Epoxy resins are popular insulating materials in the electrical industry. Resin-insulated transformers have been widely used for several decades to address the need to limit the risk of fire and environmental contamination and for ease of installation. In addition, for the same power output, resin transformers not only have smaller footprints but also do not require any kind of periodic maintenance. Resin is subject to various degradation phenomena that eventually compromise the properties of the material, causing the transformer to fail.

Some authors in the literature have investigated the degradation aspects of resins, proposing several solutions for the creation of silicone-reinforced resins for greater resistance to aging. At present, however, there are no accurate methods, technologies or techniques for nondestructive field evaluation and detection of the effects of material degradation or aging, nor are there accurate monitoring techniques for failure prevention. This report outlines the research aimed at improving the diagnostics of resin-insulated transformers. The activities were developed from a literature review of the diagnostic methodologies on the market and required by law.

Concurrently, chemical and physical models of a resin-insulated transformer are being developed. In addition, an automated test set-up was created for the automatic execution of thermal aging cycles. These tests, together with the theoretical part, will be the starting point for the development of a sensor to be integrated into the transformer for predictive diagnostics. An attempt will also be made to identify how electrical and thermal stresses can change the structure of the resin thus causing the degradation of its dielectric properties.