An Approach for Aging State Estimation of Epoxy-Alumina Nano-Composites based High Voltage Dry-Type Insulation using Debye Model Parameters

Epoxy-based insulating material is one of the popular insulating materials for dry-type transformers as well as rotating electrical machines used in high-voltage applications. Due to continuous effect of electrical and thermal stress, this material is aged, and over the years which may lead to premature failure or permanent breakdown of the insulation. Therefore, it is important to understand the aging status, so that the chances of catastrophic breakdown and economic loss can be minimized. This paper is aimed to report this issue on aging effect. To estimate the effect of aging, the polarization and depolarization current (PDC) of the insulating material has been measured. The Debye Model (DM) parameters have been estimated from the depolarization current. The DM parameters can be used as the aging-sensitive marker. Based on that, two empirical equations have been proposed through which the aging state of an epoxy based insulation can be estimated.