Use of Dielectric Spectroscopy to Estimate the Condition of Cellulose-Based Insulation

Abstract

Assessment of the power transformersinsulation condition is a permanent concern forcarriers and distributors of electrical energy.Different methods for their monitoring and diagnosiswere developed in recent years. The aim of this workis to present the basis of the dielectric spectroscopymethod and the first results obtained in time-domainand in frequency domain that permit to estimate themoisture content in pressboard. At the end, thepossibility to use this method for off-line and on-linetransformer monitoring is analyzed.

Keywords

• dielectric spectroscopy
• cellulosic insulation
• power transformers
• absorption and resorption currents