Theoretical description of the current interruption in hv gas blast breakers

A theoretical model is derived Which is able to describe the current interruption in hv gas blast circuit breakers. The model is based on experimental observations of the relevant physical phenomena. The guidelines for establishing the equations were to describe these relevant effects according to present knowledge as good as possible and to keep the model as simple as possible. Two constants describing the intensity of the turbulence were adjusted to get agreement with measured data. The model then describes correctly the dependence of the limiting curves for thermal reignition on current and on pressure. The difference between air and SF6is also described correctly by changing only the material properties in the model. Besides these results curves for the dependence of the post arc current on pressure and switching current are calculated.