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ABB 20-035, Sitesing, Konti-Skan, Aalborg, Danmark


The first interconnection between Sweden and the western grid in Denmark was established in 1965 with the
250 MW 250 kV KontiSkan 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 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 KontiSkan HVDC project have been a testing ground for new Hitachi Energy HVDC developments:

Pole 1:

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.

Pole 2:

1991: The world's first active DC filter in Lindome.

1993: The world's first electronically controlled AC filter, ConTune, in Lindome.

2019: Hitachi Energy once again returned to this link to perform an upgrade of the control and protection system for the KontiSkan high-voltage direct current (HVDC) transmission link with its latest Hitachi Energy Modular Advanced Control for HVDC (MACH™) technology.

Illustrated overview for KontiSkan
Illustrated overview for KontiSkan
Main Data
Comissioning year: Upgrade: 2019
Pole 2: 1988
Pole 1: 1965
Power Rating: Pole 2: 300MW
Pole 1: 250 MW
No of poles: 2
AC voltage: Pole 2: 400kV (both ends)
Pole 1: 30/150 kV
DC voltage pole 2: Pole 2: 300 kV 
Pole 1: 250 kV
Length of DC submarine cable:

Pole 2: 88 km
Pole 1: 87km
Length of DC overhead line:

Pole 2: 61km
Pole 1: 86 km
Main reason for choosing HVDC:
Length of sea crossing
Application: Interconnecting grids