Correlation of breakdown gradients in compressed air and SF6 for nonuniform fields

In a previous paper
¹
the authors have described the so-called “empirical” and “semiempirical” methods of estimating minimum breakdown (sparkover) voltages for gas insulated systems. The authors' special interest is with systems insulated with compressed air or SF
6
at several bars pressure as might be found in high-voltage gas insulated metalclad switchgear
^2,3
and associated equipment. The above techniques can be used at the design stage to ensure that the statutory high-voltage test levels, including 50 Hz and lightning impulse, will be attained in practice.