Abstract
Epoxy resins are widely used to build insulators in GIL. Epoxy/AlN nanocomposite can be produced by adding AlN nanoparticals to the epoxy resin. By studying the surface discharge behavior of the nanocomposites under different operating temperature, it is helpful to improve the creeping voltage of epoxy resin. Polypropylene is a kind of material which is usually chosen to build film capacitors. The effects of voltage form on surface charge and discharge behavior were studied. Furthermore, a modification method of a polypropylene film which can suppress surface charge accumulation is proposed. Polypropylene also has great application potential in HVDC cable insulation, provided that its toughness is to be overcome. Different mass fractions of ULDPE and graphene were added to polypropylen to improve mechanical and insulating properties, respectively. Studies on the DC conductivity, space charge behavior, trap level distribution, and breakdown strength of the new material were carried out.