Electrode area and stressed volume: Two apparent effects of large-volume oil insulation

Analysis of the dielectric degradation observed in large-volume oil insulation revealed that the phenomenon can be interpreted in terms of an apparent effect of either the electrode area or the stressed volume. A semi-empirical method was developed for quantitative evaluation of the dielectric degradation of large-oil-volume insulation. The method applies the weak-link theory to an oil gap, assuming an apparent effect with a unit element of known breakdown probability distribution determined from experimental data.