Evaluation of the interruption capability of SF6 gas mixtures based on one-dimensional arc model


SF6 gas mixtures are one of the popular SF6 alternatives. For the purpose of quantitatively evaluating the arc extin-guishing performance of SF6 mixtures, this paper combines one-dimensional arc decaying model and Boltzmann equation to divide the whole arc extinguishing process into thermal recovery stage, pre-dielectric recovery stage and post-dielectric recovery stage, which are evaluated by three parameters, namely thermal recovery rate, pre-dielectric recovery rate and post-dielectric recovery rate, respectively. The harmonic mean of the above three parameters is calculated as the harmonic average recovery rate to evaluate the arc extinguishing performance of SF6-N2, SF6-CO2, SF6-CF4, and SF6-Air mixtures. Based on the proposed method, the effects of SF6 proportion, buffer gas type and gas pressure on the interrupting performance of the SF6 mixtures are preliminarily investi-gated. The results show that the overall arc quenching ability of the gas mixtures presents a decreasing trend as the lowering of SF6 proportion. Among the four gas mixtures with SF6 proportion ranging from 10% to 50%, the SF6-N2 gas mixture has the best interrupting performance, followed by SF6-Air, SF6-CO2, and SF6-CF4 succes-sively.

Electric Power Engineering Technology