Discharge pattern discrimination for composite insulation system in vacuum interrupter

For the development of vacuum interrupters (VI) for their higher voltage application in power transmission systems, the investigation and clarification of discharge characteristics in a composite insulation system with a shield (floating) electrode and a solid insulator in vacuum are necessary. The discharge phenomena and patterns at internal insulation failures in VI are complex and various. In this paper, based on the discharge development characteristics, we proposed a novel discrimination method of the discharge pattern in vacuum. In addition, we executed iterative verification tests of the proposed discrimination method by using a model which simulates the insulation system of VI. The results revealed that 50 discharge events with 5 patterns were discriminated in the total 54 tests. Therefore, the discrimination success rate reached 93%, and the effectiveness of the proposed discrimination method for discharge patterns in VI was confirmed.