Extremal area effect for large-area electrodes for the electric breakdown of transformer oil

The 60-cycle breakdown strength of good quality transformer oil has been shown to depend upon electrode size for a physical area ratio of 20 to 1 and for an additional ratio of 400 to 1 by means of a “group-of-minima” inference (1). The extremal nature of the breakdown distribution found to exist by these tests was also found to apply to impulse breakdown (2).