▎ 摘　　要

In this work, graphene oxide nanoparticles are dispersed in different concentrations in a soyabean extracted natural ester-based oil-blend having mineral oil as secondary oil and the resulting nanofluids are tested for various dielectric and physio-thermal properties. The results show that with the addition of nanoparticles, the breakdown voltage of nanofluids increases up to 42% as compared to pure mineral oil, 17% as compared to pure ester oil and 15% as compared to the base oil-blend. Relative permittivity and dissipation factor parameters follow a similar trend as well. Thus, the prepared nanofluids can be used as alternative insulating oils in place of the conventional mineral oil in oil-filled transformers.