Milestones:Gotland High Voltage Direct Current Link

Date Dedicated
Dedication #
Gotland, Sweden
IEEE Regions
IEEE sections
Achievement date range


Gotland High Voltage Direct Current Link, 1954


The Gotland HVDC Link was the world’s first commercial HVDC transmission link using the first submarine HVDC cable. It connected the Island of Gotland to mainland Sweden. The 96 km-long cable used mass-impregnated technology. The Swedish manufacturer ASEA produced the link for Vattenfall, the state-owned utility. The project used mercury-arc valves for the 20 MW/100 kV HVDC converters, developed by an ASEA-Vattenfall team led by Dr. Uno Lamm.

Street address(es) and GPS coordinates of the Milestone Plaque Sites

57.587716, 18.194615 N 57.587716 E 18.194615

Details of the physical location of the plaque

The plaque will be mounted on a plinth outside the fence of the converter station.

How the intended plaque site is protected/secured

The plaque will be visible from the public street outside the converter station.

Historical significance of the work

The world’s first commercial High Voltage Direct Current (HVDC) transmission link in operation was the Gotland HVDC Link, commissioned in 1954. The Gotland HVDC was installed between the Swedish mainland and the island Gotland in the Baltic Sea. It was the Swedish State Power Board (Vattenfall, the state owned utility) that decided to connect the island’s transmission system to the main transmission system in Sweden with HVDC, and placed the order to ASEA in 1950. The rating for the Gotland HVDC link was set to 20 MW, 200 A, and 100 kV. The project scope in the contract included both the HVDC converters on the mainland and the island as well as the 96 km submarine HVDC cable. The cable utilized mass‐impregnated (MI) technology, and was the worlds’ first submarine HVDC cable. The Gotland HVDC Link capacity was increased in 1970, when power semiconductor technology was introduced in the form of thyristor valves connected in series with the existing mercury‐arc valves, raising the voltage to 150 kV. 1983 a new thyristor valve was installed as a monopole, extended to a bipole in 1987 giving the Gotland HVDC link a capacity of 260 MW at +/‐ 150 kV.

Features that set this work apart from similar achievements

The Gotland HVDC Link with the mercury‐arc valves and HVDC submarine cable commissioned in 1954 stands for a clear milestone in the development of modern and reliable electrical transmission technology. The project comprised several of “the world’s first”, and was the breakthrough in both cable and converter technologies that paved the ground for a number of well‐known large transmission projects using the mercury‐arc valves. Examples of projects include; between England – France (the English Channel), between Denmark – Sweden (Konti‐Skan), in New Zealand (Cross Sound), in the USA (the Pacific Intertie), in Japan (Sakuma), and in Canada (Nelson River).

Significant references

D. Tiku, “dc power transmission – mercury-arc to thyristor HVdc valves”, IEEE Power & Energy Magazine, march/april 2014, pp 76-96: “Subsequently in 1954, the first commercial HVdc submarine Gotland link (20 MW, 100 kV) was commissioned by ASEA” W. Long and S. Nilsson, “HVDC Transmission: Yesterday and Today”, IEEE Power & Energy Magazine, march/april 2007, pp 22-31: “The first commercial order for an HVDC system was given to ASEA by Vattenfall for a 20-MW, 100-kV undersea cable between the Swedish mainland and the island of Gotland in 1950.” “The Gotland HVDC link was commissioned in March of 1954.” O. Peake, “The history of high voltage direct current transmission”, Australian Journal of Multi-disciplinary Engineering, Vol 8, No 1, 2010, pp 47-55: “The Gotland scheme, generally considered to be the first truly commercial scheme in the world, also became the test site for a series of new technology breakthroughs in the development of HVDC. This site is therefore the most significant heritage site in the development of HVDC for several reasons.” F. Nozari and H. S. Patel, “Power Electronics in Electric Utilities: HVDC Power Transmission Systems”, IEEE Proceedings, Vol 76, No 4, April 1988, pp 495-506: “The first commercial dc installation, which remains in operation today, was the Gotland transmission system in Sweden, commissioned in 1954” Bahrman Bjorklund, “The New Black Start – System Restoration with Help from Voltage-Sourced converters”, IEEE Power & Energy Magazine, January/February 2014, pp 44-53: “The very first commercial high-voltage dc (HVdc) transmission system, commissioned in 1954, had blackstart capability. This system links the island of Gotland in the Baltic Sea with the Swedish mainland.”

Supporting materials


Media:Ref2 Long Nilsson 2007 IEEE PE Magazine.pdf





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