Influence of the electronegativity in the breakdown voltage of N2 and SF6 mixtures of circuit breakers

In this work, an analysis of the electronegativity influence in the breakdown voltage of SF
6
and N
2
mixtures, for application in arc extinguishing chambers of circuit breakers is carried out. Computational simulations were performed using the equations proposed by Townsend. Townsend's first and second coefficients and the attachment coefficient were determined proportionally to the amount present in the mixture. Current curves as a function of voltage were obtained to pure gases and for the mixtures. In addition, the coefficient influence was evaluated. The procedure adopted and the simulations were efficient in determining the curves. The influences of the coefficients on the dielectric behavior of the gases were evidenced for the pure gases and their mixtures. Additionally, it can be seen that the mixture composed of 80% of N
2
and 20% of SF
6
showed a higher value of breakdown voltage when compared to that of pure N
2
.