High thermal conductivity transformer oil filled with BN nanoparticles

Liquid insulation plays a significant role in the design and operation of power system. There is good evidence in the literature that the addition of nanoparticles to conventional transformer oils can lead to significant increases both in electrical and thermal characteristics. In this paper, spherical BN nanoparticles with high thermal conductivity were added into transformer oil to form nanofluids, with the aim of enhancing electrical and thermal properties. Electrical properties and thermal characteristics of oil samples before and after modification were measured. It was found that the nanofluids have higher AC breakdown voltage and relative permittivity, lower dissipation factor which indicates better electrical properties compared with pure oil. In order to investigate the effect of BN nanoparticles on thermal properties, temperature changes and heat distribution of the nanofluids with different concentrations of BN particles in thermal conductivity process were measured by an infrared thermal imager and a temperature sensor. Obtained results showed that, under the same experimental condition, the heat dissipation of nanofluids with higher concentration of BN particles was faster. It is concluded that the added BN fillers have a very significant effect on electrical and thermal properties in transformer oil-based fluids.