Presentation Information
[AP2-02-INV]SuperLink: 110 kV HTS Cable for Munich’s Power Supply
*Robert Georg Prinz1, Wescley Tiago Batista de Sousa2, Mathias Noe2, Robert Bach3, Werner Prusseit4, Alexander Alekseev5, Dag Willén6 (1. SWM Services GmbH (Germany), 2. Karlsruhe Institute of Technology (Germany), 3. South Westphalia University (Germany), 4. Theva Dünnschichttechnik GmbH (Germany), 5. Linde AG (Germany), 6. NKT Cables (Germany))
Keywords:
HTS,high voltage cable,SuperLink
As the energy transition advances, inner-city electricity demand increases rapidly due to electric mobility, CO2-neutral heating and cooling, and AI data centers - posing immense challenges for urban distribution network operators. Limited space and high civil-engineering costs make the expansion of conventional 110 kV VPE-cable systems - each providing roughly 100 MVA - very difficult. To relieve urban networks, the “SWM SuperLink” project has for the first time developed a 110 kV high-temperature-superconductor (HTS) cable system with 500 MVA capacity that houses all three phases in a single, flexible cryostat. This design achieves high transmission performance in the city with comparatively little excavation and minimal space requirements.
Funded by the German Federal Ministry for Economic Affairs and Energy (funding indicator 03EN2036), the project objectives were: To engineer a compact, short-circuit-tolerant 110 kV HTS cable system rated at 500 MVA over approximately 15 km. To develop and type-test all necessary components (cable, terminations, splitter box, joint assemblies, cryostat) and install a demo loop. To prove grid integration capability via detailed network calculations and simulations for Munich’s 110 kV system. To demonstrate system longevity and economic viability (capex and opex) compared to conventional solutions. To operate the HTS cable continuously up to full rating for at least six months under real network conditions.
The consortium comprised the network operator Stadtwerke München (SWM), HTS-wire producer THEVA, cable developer and manufacturer NKT Cables, cooling-system specialist Linde AG, and the universities South Westphalia University (FHSWF) and Karlsruhe Institute of Technology (KIT). KIT’s network simulations showed that integrating a SuperLink cable relieves existing 110 kV routes without excessively increasing fault-current levels at substations. A transient thermal analysis confirmed that the SuperLink cable remains superconducting under fault currents and sustains stable operation without significant resistance rise. Material tests at FHSWF demonstrated that the cryogenic high-voltage insulation using “Cryoflex” tape achieves an exceptional breakdown strength of over 165 kV/mm, ensuring high electrical strength and strong partial-discharge resistance. THEVA optimized its production of GdBa2Cu3O7 tapes—especially laser cutting and lamination—so that a 3 mm-wide tape over 200 m continuous length carries 163 A at 77 K. Linde’s thermal–hydraulic simulations with NKT cable parameters showed that the full 15 km route can be cooled with just one intermediate refrigeration station, predicting a cooling power of 30 kW/km. NKT’s short-circuit-tolerant cable design meets SWM’s requirement of sustaining 40 kA for one second. An innovative use of radial core contraction fully compensates the 0.3 % thermal length shrinkage.After type-qualification at DTU Copenhagen, a 150 m test loop was installed in SWM’s Menzing substation in 2024. Figure 2 shows the field layout.
Installation tests, high-voltage qualification, and DC/AC overload tests were completed, leading to the official commissioning of the test loop on 9 October 2024. Long-term operation ran until 1 July 2025, impressively demonstrating the HTS cable system’s performance. Under various load scenarios and weather conditions, the cable system sustained continuous operation at its full 500 MVA rating, reliably conducting the specified 2 625 A in each of the three phases.
Presentation Materials
https://iss-archives.jp/iss2025.jp/slides/AP2-02-INV.pdf
Funded by the German Federal Ministry for Economic Affairs and Energy (funding indicator 03EN2036), the project objectives were: To engineer a compact, short-circuit-tolerant 110 kV HTS cable system rated at 500 MVA over approximately 15 km. To develop and type-test all necessary components (cable, terminations, splitter box, joint assemblies, cryostat) and install a demo loop. To prove grid integration capability via detailed network calculations and simulations for Munich’s 110 kV system. To demonstrate system longevity and economic viability (capex and opex) compared to conventional solutions. To operate the HTS cable continuously up to full rating for at least six months under real network conditions.
The consortium comprised the network operator Stadtwerke München (SWM), HTS-wire producer THEVA, cable developer and manufacturer NKT Cables, cooling-system specialist Linde AG, and the universities South Westphalia University (FHSWF) and Karlsruhe Institute of Technology (KIT). KIT’s network simulations showed that integrating a SuperLink cable relieves existing 110 kV routes without excessively increasing fault-current levels at substations. A transient thermal analysis confirmed that the SuperLink cable remains superconducting under fault currents and sustains stable operation without significant resistance rise. Material tests at FHSWF demonstrated that the cryogenic high-voltage insulation using “Cryoflex” tape achieves an exceptional breakdown strength of over 165 kV/mm, ensuring high electrical strength and strong partial-discharge resistance. THEVA optimized its production of GdBa2Cu3O7 tapes—especially laser cutting and lamination—so that a 3 mm-wide tape over 200 m continuous length carries 163 A at 77 K. Linde’s thermal–hydraulic simulations with NKT cable parameters showed that the full 15 km route can be cooled with just one intermediate refrigeration station, predicting a cooling power of 30 kW/km. NKT’s short-circuit-tolerant cable design meets SWM’s requirement of sustaining 40 kA for one second. An innovative use of radial core contraction fully compensates the 0.3 % thermal length shrinkage.After type-qualification at DTU Copenhagen, a 150 m test loop was installed in SWM’s Menzing substation in 2024. Figure 2 shows the field layout.
Installation tests, high-voltage qualification, and DC/AC overload tests were completed, leading to the official commissioning of the test loop on 9 October 2024. Long-term operation ran until 1 July 2025, impressively demonstrating the HTS cable system’s performance. Under various load scenarios and weather conditions, the cable system sustained continuous operation at its full 500 MVA rating, reliably conducting the specified 2 625 A in each of the three phases.
Presentation Materials
https://iss-archives.jp/iss2025.jp/slides/AP2-02-INV.pdf