Stochastic regularities of electrical breakdown initiation in transformer oil

The experiments on breakdown in transformer oil at small gaps between the hemispherical electrodes under the linearly increasing AC voltage were carried out. The stochastic regularities of breakdown initiation were studied using previously proposed theories. Analytical expressions were derived that allowed the authors to reconstruct the probability density function /spl mu/(E) for transformer oil using the experimental data of present and previous work. The probability density functions of the breakdown initiation for the transformer oil are determined at various parameters of experiment (radius of curvature of electrodes, gap length between them and the growth rate of the amplitude of AC voltage). The conception of dynamic electric strength originates from the stochastic approach proposed by averaging the breakdown voltages over the probability distributions.