The influence of electrode material on delayed discharges in vacuum interruptors

In this paper, the influence of contact materials on late discharges in vacuum switching devices was investigated. Experimental results show that the HV withstand capability of contact materials has a strong influence on the frequency of late discharges in vacuum switching devices. The addition of a small amount of W and Co into the CuCr alloy increases the voltage withstand significantly, resulting in a reduction of the frequency of late discharges by as much as 50%. Therefore, an efficient approach to decrease the frequency of late discharges is to increase trie HV withstand of the contact materials.