d=2�50mm, under non-unform electric fild in vacuum.
Sato et al.[3] discussed the relationship between
breakdown voltage of vacuum gaps and electrode surface
roughness for plate-to-plate electrodes. Several authors
[4-6] studied the area effect on electric breakdown.
However, the breakdown voltage characteristics in high
voltage vacuum interrupters with contact gaps of several
tens of mm are unclear.
The objective of this paper is to understand the
standard lighting impulse voltage breakdown
characteristics of vacuum interrupters with contact gaps
10 to 50mm and how contact parameters inflence the
breakdown characteristics. The investigated contact
parameters include contact diameter 75mm and 60mm,
contact surface roughness 1.6 I m and 3.2 I m, and
contact radius of curvature 6mm and 2mm. The results
could provide some usefu information for high voltage
vacuum interrupters insulation design.