Effect of antioxidants and metal deactivator on the oxidation of transformer oil

Comparative experimental data on the effectiveness of selected antioxidants and a metal deactivator in inhibiting the accelerated oxidation of reclaimed transformer oil are generated using the bomb oxidation apparatus. Energy of activation involved in the oxidation of uninhibited and inhibited oils deduced from the analysis of data are reported. Estimated lives of uninhibited and inhibited oils at the operating temperatures of transformers are also reported. Due to the difference in activation energies of inhibited oils, comparative assessment of inhibitors at a single temperature in the bomb oxidation apparatus as per standard appears to be insufficient. Among the range of antioxidants, i.e. monomeric and polymeric phenolic and aminic antioxidants chosen for study, the grading of only monomeric phenolic antioxidants seems to be consistent with temperature