Influence of the Shapes of Arcing Contacts on Prestrike Phenomenon in SF6 Circuit Breakers

Prestrike phenomenon in circuit breakers (CBs) can cause electromagnetic transients in power systems. Therefore, the investigation of this phenomenon has considerable importance. The scope of this paper is to investigate the effects and importance of arcing contact shape on the prestrike in SF
₆
gas CBs. In order to simulate the prestrike with high accuracy, a multi-physics model is developed precisely. In this model, equations of motion of the SF
₆
gas, the electric charge conservation equation, turbulent equations, heat transfer equation in fluids, and the governing equations of an electric circuit in which the CB works are considered simultaneously. The numerical study is performed on a 72.5-kV single pressure puffer type SF
₆
CB. Three different types of arcing contacts are investigated in this paper. Numerical results show that the arcing contact shapes have an important effect on the prestrike in gas type CBs.