuum circuit breaker is in the closed state and the other potential distributions curves in vacuum breaker and on external insulation are also calculated when breaker is in the open state. Electric intensity distribution curves on the surface of external insulation and contact are also shown in this paper. The maximum of intensity in solved region is also given. Some distinguishing features of the transient field are also discussed. It is essential for vacuum circuit breaker insulation design