0D Model of Thermal Exchanges at the Opening of an SF6 High Voltage Circuit Breaker

A. Ziani and H. Moulai (Algeria)


Circuit breaker, electric arc, thermal radiation, modelling


This survey aims to simulate the thermal exchanges involved in the cooling phase of an arc plasma in an SF6 high voltage circuit breaker as a function of the time of deionisation. A numerical approach at the neighbourhood of the current zero enabled to study and to follow the evolution of these thermal transfers. The theoretical bases of a new model of arc are then developed, integrating the effect of the thermal radiation implicated in the cooling phase of the thermal plasma. The new arc equation and the heat equation will be coupled with expressions of the three thermal transfer modes (convection, conduction and radiation) to obtain a system of 5 differential equations that will be solved numerically by Runge Kutta method. The results obtained for a default current of 90% of the interrupting capacity in an SF6 circuit breaker (245kV/50kA/50Hz) have been validated by comparison with experimental works.

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