Partial Discharge Characteristics of Nanofilled Mineral Oil

The oil-paper system forms the predominant insulating material in many of the high voltage transformers. The insulation system of a high voltage transformer should be reliable, efficient and economical. The present focus of insulation material development is on the inclusion of nanoparticles in the transformer liquid dielectric, resulting in nanofluids with improved dielectric properties. The present work involves the development of nanofluids, its stability assessment and analysis of partial discharge characteristics. Insulating alumina nanoparticles of 0.1wt% and 0.03wt% are added to mineral oil, with and without a surfactant Oleic acid. The effect of Oleic acid modified nanoparticles on the stability and dielectric properties of nanofluids are also discussed. Nanofluid with 0.03wt% nanoparticle and 0.1wt% Oleic acid show favourable stability, improved partial discharge and a higher breakdown strength.