Electrical breakdown of N2O, SF6 and N2O/SF6 mixtures

Abstract

Measurements of static breakdown voltages were made for SF6 and N2O/SF6 mixtures containing between 1% and 50% SF6 by volume for values of Nds within the range 1023 < Nds < 1024 m−2 (where N is the gas number density and ds the sparking distance). These results, together with earlier data on N2O, show that the departures from Paschen's law become smaller as the percentage of SF6 in the mixture is increased over the range from 0 to 10% becoming negligible above about 6%. These results agree with predictions made on the basis of the ion-molecule reactions occurring in these gases. The dielectric strength of a 37% mixture was found to be about 83% of that for SF6 alone, and it is shown that, for this mixture, an increase in total pressure of about 20% gives the same dielectric strength as SF6 alone with a saving in cost of about 50%.