Comparison of Antioxidant Influence on Mineral Oil and Natural Ester Properties under Accelerated Aging Conditions

Increased power densities drive researchers to enhance and improve the life of insulation system employed in transformers. In order to reduce the oxidation process and enhance the life of liquid insulation, Anti-Oxidant (AO) additives are usually added with Liquid Insulation (LI). The main aim of this research work is to understand the behaviour of LIs with AO additives under thermally aged condition. Here, Butylated Hydroxy Toluene (BHT) AO and natural esters like Sunflower oil (SFO) and Rapeseed oil (RSO) are used for analyses and then subjected to an accelerated ageing test. Important life determining properties of inhibited and uninhibited Mineral Oil (MO), SFO and RSO samples are examined and compared. From the experimental results, it is concluded that the degradation rate of inhibited samples are lesser than that of uninhibited samples. Also, inhibited SFO samples show similar or better performance compared to MO and RSO samples.