Classification of the Distributed Capacitance and Voltage Distribution of V-Arranged Triple-Break Series Vacuum Circuit Breakers

The objective of this paper is to classify distributed capacitance of a V-arranged triple-break vacuum circuit breaker (VCB). The distributed capacitance of the VCB was obtained by a commercial software Q3D. The results suggested that the distributed capacitance can be classified into three types: self-capacitance of the vacuum interrupter (VI), stray capacitance to ground and structural stray capacitance. Therefore, based on the three types of capacitance, the voltage distribution of the triple-break VCB can be simplified from an electric field problem into a circuit problem. The voltage distribution can be analyzed conveniently by control variable method in Matlab/Simulink software. The simulation results indicated that the roles of the three types of distributed capacitance. The self-capacitance of the VI tries to distribute the voltage among the triple breaks uniformly. On the other hand, the stray capacitance to the ground significantly caused the voltage distribution uneven, and the structural stray capacitance slightly caused the voltage distribution uneven.