Enhancement of Surface flashover performance of epoxy by doping POSS nanofillers

Abstract

Surface flashover is key issue to limit the development of high voltage insulation equipment. Various nano-fillers are added to improve the performance of epoxy composites. With the ultimate goal to enhance the surface flashover performance, two different types of polyhedral oligomeric silsesquioxane (POSS) nanometric molecular structure is doped into neat epoxy. Surface flashover voltage has been tested under DC voltage in SF6 gas. Isothermal surface potential decay (SPD) test were conducted to find out the surface charge characteristics. Quantum chemical calculation was performed to investigate the absolute energy value of Lowest Unoccupied Molecular Orbital (LUMO) level for epoxy/POSS composite, associated to electron affinity for charge carriers. Results specifies that flashover voltage has been positively influenced by both trap energy and trap density of charges. While improved flashover performance of EP/OG-POSS composite compared to EP/ECH-POSS and pristine sample is attributed to deep traps for charges. The energy distribution diagram shows that EP/OG-POSS has higher affinity for charge carrier in EP/OG-POSS comparatively. The affinity for carriers assists the charge trapping centers. Moreover, functional properties of POSS side groups can determine the tailoring of deep trap; moreover, the simulated electronic properties are helpful to understand the improved properties of surface flashover voltage.