A new type of nano APTES-hBN modified palm oil as natural ester insulating oil with upgraded thermal aging characteristics

Abstract

In this paper, nano hexagonal boron nitride grafted with silane coupling agent (APTES-hBN) is selected to modify the natural ester, conducts thermal aging tests on the modified natural ester insulating oil and explores the mechanism of the nanoparticles on the improvement of natural ester properties from a microscopic perspective combining with molecular dynamics. The experimental results show that the addition of Nano APTES-hBN inhibited the production of acids in oil-paper insulating, leading to a corresponding decrease in the number of polar molecules in the oil. Compared with crude oil, the acid value and dielectric loss factor in the modified oil are reduced by 8.4% and 43.8%, respectively at the end of aging, and the rate of increase is smaller. Through its mechanism study, it is found that the addition of Nano APTES-hBN results in a tighter interfacial bonding between oil and paper insulation, and the adsorption energy of modified natural ester insulating oil to H3O+ is greater. The addition of Nano APTES-hBN introduced a large number of electron traps, providing a medium for the transition of valence electrons. At the same time, there are hydroxyl groups with strong electrostatic potential on Nano APTES-hBN, which have strong adsorption effect on charged particles. In addition, the Nano APTES-hBN is able to form hydrogen bonds with acids, which slows down the promotion of hydrolysis of ester molecules by acids, and thus improves the thermal stability of the modified natural ester insulating oil.