Search

Mineral oil has been serving well as a cooling and insulation oil in high voltage power equipment but with a setback when considering environmental friendliness whenever there is spillage due to its poor carbon profile. Several works have been done on the enhancement of dielectric properties of green alternative with different nanoparticles but little attention was placed on its cooling properties which is one of the major functions of the oil. Also, to prevent food competition, esters from a non-edible seed oil should be given more consideration. This work, therefore, investigates the cooling properties of synthesized insulating nanofluid using Neem oil ester as the base fluid together with (Insulating) SiO 2 and (semiconductive) WO 3 nanoparticles. The nanoparticles were characterized using FTIR and XRD to confirm their functional groups and crystallite size respectively. Transesterification of the oil was done using sodium methoxide and the nanofluid samples were prepared by dispersing the nanoparticles into the oil. The nanoparticles were varied from 0.2 wt% to 1 wt%. The pour point, flash point and viscosity were measured according to ASTM standards. An increase in the pour point, flash point and viscosity were observed at every loading of the nanoparticle. The nanofluid with dispersed SiO 2 nanoparticles were observed to possess superior properties as a cooling liquid in high voltage power equipment when compared with the fluid with WO 3 nanoparticles because of its low viscosity, low pour point and good flash point. After the ageing, the synthesized fluids still retained their properties which is better than the mineral oil. • The influence of SiO 2 and WO 3 nanoparticles on the physical properties of the Neem oil ester was examined. • The two nanoparticles enhance the Flash point of the Neem oil ester. • An increase in the pour point of the Neem oil ester was observed through addition of the two nanoparticles. • A slight increase in the viscosity of Neem oil ester was observed after the addition of the particles. • After ageing of the nanofluids, the viscosity of the nanofluid was found better than the viscosity of the aged mineral oil. [ABSTRACT FROM AUTHOR]

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 Al 2 O 3 and TiO 2 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 Al 2 O 3 and TiO 2 nanoparticles ranging from 0.2 wt% to 1 wt% in a step of two to understand the behaviour 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 1 wt% but with a more noticeable decrease when considering Al 2 O 3 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. Image 1 • Examine the influence of nanoparticles on the properties of ester insulating fluid. • The nanoparticles enhances the physicochemical properties of the fluids. • The nanoparticle dispersion led a decrease in the dielectric loss. • Optimum DC breakdown voltage was observed at 0.6 wt% for Al 2 O 3 and TiO 2 nanofluid. • The study confirmed that Al 2 O 3 nanofluids will serve well as an insulation fluid. [ABSTRACT FROM AUTHOR]