Enhancement of AC Breakdown Voltage of Magneto Nanofluids Incorporating Co₃O₄ Nanoparticles

Nanofluids have been adopted by power utilities to improve the dielectric capability of transformer oils. The demand for more compact power transformers has driven the need for insulating fluids with enhanced dielectric properties. This study examines the dielectric property of advanced magnetic nanofluids, formulated with synthetic ester oil and mineral oil, under various electric stress conditions. The Cobalt (II, III) oxide (Co3O4) nanoparticles were chosen due to the novelty of the Co3O4 nanomaterial and its better performance. Nanofluids were prepared using a two-step process, with concentrations of 0.005 wt.%, 0.010 wt.%, and 0.020 wt.% in base oil. The determination of breakdown voltage (BDV) was performed using a Verband Deutscher Elektrotechniker (VDE) and spherical-spherical (S-S) electrode system following the IEC 60156 standards. The maximum breakdown voltage is obtained at a particular concentration of nanoparticles for sphere and VDE electrodes. The 12 repetitions were carried out for each set of nanofluid, with BDV measurements noted. The results revealed a significant improvement in the BDV of the nanofluids. Each nanofluid demonstrated maximum % AC BDV enhancement at specific nanoparticle concentrations. The results indicate that the S-S electrode arrangement led to the highest overall improvement for Co3O4 in mineral oil, achieving a 16.10% enhancement, and for VDE electrode configuration led to the highest overall improvement for Co3O4 in synthetic ester oil, with an 18.76% enhancement.