Thermal stability of APTES surface modified nano SiO2 insulating oil

Nano-modified insulating oil has excellent electrical properties and wide application prospect in power system. APTES (H2NCH2CH2CH2Si(OC2H5)3), as a common organic surface modifier, can enhance the interaction between nanoparticles and organic matrix and further enhance the properties of nanocomposites. In this paper, the effect of APTES surface modification on the thermal aging characteristics of nano-SiO2 modified insulating oil was studied by thermal aging experiment and molecular dynamics simulation. The results of thermal aging test show that the nano-SiO2 modified insulating oil with APTES surface modification has better dispersion stability, and the acid value and dielectric dissipation factor are reduced by 22.22% and 36.18% respectively. The mechanism analysis results show that the modification of nano-particles can limit the diffusion of formic acid to cellulose, protect the internal hydrogen bond structure, effectively slow down the aging process of oil-paper insulation system, and make it have better thermal stability.