Interruption Performance of a 40.5kV Vacuum Circuit Breaker Used for the Fault Current Limiter

The vacuum circuit breakers(VCBs) are commonly used in the medium and lower voltage power systems. With the requirements of current limiters, the interruption characteristics of the vacuum circuit breaker need to be improved. As to obtain the relationships between interruption characteristics and arcing extinguishing chamber key structures, tests are adopted to a 40.5kV vacuum circuit breaker in this paper, and lots of calculations are carried out for optimization of electromagnetic field. It is shown that for the application in current limiters, contact structures and coil must be designed and optimized for obtaining larger magnetic force so as to interrupt the arc under the conditions of higher DC component and shorter arcing time. Testing results reveals that the interruption behaviors are affected by the polarity of the vacuum circuit breaker, it is harder for interrupting when polarity is positive, and the interruption performance of the VCB is decreasing because of the electrical inductance existing in the current limiter.