Conditions pertaining to the influence of electrode surface roughness upon the insulation strength of compressed SF6 systems

On the basis of a series of experimental investigations reported in the literature, electrode microscopic surface roughness was dismissed as a factor influencing breakdown levels in compressed SF6, irrespective of field non-uniformity. This conclusion appears to be tenable if one restricts observations to the investigations in question. In the present communication, we contend that the scope of these studies formed an insufficient basis on which to invoke such a general conclusion. To clarify this contention, the role of surface roughness in relation to the breakdown characteristics of compressed SF6 is recalled and its domain of influence brought into focus.