INSULATION DETERIORATION DIAGNOSTIC METHOD FOR INSULATING OIL IN ELECTRICAL DEVICES

摘要

PROBLEM TO BE SOLVED: To provide a method of diagnosing deterioration of insulating oil from water saturation estimated from an acid number and water content in oil which are measured using a measured molecular weight of the insulating oil.SOLUTION: An insulating oil deterioration diagnostic method of the present invention involves deriving water saturation, which is water content in oil divided by saturation solubility of water, from results of molecular weight measurement by gel permeation chromatography of insulation oil that fills an electrical device and measurement of acid number and water content in oil thereof. The insulating oil is diagnosed to be more deteriorated as the water saturation reaches closer to 1 or exceeds 1.