Additive Interaction Effect on High-Temperature Stability of XLPE Insulation for High-Voltage Cables

The high-voltage cable is one of the key equipment for power transmission, and its reliable operation depends on the crosslinked polyethylene (XLPE) insulation. The XLPE insulation not only requires excellent dielectric performance but also remarkable high-temperature stabilities, including the antiscorching characteristic during the extrusion process evaluated by the torque curves, antioxidation properties measured by oxidation induction time (OIT) and the thermal elongation determined by the hot set method. In general, the high-temperature stabilities are significantly influenced by the additives. This paper proposes and substantiates the concept of regulating the high-temperature stabilities of XLPE insulation by the synergistic effects of antioxidants and crosslinking agents. Specifically, the positive effect of antioxidants on the antiscorching characteristic, thermal elongation and OIT of XLPE insulation is related with the dicumyl peroxide content. This study illustrates the intricate correlation between the high-temperature stabilities of XLPE insulation and the additives, thereby offering valuable guidance for the formulation design of XLPE insulation for better performance.