Investigations on Dielectric Properties of Nano SiO2-Mineral Oil for Transformer Insulation Applications

Abstract

Successful operation of electric power transmission and distribution network depends on the consistency of power transformers. Any unscheduled outage due to a faulty transformer leads to expensive and time consuming repair work and affects the entire power system reliability. Majority of the power transformer faults occur due to aging and degradation of oil insulation. Mineral oil is being used as a liquid dielectric in transformers for a longer period of time. In general, periodic monitoring of electrical, physical and chemical properties will certainly give information about the aging and deterioration of insulating oil. In recent times, advancements in nanotechnology has given scope for the development of nano-dielectrics for transformer insulation applications. Many research works are being carried out to understand the dielectric performance enhancements in nano-modified insulating oils for high voltage applications. In the present work, dielectric properties of nano-SiO2 modified mineral oil is investigated. Detailed reports on the characteristics of nano SiO2-modified mineral oil such as breakdown strength, loss factor, volume resistivity, viscosity, flash point and fire point are scanty. Hence, this paper attempts to investigate the above mentioned characteristics of SiO2 nanofiller added mineral oil at different %wt concentrations of nanofiller material. Results clearly show that addition of SiO2 nanofiller material in the base mineral oil enhances dielectric performance of mineral oil. These results will be useful for electrical utilities in improving the design aspects, identifying the root cause of insulation failures and carrying out the preventive maintenance activities of transformers.