Inhomogeneous field breakdown in GIS-the prediction of breakdown probabilities and voltages. I. Overview of a theory for inhomogeneous field breakdown in SF6

Inhomogeneous field breakdown in SF₆ has been investigated, and a theory has been developed which predicts the breakdown voltage for fast-rising (rectangular) waveforms applied to arbitrary electrode geometries and gas pressures. This theory facilitates the analytical design aspects of many GIS components where previously, engineering judgement and development testing were necessary. It is suggested that extensions of the theory, will permit breakdown voltage prediction for an arbitrary surge waveform, which will facilitate the assessment of test waveform efficacy and the development of a more reliable field, factory, and type tests