Evaluation of efficient electrode conditioning method for vacuum interrupters

This work describes an efficient conditioning method to achieve 400 kV of lightning impulse withstand voltage for the vacuum interrupter rated at 84 kV by applying commercial frequency voltage. As the first step, we measured the electric potential of the arc shield by reproducing the electric field when the interrupter was installed in the gas-insulated switchgear. The electric potential was about 40% of the applied voltage. Using the measured potential, the electric field of the vacuum interrupter for the lightning impulse voltage of 400 kV was simulated. Then the conditioning system was determined so as to satisfy the insulation design criteria for each part of the electrode. The intermittent discharge during voltage application was stopped within one minute. With this conditioning, we succeeded in withstanding lightning impulse voltage of 400 kV or more. This conditioning achieved to eliminates the conventional conditioning by switching arc and applying lightning impulse voltage. As a result, the time required for conditioning was drastically reduced.