Self-Healing Solid Insulating Materials for High-Voltage Applications: Mechanisms, Performance, and Future Directions

Self-healing materials feature a self-directed process to heal micro-damage, ensuring the recovery of mechanical strength and dielectric properties in the absence of external intervention. Self-healing insulation materials are an exciting development for enhancing the longevity of high-voltage (HV) electrical devices in stringent operating environments. This review provides a systematic approach to studying different self-healing strategies for HV insulation systems. This includes both extrinsic and intrinsic approaches. In this regard, the review critically examines the SMASH strategy, covalent adaptable network, magnetothermal healing, electroluminescent triggered repair, and artificial intelligence based diagnostics system in detail. The main damage modes of electrical devices (namely, electrical treeing, water treeing, partial discharge erosion, and space charge accumulation) and the characterization techniques needed to quantify healing performance. This review focuses on HVDC cable insulation, transformer dielectrics, wide bandgap semiconductor packaging, and offshore/sub-sea equipment in a systematic manner. The review also addresses the role of artificial intelligence in discovering new materials, predictive maintenance, and fault management in grids. Finally, the paper highlights eco-friendly molecular design, lifecycle sustainability, extreme-environment performance, industrial feasibility, and healing efficiency.