One-dimensional hydro-kinetic modelling of the decaying arc in air–PA66–copper mixtures: II. Study of the interruption ability

Abstract

A one-dimensional hydrodynamic model coupled with a chemical kinetic model has been developed to study arc extinction in a low-voltage circuit breaker (LVCB). In this second part, the calculation assumptions and the fundamental equations of the stationary and transient hydrodynamic models and of the kinetic module are presented together with the boundary and initial conditions. Radial temperature profiles and radial velocity profiles obtained from the model are shown during arc decay. The influence of the mixture (in particular the presence of copper and organic vapours due to electrode and wall erosion) and of the effect of chemical non-equilibrium on the interruption ability are highlighted through the calculation of the conductance. As departures from chemical equilibrium are weak, they have no significant effect on the conductance evolution of the decaying arc. In contrary, the presence of metal and especially organic vapours (respectively, responsible for an increase in the electrical conductivity and for the appearance of dissociation peaks in the thermal conductivity at low temperatures) has a significant influence on the conductance of the extinguishing plasma.