Synthetic Ester Oil Based High Permittivity CaCu3Ti4O12 (CCTO) Nanofluids an Alternative Insulating Medium for Power Transformer

Green insulating oils are the present industry need for an alternative insulation to mineral oil due to its higher bio-degradability. Synthetic ester oil plays a prominent role by compromising all the critical parameters for better adaptability to power transformers. Presently, high dielectric nano-additive based enhancement studies have been targeted for the development of newer insulation with improved dielectric withstand levels. The present work deals with synthetic ester oil based high dielectric permittivity CCTO (CaCu3Ti4O12) nanofluids. The dielectric, physical and chemical properties are examined according to the applicable IEC and ASTM standards. The breakdown voltage enhancements found for AC (41.6%) and lightning impulse (17.3%) has been observed. Also, a decrement in loss tangent and increment in dielectric permittivity has been observed. An increment in volume fraction loading results in an increment in partial discharge inception voltage, thermal conductivity and flash point properties. Hence, based on overall enhancement performance, <0.01% CCTO is considered as the optimum addition to synthetic ester oil which is considered as an alternative medium as well as next generation fluid for power transformers.