The increased dielectric breakdown voltage of transformer oil-based nanofluids by an external magnetic field

In this study, we have measured the dielectric breakdown voltage of transformer oil-based nanofluids in accordance with IEC 156 standard and have investigated the dielectric breakdown performance with the application of an external magnetic field and different volume concentrations of magnetic nanoparticles. It was confirmed that the dielectric breakdown voltage of pure transformer oil is about 10 kV with a gap distance of 1 mm between electrodes. In the case of our transformer oil-based nanofluids with 0.08% < Φ < 0.39% (Φ means the volume concentration of magnetic nanoparticles in the fluid), the dielectric breakdown voltage was three times higher than that of pure transformer oil. Furthermore, when the external magnetic field was applied under the experimental vessel, the dielectric breakdown voltage of the nanofluids was above 40 kV, which was 30% higher than that without the external magnetic field.

► We measure the dielectric breakdown voltage in magnetic nanofluids experimentally.
► Nanofluids with different volume concentration (Φ) with 0.08% < Φ < 0.39% are prepared.
► The dielectric breakdown voltage is three times higher than that of pure base liquid.
► It also shows remarkable increase in the dielectric breakdown voltage under external magnetic field.
► Further researches on the direction of external magnetic field and the visualization of the magnetic nanoparticles should be conducted.