Modelling of the Interruption Process in SF6 High Voltage Circuit Breaker and Preliminary Study of the Arc Characteristics for Different Gases

Abstract

SF6 is exclusively used as insulation and quenching medium for high voltage circuit breaker because of its high insulation strength and high interruption capability of fault current at present. Therefore it is very necessary to investigate SF6 arc interruption process in high voltage circuit breaker. On the other hand, its greenhouse effect has stimulated the studies for searching environmentally friendly substitute gas. In the paper, a 2-D arc magnetohydrodynamic (MHD) model is presented to one puffer type arc quenching chamber in high voltage circuit breaker firstly. Then, from the view of the difference of medium properties including thermodynamic properties, transport coefficients and radiation characteristic, the arc behavior of SF6, N2 and CO2 gases is simulated based on the model, respectively, taking into account the influence of arc current, chamber pressure. From the preliminary study, good agreement has been achieved with the experimental result, and the validity of the proposed arc model is partially verified. In addition, the effects of medium properties on arc interruption parameters, such as arc radius, arc temperature and arc voltage, are also presented.