Accelerated Thermal Aging Effect on The New and Reclamation Transformer Oil Behavior

This paper is devoted to an accurate investigation on the various dielectric and physicochemical properties of two kinds of transformer oils, which are submitted to accelerated thermal aging in presence of copper and presspahn. The first one is a non-treated new oil while the second one namely reclaimed oil, is extracted from transformer commissioned in 1989. The used oil is reclaimed in laboratory by adsorption process, in order to restore its quality by removing contaminants and restoring its insulating properties. The two kinds of oils are submitted to accelerated thermal aging under two temperatures 100°C and 120°C, in order to assess the stability of both oils. The investigated parameters are dissipation factor, acidity, hydrogen gas, viscosity, resistivity and index color, according to specifics standards. It’s shown that reclaimed oil degrades more quickly during thermal aging than new oil in presence of copper and presspahn. The results reveal instability of reclaimed used oil after accelerated thermal aging process.