A Review on Insulation and Dielectrics for High- Temperature Superconducting Cables for Power Distribution: Progress, Challenges, and Prospects

The high-temperature superconducting (HTS) ac and dc cables are gradually finding their way toward commercialization due to their ability to transfer bulk electric power with negligible dielectric loss. In this context, this article critically reviews the different aspects of HTS cables used in various applications and related accessories. The operational, laboratory-scale, and prototype HTS cable projects are discussed in detail. Different dielectrics, electrical insulations, superconductors, cooling systems, cryogens, and upcoming projects of HTS cables are reviewed. The underlying challenges and future directions in ac and dc cables, electric aircraft and ships, associated costs, cryogenic insulation materials, cooling technologies, superconductors, and electrical insulations of HTS cables are discussed in detail. The space charge performance of presently used polypropylene laminated paper insulation and future insulation, i.e., Kapton material, is experimentally analyzed, to show the future challenges in the insulation design. The technology readiness level, market trends, and relevant test standards are explored. The research and market trends suggest that HTS cables can replace conventional transmission methods. However, their consistent growth and adaptation of HTS cables will depend on the design of cryocoolers, raw material cost of superconductors, and large-scale production.