Measurements on new transformer insulation

MEASUREMENTS OF THE power factor and resistance characteristics of transformer insulation are being used increasingly for the control of quality in the factory. The usefulness of these measurements is based on the fact that they are affected by any ionizable impurity such as water, low molecular weight acids from oil deterioration, soluble salts, and other contaminants. In the factory, the principal use for these measurements is the detection of moisture. This moisture has the effect of increasing the insulation power factor, decreasing the insulation resistance, and decreasing the dielectric absorption effect.