IEC 60897 Ed. 1.0 b:1987

Describes two test methods, A and B, for assessing the electric strength of insulating liquids in a divergent field when subjected to standard lightning impulses. Method A is based on a step procedure intended to provide an estimate of impulse breakdown voltage under specific conditions. Method B is a statistical test designed to check a hypothesis about the impulse breakdown probability of an insulating liquid at a given voltage level.