Mechanism Research Of The Vacuum Online Detection Of Vacuum Circuit Breaker Based On The Shield Potential Method

Although the shield potential method is one main exploration method in all vacuum online measurement methods of vacuum circuit breaker, it has not been applied in high vacuum measurement in practice so far. In this paper, the relationship between relative permittivity and air pressure is provided, and 2-D electric field distribution of vacuum circuit breaker under various vacuum levels were carried out with the aid of finite element analysis tool. The analysis results show that the vacuum degree of vacuum circuit breaker keeps a certain corresponding relation with the shield electric potential and it can be reflected by measuring the electric potential around the breaker. Besides, the change of breaker external potential is very weak in the vacuum 10(-2)Pa above, while it gradually becomes obvious in the vacuum 10(-2)Pa below. The change rule of breaker electric potential under different vacuum is provided by the analysis results which have certain guiding significance for online measuring vacuum degree of vacuum circuit breaker based on the shield potential method.