Development and application of vacuum circuit breaker model in electromagnetic transient simulation

Vacuum circuit breakers (VCB) have excellent interruption and dielectric recovery characteristics, and can interrupt the high frequency currents, which result from arc instability. The interruption of these high frequency currents leads to multiple reignitions when the breakers are opening and severe voltage escalations under certain network conditions. The main aim of the paper is to model the vacuum circuit breaker in PSCAD that replicates the original breaker characteristics. The model developed simulates the occurrence of these transients. The model incorporates the random nature of arcing time, current chopping, dielectric strength and the quenching capability of the breaker. The developed breaker model for 3-/spl Phi/ VCB is implemented in a practical circuit employing switching off an arc furnace transformer and the results are presented.