Experimental validation of thermal model of unfilled and nano filled transformer oils

The thermal properties of a transformer insulating oil determines the loading capacity and working life of a transformer. Nanotechnology implementation in liquid dielectrics has resulted in nanofluids with improved thermal and electrical properties. The paper details upon an electro-thermal analogous model to find the thermal resistance and thermal capacitance of unfilled and Aluminum Nitride nanoparticle filled transformer oil at different particle concentration. The simulation of the thermal model for unfilled and filled insulating fluids has been done using Comsol Multiphysics and the results have been validated experimentally. Both the simulation and experimental results show a considerable reduction in the thermal resistance and thermal capacitance of the filled transformer oil. An optimal nanoparticle concentration of 0.20 percentage by weight provides the desired thermal characteristics without compromising on the stability of the nanofluid. The results indicate improved thermal properties and hence longer transformer life for nanocomposite filled transformer oil than the unfilled transformer oil.