電気設備の絶縁診断における経済性評価

Abstract

Ｏｐｔｉｍａｌ ｃｏｎｄｉｔｉｏｎ ｉｎ ｉｎｓｕｌａｔｉｏｎ ｄｉａｇｎｏｓｉｓ ｆｏｒ ｐｏｗｅｒ ａｐｐａｒａｔｕｓ ｗａｓ ｓｔｕｄｉｅｄ． Ｔｈｅ ｃｏｎｄｉｔｉｏｎ ｆｏｒ ｍｉｎｉｍｉｚｉｎｇ the average maintenance cost per year through the term of guarantee was formulated. Two parameters, i.e., the term of guarantee and tolerance limit of deviation (margin) of the diagnosis, were optimized. the tolerance limit of deviation is related to the tolerance risk ratio. The maintenance cost accompanied with diagnosis was compared with that without performing the diagnosis. In the early stage of the lifetime, the maintenance cost was proved to be lower when the apparatus was continuously used without diagnosis. In the late stage, the cost was lower when the apparatus was replaced without diagnosis. Diagnosis was effective in the midterm between these two stages. It was shown that the term of guarantee should be optimized in accordance with the degree of degradation. A condition suitable for performing on-line diagnosis is also discussed.