Assessment of passivated mineral oil in mitigating the formation of copper sulphide in transformers

This study was taken up to understand the variations in concentrations of metal passivators like Irgamet 39 and BTA which are added to mitigate the effects of corrosive sulphur in mineral oil. The study has shown that both BTA and Irgamet 39 are effective in arresting the formation of copper sulphide on conductors. The effect of thermal ageing of oil in presence of reactive species like MBT and DBDS on the concentrations of passivators has been studied and discussed in this paper.