Abstract
Synchronous switching controller (SSC) for gas circuit breakers (GCB) has been developed. SSC is able to close and open a GCB at the appropriate point on wave for minimizing the switching surges. This paper proposes the new synchronous switching algorithm to minimize the control delay time, and the control error for the desired point on wave. New algorithm for (1) detecting voltage and current zero crossing points and (2) predicting the next operation time of GCB is introduced. 145kV GCB with SSC built in new algorithm has been tested several condition. SSC performed well from-30 degrees C to 60 degrees C at various control voltage condition and the standard deviation from the taget phase is within 0.5msec. And the closing at two target points with voltage zero and peak works well in a capacitive load circuit at 145kV.
