Positive
Project advancing - milestone achieved
Medium Impact
Significant progress or notable issue
In 1970, the original Gotland 1 HVDC submarine link between Västervik on the Swedish mainland and Ygne on Gotland was uprated, with ASEA and Vattenfall increasing its transmission capacity from 20 MW to 30 MW and raising the DC voltage from 100 kV to 150 kV by installing the first commercial thyristor modules in series with the existing mercury‑arc valves while continuing to use the original mass‑impregnated submarine cable.