Interruption capability of a fast vacuum circuit breaker with a short arcing time

With a capacity increase of the power system, the fault current increases very quick and it becomes a threat for other equipment in the power system. Vacuum interrupter combined with an electromagnetic repulsion mechanism can achieve a very fast opening operation. It can be designed to interrupt the high fault current approaching a zero-crossing point so that the interrupting capacity can be enhanced. The objective of this paper is to investigate the interruption capability of a fast vacuum circuit breaker with a short arcing time. High speed electromagnetic repulsion mechanism was used to drive the vacuum interrupter. To achieve a quick interruption, the key parameters that influence the opening velocity were investigated by experimental and simulation methods. The results show that the average opening velocity can reach 5 m/s and the opening time can be within 500 μs. A prototype of the fast vacuum circuit breaker was thus set up. Interruption test was done to test its interruption capability with a short arcing time. The test results show that the fast vacuum circuit breaker prototype can achieve reliable interruption with a short arcing time approaching 3 ms.