Numerical tools for auto-expansion in SF6 circuit-breakers

The authors present the results of a project whose objective was the development of a numerical method for the design and optimisation of circuit breakers. The research concentrated on modelling the arc-gas interactions in a SF₆ auto-expansion circuit breaker. In the chosen modelling, the arc core and the surrounding gas are considered as a continuous medium governed by a single set of equations. The adopted numerical method is a `finite volume´ one. It is adapted to take into account compressibility and real gas properties, Joule losses in the arc, radiative exchanges and energy transport by convection and conduction