Diagnosis of Oil Immersed Transformers by Colorimetry of Insulating Papers

Abstract

Power transformers have been expected to work with safety and reliability during the long period over 30 years. Life expectancy of transformers depends upon the degree of deterioration of insulating materials, particularly conductor insulating paper. Many attempts have been made in recent years to estimate the degree of deterioration of transformers, no diagnostic techniques have been developed in practical use because of the difficulty to take the service conditions into account.
It is well known that the color of materials changes according to its deterioration and colorimetry has not been studied on material deteriorations. According to the recent advances in instrumentation and data processing equipment, the color of materials has become easily to be measured qualitatively. So the basic investigation on colorimetry of insulating papers has been made to make the applicability to power transformers clear. Test results showed the strong correlation between the color difference and the deterioration of insulating papers. This paper mentions the effect of materials of papers and impregnating oils on colorimetry.