LAUSR

Abstract A clean alternative insulating oil has been the quest of researches over the years due to non-degradability of mineral oil and safety issues. With the application of nanoscience and nanotechnology, the potential of transformer oil-based nanofluids has been thoroughly investigated with signs of significant improvement. Attention was placed on natural ester as a green alternative and it was realized that it has the potential to become a replacement for mineral oil. However, for natural ester-based nanofluids, the performance analysis is not well explored and there is still room for more investigations. This paper focused on the improvement of the physicochemical properties, dielectric loss and breakdown voltage of palm kernel oil ester using Al2O3 and TiO2 nanoparticles. The nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX). The physicochemical properties, relative permittivity, dielectric loss, and high voltage DC conductivity of the nanofluid samples were studied with varying weight percentages of Al2O3 and TiO2 nanoparticles ranging from 0.2 wt% to 1 wt% in a step of two to understand the behavior of the materials. The adequacy of the fluid samples as an electrical insulating fluid in oil-filled high voltage (HV) electric equipment was explored and compared. For both types of nanoparticles, the dielectric loss was observed to decrease at 1wt% but with a more noticeable decrease when considering Al2O3 nanoparticle. Measurement of DC electrical breakdown voltage of the ester-based nanofluids revealed that the dispersion of nanoparticles in the fluid result in an increase in the breakdown voltage of the base fluid with the optimum value obtained at 0.6 wt%. The study indicated a decrease in the dielectric loss of the nanofluid sample and exhibited improved breakdown voltage when compared with the base alkyl ester.