The Influence of Organic Functional Molecule Grafting on Space Charge and Electrical Conductivity Behavior of EPDM Insulation

To investigate the influence of grafting modification with 2-allyl-4,6-dibenzoyl resorcinol (ADR) on space charge behavior and conductivity of EPDM insulation, ADR was grafted onto EPDM via melt blending and thermal cross-linking. Systematic analysis examined the effects of varying ADR content on EPDM's chemical composition. Experimental results demonstrate that ADR grafting significantly reduces volume conductivity and suppresses space charge accumulation. Fourier transform infrared spectroscopy (FTIR) confirmed successful covalent bonding of ADR molecules to EPDM macromolecular chains. Space charge characterization and trap distribution analysis reveal that ADR introduces deep traps, effectively inhibiting charge migration and injection. Furthermore, finite element simulations of electric field and charge distributions at HVDC cable joint interfaces show that ADR modification substantially decreases interfacial charge accumulation and reduces electric field modulus disparity between adjacent insulators. This study presents a novel strategy for regulating space charge dynamics and conductivity in HVDC cable accessories through organic functional molecule grafting.