Universality Evaluation of Polar Melting‐Grafted Polypropylene for Recyclable Power Cable Insulation

ABSTRACT Amid the global “double‐carbon” initiative, melting‐grafted polypropylene (PP) insulation presents a promising technical route for next‐generation power cable systems due to its recyclability, satisfactory dielectric performance, and engineering practicality. However, its universality across both high‐voltage alternating current (HVAC) and direct current (HVDC) systems remains to be fully assessed. In this study, we selected a mature polar grafted PP system: glycidyl methacrylate (GMA)‐grafted PP, to experimentally evaluate its performance and elucidate the underlying physical mechanisms. The results demonstrate that GMA‐grafted PP exhibits excellent DC dielectric performance, including a 24.6% enhancement in breakdown strength and significantly improved space charge distribution, whereas its performance under AC conditions remains unsatisfactory. The GMA‐induced trapping‐detrapping process is proved a key factor contributing to DC improvements, while the study also highlights that polymeric degradation during the melting grafting process, as well as the high polarity of GMA, are responsible for the unfavorable AC performance. In conclusion, 5% (weight percent) GMA‐grafted PP is highly suitable for HVDC cable insulation, but the degradation associated with the melting grafting process is a crucial and urgent issue to be addressed, for the development and universality of high‐capacity recyclable cable systems.