Study on Multiple Self-Healing Characteristics of Microcapsule/XLPE Composites With Reversible Disulfide Exchange

Cross-linked polyethylene (XLPE) cables are widely used in modern power systems due to their superior electrical insulation performance and mechanical strength. However, electrical and water tree aging damages tend to occur in their insulation layers, which seriously endanger the safe and stable operation of power grids. In addition, existing cable self-healing systems have insufficient multiple self-healing performance. In this paper, reversible disulfide bonds are combined with microcapsules to prepare electrical-water dual-responsive multiple self-healing microcapsules, and the corresponding XLPE composites are further obtained. The results show that the microcapsules are successfully fabricated. The composite with 1.0 wt% microcapsule doping content exhibits optimal comprehensive insulation properties. PDC tests verify its excellent primary and multiple self-healing capabilities. Breakdown field strength tests before and after aging further confirm its favorable self-healing performance. After one electrical tree aging, the breakdown field strength of the composite recovers to 92.6% of the original value, and it still reaches 84.5% after three electrical tree aging cycles. After water tree aging, the breakdown field strength recovers to 91.5%. This microcapsule multiple self-healing system provides a new technical approach for extending the insulation life of XLPE cables. Highlights Microcapsules are employed to self-heal tree aging damage in XLPE insulation. This system simultaneously self-heals electrical and water tree aging damage. This system repeatedly self-heals electrical tree aging damage.