Polymeric materials for high-voltage insulation in power transmission systems: Advances, challenges, and future perspectives

Polymeric materials have been instrumental in present-day high-voltage (HV) electrical systems because of their high dielectric strength, light weight, design flexibility, and cost-effectiveness, which make them the basis for reliable and efficient energy transmission systems. As the incorporation of renewable energy and the construction of long-distance HV direct current (HVDC) power transmission require sophisticated insulating materials that can ensure grid reliability, thermal stability, and long-term stability, demand is high. This is a review of polymeric materials for HV insulating applications, with a particular focus on thermoplastics, thermosetting polymers, and elastomers, and their electrical, thermal, mechanical, and environmental characteristics. Unlike traditional reviews, this paper presents a systematic correlation between polymer type and the evolving performance specifications of next-generation energy transmission systems, such as HVDC cables, substations, and outdoor insulating materials. The most important degradation processes, including electrical aging, partial discharge (PD) activity, ultraviolet (UV) radiation, thermal stress, and environmental contamination, are studied critically. New technologies in nanocomposites, surface modification strategies, additive manufacturing (AM), and recyclable polymer systems are presented as potential solutions to improve insulation life, energy efficiency, and sustainability. Moreover, the review draws attention to issues related to aging over the long term, material recyclability, and life-cycle performance, which continue to be bottlenecks on the path to fully sustainable power grids. The combination of material performance trends with new manufacturing technologies proposed in the present research offers useful insights and future research directions toward the creation of high-performance polymeric insulating materials capable of supporting efficient, reliable, and sustainable electrical energy transfer systems.