Thermal aging effect on the properties of new and reclaimed transformer oil

The main of this study is to investigate the accelerated thermal ageing effect on three kinds of oil namely new mineral oil, reclaimed used oil and re-reclaimed aged oil. The oil degradation is mainly caused by temperature. The temperature increase reduces the time life of transformer oil. In order to obtain the same quality of new transformer oil, the reclamation process is based on the regeneration (by fuller's earth) of the main service transformer oil properties. This is done in presence of copper and paper. Thus, new mineral oil, reclaimed used oil and re-reclaimed aged oil are kept under 100 degrees C in different ageing times. The physicochemical and electrical analysis of the different properties of oil depending on the applied temperature, are measured according to specifics standards. The tests results reveal the characteristics improvement of reclaimed used oil after regeneration process.