Distribution of Breakdown Positions in Conditioning Progress Between Plane-Plane Electrodes in Vacuum Under Lightning Impulse Voltage

The purpose of this paper is to determine the distribution of the breakdown locations between plane-plane electrodes in the conditioning progress of the vacuum interrupter. The material of the experimental plane-plane electrodes was CuCr50. The gap length between electrodes was set at 1.0 mm. A standard negative lightning impulse voltage was applied. The breakdown location was decided by the breakdown photo at different perspectives by a high-speed camera, with recording speed of 5.8 × 10⁵ frames/s. The experimental results indicate that the conditioning area covered the entire surface of the contact during the conditioning process. The distribution of breakdown locations was random distribution during the conditioning progress. In the initial conditioning progress of a small vacuum gap, the breakdown locations weren’t only distributed in the region where the electric field was highest. The strength of the electric field might not be the primary key factor that determined the breakdown position distribution during the conditioning process.