The HVDC, Gotland, Sweden is the oldest plant for high voltage direct current transmission in the world. The first HVDC Gotland service (Gotland 1) went into service in 1954. It could transfer 20 megawatts over a 98 kilometer long submarine cable between Vaestervik and Yigne to Gotland with a voltage of 100kV. As a static inverter, mercury vapour electric rectifiervalves are used.

In 1970 the service was re-engineered to transmission capacity of 30 megawatts at a voltage of 150kV by using the first thyristor module for HVDC applications.

However even this capacity was not high enough and in 1983 a new link, HVDC Gotland 2 (transmission capacity: 130MW, transmission voltage: 150kV, cable length of 100 kilometers) and then HVDC Gotland 3 (transmission capacity: 130MW, transmission voltage: 150kV, cable length of 103 kilometers) were built. The latter made the HVDC Gotland 1 redundant and led to its deactivation and disassembly.

• http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/gad/gad02181.nsf&v=17EA&e=us&m=100A&c=C1256D71001E0037C1256A140042E2D3
• http://www.transmission.bpa.gov/cigresc14/Compendium/GOTLAND.htm
• http://www.transmission.bpa.gov/cigresc14/Compendium/Gotland%20Pictures.pdf