Effect of SiC nano-size fillers on the aging resistance of XLPE insulation: A first-principles study

Effective strategies to prevent the electrical tree growth and extend the lifetime of cross-linked polyethylene (XLPE) insulation are of crucial importance for the development of power cable industry. The first-principles study with DFT method was performed to understand the mechanism of aging resistance for SiC/XLPE nanocomposite. The Bader charge redistribution calculations between different types of silicon carbide and XLPE suggest that SiC fillers have the ability of capturing hot electrons to suppress the accumulation of space charges because of their unsaturated electronic structures and magnetism on the Si- or C-terminated surfaces. The interfacial behavior between SiC and XLPE was investigated based on the physical interaction and chemical reactivity. The 3C, 4H and 6H-type SiC with flat Si-terminated surfaces are proposed to be favorable additives by showing relatively strong physical interaction with XLPE to limit its movement, and high activation energy for the hydrogen migration reaction to protect the XLPE.