Enhancement of Insulation Properties of 500 kV DC Cross-Linked Polyethylene Utilizing Functionally Modified Fullerene with Electron-Induced Effect

Abstract This paper reports the effect of m-aminobenzoic acid-functionalized modified fullerene (fC60) doping on the insulation performance of cross-linked polyethylene (XLPE) composites. By leveraging the electron-induced effect of the fC60 structure, uniform electron capture onto the C60 molecular orbitals is achieved. Kelvin probe microscopy, DC conductivity, DC breakdown, dielectric properties, differential scanning calorimetry, and quantum chemical calculations were performed on the samples to analyze the insulation performance of XLPE before and after modification. The results show that the DC breakdown field strength of the XLPE composite material with fC60 added is 13.76% higher than that of pure XLPE. Moreover, this composite material exhibits lower DC conductivity and dielectric loss, with a slower and smaller rate of surface potential attenuation. The sample’s crystallinity increases as its lamellar thickness decreases. Quantum chemical calculations show that a potential barrier forms at the interface between XLPE and the quantum-well fC60, uniformly dispersing electrons within the fC60 molecular cage and effectively reducing the electric-field distortion at the fC60-XLPE interface.