The first interconnection between Sweden and the western grid in Denmark was established in 1965 with the 250 MW 250 kV Konti-Skan HVDC link across the Kattegatt, a narrow bay in southern Scandinavia, stretching from Gothenburg in Sweden to Aalborg in Denmark. The owners of the link are Energinet.dk and Svenska Kraftnät.
The converter stations were based on mercury-arc valve technology and situated in Stenkullen in Sweden, and Vester Hassing in Denmark. A second Konti-Skan cable rated 300 MW was added in 1988 from Lindome on the Swedish side to Vester Hassing. In 2006, the mercury-arc converters were replaced by thyristor converters.
Both poles of the Konti-Skan HVDC project have been a testing ground for new ABB HVDC developments:
1973: Second generation thyristor test valve, 135 kV, 1,050 A (air cooled) in Vester Hassing.
1988: Light triggered thyristor (LTT) test valve, 135 kV, 1,050 A in Vester Hassing.
1992: The world's first air insulated outdoor thyristor valve, 135 kV, 1,050 A, in Stenkullen.
1991: The world's first active DC filter in Lindome.
1993: The world's first electronically controlled AC filter, ConTune, in Lindome.
In 2017, ABB will once again return to this link to perform an upgrade of the control and protection system for the Konti-Skan high-voltage direct current (HVDC) transmission link with its latest ABB AbilityTM based MACHTM technology.