Electric Field Stress Reduction in High Voltage Cable Joint by Functional Capacitive Field Grading Composites

Traditional electric field grading approaches, such as geometric grading and foil-based capacitive field grading, often result in bulky designs that limit the power density of electrical equipment. In contrast, functional dielectrics, such as functional capacitive field grading composite (FCFGC) materials, offer an effective solution for mitigating high electric fields without compromising power density. In this study, we fabricate, characterize, and apply FCFGC materials to high-voltage AC (HVAC) cable joints operating under power frequency conditions. We experimentally characterize the field-dependent permittivity of the fabricated composites and integrate these properties into multiphysics finite element analysis (FEA) models. The FEA simulations demonstrate a 63% reduction in electric field intensity achieved through the implementation of FCFGC materials, highlighting their potential for enhancing the reliability of HV insulation systems.