World’s first commercial HVDC link (Gotland 1), a single‑circuit 100 kV, 20 MW mass‑impregnated submarine cable about 96–98 km long between Västervik and Ygne, supplied by ASEA for Vattenfall together with the HVDC converters at both ends.
ASEA was contracted by the Swedish State Power Board (later Vattenfall) around 1950 to deliver the world’s first commercial HVDC transmission link between Västervik on the Swedish mainland and Ygne on Gotland. The turnkey scope covered development of the HVDC technology, engineering and manufacture of the converter equipment at both terminals, and the design, production, testing, laying and installation of a single‑circuit mass‑impregnated 100 kV, 20 MW submarine cable system of roughly 98 km route length. This pioneering MI HVDC cable and associated converters enabled Gotland to replace expensive local oil‑fired generation with mainland power and became the reference project for subsequent mercury‑arc HVDC schemes worldwide.