Spacer Flashover in Compressed Gases

Surface flashover studies of cylindrical spacers are carried out in SF6-N2 and other SF6-gas mixtures in a uniform field. In the presence of the spacer, the value of the surface flashover voltage is typically found to be lower than the corresponding breakdown own voltage of the gas gap without the spacer. It is experimentally found that this reduction in the breakdown voltage depends to a large extent on the dielectric constant of the spacer material, the type of end-contact between the spacer and the electrode surface, the surface condition of the spacer, the content of SF6 in the gas mixture, and the gas pressure. re. From these experimental results, an empirical expression is developed for the first time to predict in compressed gases. The calculated values of the flashover voltage show a good agreement with the measured values of the author as well as with those previously published in the literature.