Study on the Enhancement of Interaction between Surface Groups Modified Nanoparticles and Natural Ester Insulating Oil

Abstract

Power transformers in high-voltage power grids are among the most critical components, and insulating oil serves as the most important liquid dielectric medium inside high-voltage power transformers, playing key roles in insulation, heat dissipation, and monitoring transformer operating conditions. In recent years, considering environmental protection and the application of nanotechnology, researchers have explored the use of nanomodified natural ester insulating oil as a substitute for traditional mineral insulating oil. However, the interfacial compatibility between nanoparticles and insulating oil has not yet been properly addressed. In this work, natural ester insulating oils modified with SiO₂ nanoparticles functionalized with four different groups were prepared, and their key physicochemical properties were tested. Meanwhile, molecular dynamics simulations were employed to investigate the surface interactions between triglycerides and the nanoparticles. The results indicate that SiO₂ nanoparticles modified with functional groups all enhance the thermal conductivity of the insulating oil, with the APTES-SiO₂ exhibiting the most pronounced effect. The molecular simulation results suggest that functionalized nanoparticles improve compatibility with the insulating oil, inhibit the generation and development of streamers within the oil, and thereby prevent macroscopic breakdown of the insulating oil. This work can provide a solid theoretical foundation for the application of nanotechnology in liquid dielectric media.