Lightning impulse voltage breakdown characteristics of vacuum interrupters with different contact materials

The objective of this paper is to investigate the lightning impulse voltage breakdown characteristics of vacuum interrupters (VIs) with different contact materials experimentally. In the experiments, four 12 kV VIs were investigated. The moving and fixed contact materials were CuW90 and CuCr30. The standard lightning impulse voltages were applied. The results showed that the upper and lower limits of the conditioning processes increased by about 53.5 kV and 15 kV with the contact gap increased from 2 mm to 4 mm. At the same contact gap, the upper and the lower limits of the instantaneous breakdown voltages of the contacts CuW90-to-CuCr30 (cathode-to-anode) were higher than the contacts CuCr30-to-CuW90by about 15 kV. It was also found that there were some large areas of similar melting marks and a large numbers of micro-particles all over the anode contact surface. There were obvious damages distributed all over the cathode contact surface and the features of the damages were dependent on the contact materials.