Analysis of the breaking capacity of auxiliary switch for the operation control of high-voltage circuit breaker

The auxiliary switch, which is used in high voltage circuit breakers, can be used to control the close and open commands. The breaking capacity and electrical endurance are two important indexes of circuit breaker reliability. This paper proposed the mathematic model of the arc chamber of FK-type auxiliary switch, and deduced the mathematical condition of dielectric breakdown after current zero by simulating its inner electric field intensity distribution. The arc-quenching chamber is optimized to average electric field and to increase its breaking capacity. Then the target of improving electrical is accomplished.