An axisymmetric finite element model of 72.5 kV vacuum interrupter is established to analyze the potential and electric field distributions as well as the factors influencing the distributions.Subsequently

the potential and electric field distributions are calculated

the area effect of vacuum breakdown is investigate

and the effects of main shield’s structure and size and multiple shields on the electric field distribution inside the vacuum interrupter are analyzed.The results indicate that: The potentials between moving and stationary contacts and between contacts and shield change obviously

and the electric field distribution inside the interrupter is non-uniform;With the increase in contact gap distance

contact radius

and curvature radius of contact chamfer

the active area on contact surface enlarges

but the maximum electric field strength inside the interrupter reduces;The increase in radius and length of the main shield leads to decrease in electric field strength at both ends of the shield

and the internal electric field distribution gets more uniform if there are multiple shields in the vacuum interrupter.This study may provide a reference for optimization design of high voltage vacuum interrupter.