HVDC Gotland
Encyclopedia
The HVDC Gotland, on the Swedish
east coast, was the first fully commercial static plant for high voltage direct current transmission in the world. The first HVDC Gotland link (Gotland 1) went into service in 1954. It could transfer 20 megawatts over a 98-kilometer-long submarine cable between Västervik
on the mainland and Ygne on the island of Gotland
, with a voltage of 100kV. As a static inverter
, Mercury arc valve
s were 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 monopolar link, HVDC Gotland 2 with a transmission capacity of 130MW and a transmission voltage of 150kV was estalished. It consists of a 92.9 kilometers long cable with a single copper conductor of 800 mm2 cross section, from which 92 kilometres are submarine and 0.9 kilometres underground. Beside this, HVDC Gotland 2 has a 6.6 kilometres long overhead powerline section between Västervik static inverter plant and the Swedish Coast. It has 2 Aluminium conductors each with a cross section of 910 mm2, which are installed on wooden poles - perhaps the only HVDC powerline using such poles. In 1987 HVDC Gotland 3, a further monopolar link, with a transmission capacity of 130MW and transmission voltage of 150kV was installed. It consists of a 98 kilometers long cable with a single copper conductor of 800 mm2 cross section. 92 kilometres of this cable are laid in the sea and 6 kilometres underground on land.
The grounding electrode of the Västervik Inverter Station is situated at Almvik on Östra Eknö, that of Ygne Inverter Station at Gravfält. Both electrodes are used for Gotland 2 and Gotland 3 and are situated in sea-water filled basins close to the sea. At Almvik there are 2 such bassins, while Gravfällt uses only one. The basin design of the electrodes prevents fishes from getting too close to the electrodes, which may harm them.
Almvik electrode is connected with Västervik Inverter Station by an 18.95 kilometres long line with 4 overhead line and 3 submarine cable sections for strait crossings. The overhead line sections, which have a total length of 17 kilometres are installed on wooden poles and consist of 2 Aluminium conductors each with 910 mm2 cross section. The total length of the cable sections amounts to 1.95 kilometres and consist of 2 cables each with 1000 mm2 cross section. The connection between Ygne Inverter Station and Gravfält Electrode has a length of 12.75 kilometres. It consists of a 12 kilometres long overhead line on wooden poles, which uses 2 Aluminium conductors each with 910 mm2 cross section and a 0.75 kilometres long underground cable consisting of 2 Aluminium conductors each with 1000 mm2 cross section.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
east coast, was the first fully commercial static plant for high voltage direct current transmission in the world. The first HVDC Gotland link (Gotland 1) went into service in 1954. It could transfer 20 megawatts over a 98-kilometer-long submarine cable between Västervik
Västervik Municipality
Västervik Municipality is a municipality in Kalmar County, south-eastern Sweden, with its seat in the city of Västervik....
on the mainland and Ygne on the island of Gotland
Gotland
Gotland is a county, province, municipality and diocese of Sweden; it is Sweden's largest island and the largest island in the Baltic Sea. At 3,140 square kilometers in area, the region makes up less than one percent of Sweden's total land area...
, with a voltage of 100kV. As a static inverter
Inverter (electrical)
An inverter is an electrical device that converts direct current to alternating current ; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits....
, Mercury arc valve
Mercury arc valve
A mercury-arc valve is a type of electrical rectifier used for converting high-voltage or high-current alternating current into direct current . Rectifiers of this type were used to provide power for industrial motors, electric railways, streetcars, and electric locomotives, as well as for...
s were used.
In 1970 the service was re-engineered to transmission capacity of 30 megawatts at a voltage of 150kV by using the first thyristor
Thyristor
A thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased .Some sources define silicon controlled rectifiers and...
module for HVDC applications.
However even this capacity was not high enough and in 1983 a new monopolar link, HVDC Gotland 2 with a transmission capacity of 130MW and a transmission voltage of 150kV was estalished. It consists of a 92.9 kilometers long cable with a single copper conductor of 800 mm2 cross section, from which 92 kilometres are submarine and 0.9 kilometres underground. Beside this, HVDC Gotland 2 has a 6.6 kilometres long overhead powerline section between Västervik static inverter plant and the Swedish Coast. It has 2 Aluminium conductors each with a cross section of 910 mm2, which are installed on wooden poles - perhaps the only HVDC powerline using such poles. In 1987 HVDC Gotland 3, a further monopolar link, with a transmission capacity of 130MW and transmission voltage of 150kV was installed. It consists of a 98 kilometers long cable with a single copper conductor of 800 mm2 cross section. 92 kilometres of this cable are laid in the sea and 6 kilometres underground on land.
The grounding electrode of the Västervik Inverter Station is situated at Almvik on Östra Eknö, that of Ygne Inverter Station at Gravfält. Both electrodes are used for Gotland 2 and Gotland 3 and are situated in sea-water filled basins close to the sea. At Almvik there are 2 such bassins, while Gravfällt uses only one. The basin design of the electrodes prevents fishes from getting too close to the electrodes, which may harm them.
Almvik electrode is connected with Västervik Inverter Station by an 18.95 kilometres long line with 4 overhead line and 3 submarine cable sections for strait crossings. The overhead line sections, which have a total length of 17 kilometres are installed on wooden poles and consist of 2 Aluminium conductors each with 910 mm2 cross section. The total length of the cable sections amounts to 1.95 kilometres and consist of 2 cables each with 1000 mm2 cross section. The connection between Ygne Inverter Station and Gravfält Electrode has a length of 12.75 kilometres. It consists of a 12 kilometres long overhead line on wooden poles, which uses 2 Aluminium conductors each with 910 mm2 cross section and a 0.75 kilometres long underground cable consisting of 2 Aluminium conductors each with 1000 mm2 cross section.
Sites
| Site | Coordinates |
|---|---|
| Västervik HVDC Static Inverter | 57°43′41"N 16°38′51"E |
| Händelöp HVDC Gotland 2 Cable Terminal | 57°41′07"N 16°42′47"E |
| Lilla Nävelsvik Electrode Line Terminal | 57°40′57"N 16°38′22"E |
| Narsvik Overhead Electrode Line Terminal | 57°40′41"N 16°38′19"E |
| Grönvall Overhead Electrode Line Terminal | 57°38′54"N 16°37′25"E |
| Grytsholmen Overhead Electrode Line Terminal | 57°38′42"N 16°37′21"E |
| Hamudden Overhead Electrode Line Terminal | 57°36′29"N 16°39′33"E |
| Västerbofjärden Overhead Electrode Line Terminal | 57°36′10"N 16°40′25"E |
| Almvik Electrodes | 57°34′32"N 16°41′49"E ; 57°34′29"N 16°41′50"E |
| Ygne HVDC Static Inverter | 57°35′13"N 18°11′44"E |
| Gravfält Electrode | 57°30′52"N 18°6′35"E |