Synergistic effect of electric field and temperature on POSS modified natural ester insulating oil: A molecular dynamics study

Abstract

The use of nano-materials can effectively improve the dielectric and heat transfer properties of natural ester insulating oil. However, the migration and interaction mechanism of components in nano-modified insulating oil under electric field is still not clear. Through detailed Molecular Dynamics (MD) simulation, this study revealed the migration and interaction mechanism of Cage Polysilsesquioxane (POSS) and H2O molecules in natural ester insulating oil. The data indicates that POSS and H2O molecules have completely different diffusion properties under electric field. The existence of electric field not only makes the displacement of molecules nonlinear, but also limits the Brownian motion of H2O molecules. On the contrary, POSS molecules under electric field have better diffusion properties. Electric field leads to the extremely uneven distribution of electrostatic potential (ESP) of oil molecules, which makes it easier for H2O molecules with small volume to dissociate near the polarized oil molecular structure and be bound by it, and the interaction energy between oil molecules and POSS molecules under the action of electric field will be weakened, which is the main reason why H2O and POSS molecules have completely different diffusion performance under electric field. The limited displacement of H2O molecules can inhibit the aging of insulating oil and improve its service life. Compared with the electric field effect, temperature has a great influence on the interaction energy between POSS and oil molecules. The results provide useful guidance for the design of the next generation of natural ester nano-modified insulating oil.