Reliable Assessment of Oil-Paper Insulation Used in Power Transformer Using Concise Dielectric Response Measurement
D. Mishra, Arijit Baral, S. Chakravorti
Abstract
Oil-impregnated paper is usually the preferred choice of insulation in power transformers. The working life of any transformer depends on its insulation condition. The paper conductivity, moisture content, and dissipation factor of solid insulation are a few crucial parameters used to determine the insulation condition. The reliable estimation of such parameters for the diagnosis of solid insulation requires a complete profile of polarization current, which is time-consuming. Hence, utilities always prefer noninvasive and rapid techniques to predict insulation conditions and minimize shutdown time. The proposed technique is based on short-duration polarization current data. The present manuscript suggested a method that uses the initial decay rate (IDR) of recorded polarization current data to predict various performance parameters related to paper insulation. In order to show the effectiveness of the proposed method, the analysis is performed on the data measured from various in situ transformers.