Investigation of transient electric field of vacuum interrupter during current chopping

A circuit including source and vacuum interrupter is taken into consideration as calculated model. The steep-fronted transient over-voltage curve between the contacts of a vacuum interrupter caused by current chopping and reignition is calculated. Three main frequency components of the steep-front transient over-voltage are obtained from the discrete Fourier transform (DFT), which are regarded as boundary excitation. The differential equations of the transient field are established and FEM is adopted to calculate the transient electric field of vacuum interrupter. The distribution curves at representative times are investigated, which are compared with the one in the static field. The electric field intensity distribution curves are also given in this paper. Some distinguishing features of the transient field are also discussed.