Simulation of arc-electrode interaction using sheath modelling in SF₆ circuit-breakers

The transition layer, or sheath, located at the interface between the electrode and the electric arc plasma in circuit-breaker arcs is modelled and integrated into software for the simulation of arcs. The sheath model includes the equation of the continuity of electrons, the generalized Ohm's law and the equation of conservation of total energy. The latter equation takes into account Joule heating, the radiation from the arc and phenomena on the surface of the electrode such as thermionic and radiative cooling by thermal emission. The resulting arc model can predict electrode and arc temperatures simultaneously.