Effect of Micro-particles Impact Phenomena on Contact Surface in High Voltage Vacuum Interrupter after Conditioning

The objective of this paper is to determine the effect of the micro-particles impact phenomena on the contact surface in high-voltage vacuum interrupter after conditioning. The morphology of the erosion region in the contact surface after conditioning was determined. The fractal dimension of the scanning area was calculated. A two-dimensional axisymmetric model was constructed to obtain the maximum electric field strength on the contact surface, and finally using the smoothed particle hydrodynamics (SPH) to simulate the micro-particle impact phenomenon. The results indicate that there were large number of micro-protrusions in the erosion region, with the height ranged from 20 to 180 $\mu$m. The microscopic electric field on the surface of the rough contact is enhanced by the micro-protrusions, which was higher than $1\times 10^{8} {\mathrm{V}/\mathrm{m}}$. The field enhancement factor $\beta$ at the maximum point was equal to 14.1. The irreversible crater may be formed on the electrode surface, in the condition that the micro-particle impacts was at high speed.