A method to estimate activation energy of power transformer insulation using time domain spectroscopy data

This paper presents a novel technique to estimate activation energy of oil-paper insulation in power transformer from time domain spectroscopy recoded at any given temperature. Existing literatures show that, remaining life of transformer insulation can be estimated if the information regarding its activation energy can be obtained. The activation energy of transformer insulation can be obtained based on its frequency spectrum measured at two different temperatures. However, it is quite difficult to record the frequency spectrum at two different temperatures for the transformers which are operating in the field. Considering the aforesaid difficulty, in the present work, a technique is adopted that can evaluate the activation energy of transformer insulation based on the time domain spectroscopy data recorded at a temperature. In order to investigate the effectiveness, the proposed technique is applied to a test sample having preset moisture content to estimate its activation energy. The estimated activation energy using the proposed technique, is validated with the results obtained using other existing technique. The proposed technique is then applied to several real-life power transformers to estimate their corresponding activation energy. The estimated activation energy for the transformers is used to assess their remaining life.