Investigation on chemically non-equilibrium arc behaviors of different gas media during arc decay phase in a model circuit breaker

The arc behaviors of different gas media, including air, N-2 and O-2, during the current-zero period in the circuit breaker were investigated based on a non-chemically equilibrium (non-CE) model. The arc behaviors during the decay phase by the non-CE model were compared with those by the local thermally equilibrium (LTE) model. In the LTE model, since the thermodynamic and transport properties of air are quite similar to those of N-2, the results indicate that the arc behaviors in these two gases are quite similar. On the contrary, the results by the non-CE model indicate that the arc behaviors of the air could be quite different from those of N-2, which is caused by the different reaction processes due to the existence of both the N and O element in the air. It can be concluded that during the current-zero, the reaction process greatly influences the arc decaying behaviors, which cannot be considered in the convectional LTE model. Therefore, the non-CE model is very important to predict the arc behavior during the arc decay phase, and the validity of the non-CE model was further confirmed by the laser Thomson scattering in different gas media.