Study of copper corrosion in transformers due to sulphur in oil using chemical methods

This paper discusses the importance of chemical analysis of transformer oil in understanding the phenomena of copper corrosion in transformers. Parameters like total sulphur, mercaptan sulphur, DBDS concentration and detection of loss of metal passivators due to thermal ageing are discussed with reference to formation and migration of copper sulphide. These evaluations provide useful information about the insulation system which is incomplete when dielectric parameters alone are considered in isolation for understanding the behavior of paper oil insulation.