Analysis of interrupting characteristics for O-CO operation of self-blast type circuit breakers

High voltage circuit breaker should interrupt short circuit currents not only under O operation for minimum arcing time but also under O-CO operation for maximum arcing time. In this study, analysis for act extinction characteristics under the O-CO operation for maximum arcing time has been conducted with the self-blast type high voltage circuit breaker. For the analysis of arc characteristics, a commercial fluid dynamics(CFD) program was used. The theoretical analysis results show that the arc extinction performance of the second O operation is severely affected by the conditions of remaining thermal gas in the thermal expansion chamber after the first O operation. This means that O-CO process analysis is inevitable for the correct evaluation of the interruption performance of O-CO operation for maximum arcing time in the self-blast type high voltage circuit breaker.