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Estlink 2 underground cableAseri county and Lüganuse county, Ida-Virumaa

Estlink 2 is the second direct current connection between Estonia and Finland, which effectively trebles the transmission capacity between the Baltics and Nordics and which means that Estonia and Finland have become a single market area. The capacity of Estlink 2 is 650 MW, which allows covering half of the electricity needed by Estonia in the winter months. The total length of Estlink 2 is about 170 km. On the Estonian side, it starts from Püssi substation in Ida-Viru County, which is one of the strongest central substations in Estonia’s power system. Under the Estlink 2 project, a converter station was built next to Püssi substation, from which point a land cable runs for 12 km to the shore of the Gulf of Finland and continues as a subsea cable. The sea cable, which is installed at a depth of up to 90 metres, runs along the seabed for 145 km until it reaches Finnish soil, where it continues as a 14 km overhead line to Anttila converter station. Whereas the undersea part of Estlink 2 has both circuits running in the same sheathing, in the land part of the cable this solution is replaced by two parallel cables. Thus three different types of cables can be distinguished in the Estlink 2 transmission line:
• subsea cable (145 km)
• land cable main current circuit cable (12 km)
• land cable reverse current circuit cable (12 km)
The land cables were installed in pipes throughout the length of the cable clearance. Eleven kilometres of the line was built using the open method and 1 km using horizontal drilling. Access roads were also needed to build the lines and drag the cables into them. A total of 3 km of such roads were built, of which 2.5 km were actually utilized. The Merko Infra contract also included transport of the land cables from the Port of Sillamäe to the working area. The drums came in two sizes:
• 12 of them for the main cable D=5.5m weight 55 tonnes
• 12 of them for the reverse cable D=3.7m weight 25 tonnes

Client:
Nexans Norway AS
Name of the project:
Estlink 2 underground cable
Category:
Civil engineering
Type of construction:
Power infrastructure
Designer:
Nexans Norway AS
Description of work:
New building
Country:
Estonia
Address:
Aseri county and Lüganuse county, Ida-Virumaa
Beginning of the project:
2011
Completion year:
2014
Characteristic feature:
12 km of 450 kV direct current cable line between Estonia and Finland