Investigation of arc and flow characteristics of self blast type circuit breakers by simulation

Self blast type circuit breakers generate pressure required to interrupt the breaking current, using arc plasma that is ignited between arcing contacts of the circuit breaker. Design parameters have a strong influence on breaking phenomena when SF6 gas is blown out to arc from a thermal chamber. Therefore, we need to know what effects the design parameters of main components such as a nozzle and a thermal chamber have on arc and flow characteristics. In this paper, we developed arc simulation technology using a commercial computational fluid dynamics program. Then based on the simulation, the correlation between arc and design parameters has been investigated. From the study, it was found that the pressure in the thermal chamber was mostly affected by a nozzle throat diameter.