Improvement of Cu-Cr electrode surface under impulse voltage conditioning in vacuum

As vacuum attracts attention from a viewpoint of high insulation performance and environmental-friendliness, vacuum circuit breakers (VCBs) are expected to develop into higher voltage level. In this paper, we discuss the relations between the surface state and the conditioning mechanism of Cu-Cr electrode during impulse voltage application process in vacuum. The experimental results showed that the deposited layer at the cathode surface was formed by the anode material due to the impulse voltage application process. We finally clarified and concluded that under impulse voltage application process, characteristics of the cathode surface are changing to those of the anode material, and anode material could determine the final states of conditioning process.