Performance Evaluation of Nano-fluids Based Mineral Oils for Application in Power Transformers

Power transformers are the core of transmission and distribution of electric power in power systems. Nanofluids are introduced to optimise the properties of insulating oil. Mineral-oil based nanofluid are prepared by dispersing 0.02 wt% concentration of nanoparticles into the pure oil. In this paper, the thermo-physical properties such as thermal conductivity and viscosity of pure mineral oil (MO) and nanofluid are evaluated for different temperatures starting from room temperature up to 55 °C at a gap of 10°C. Two different types of nanoparticles (i.e. Al
₂
O
₃
and TiO
₂
) are dispersed in the mineral oil by means of two-step process. The experimental for thermal conductivity is performed using TC-4 equipment that follows the concept of heat conduction in liquids, and the relative viscosity is determined using a redwood viscometer, as per the procedure outlined in ASTM-D445 experimental standard. The experimental results show that the nanoparticles have a positive influence on thermophysical properties of oils, but the temperature negatively affects them. Also, the Al
₂
O
₃
nanofluid exhibits better thermal conductivity than TiO
₂
nanofluid and pure mineral oil for the complete range of temperature.