METHOD AND DEVICE FOR DIAGNOSING DETERIORATION

PROBLEM TO BE SOLVED: To provide a method and a device for diagnosing deterioration so as to precisely diagnose degree of deterioration in an envelope part of a polymer insulator. SOLUTION: In this method for diagnosing degree of deterioration of the envelope part of the polymer insulator constructed of a core 12 and the envelope 13 arranged around the core 12 and made of silicone rubber, infrared analysis is carried out on the envelope part for finding an infrared spectrum, and in the distribution of the found infrared spectrum, a peak of the envelope is used as a standard peak while a peak of a substance newly produced on the envelope surface because of deterioration is used as a reference peak, and then, using a ratio of the reference peak to the standard peak as an index, diagnosis of the degree of deterioration is carried out. The deterioration diagnosing device is constructed of a portable infrared analyzer having a computing unit performing this deterioration diagnosing method and an optical fiber installed to the tip of the infrared analyzer and provided with an optical crystal for infrared analysis.