Elering to install second 110-kilovolt Prysmian submarine cable in Suur Strait between the mainland and Muhu

12/08/2020 - 12:00 AM

This week, Elering will install the second 110-kilovolt submarine cable in the Suur Strait between substations on the mainland and on Muhu island in order to improve the security of supply of electricity for the residents of Muhu, Saaremaa and Hiiumaa islands; the installying of the cable will cost nearly nine million euros. The cable will be installed by Merko Infra and Connecto Eesti, with the cable being produced in the Finnish factory of the Prysmian Group. 

The new submarine cable will be laid in the Suur Strait between the Rõuste and Tusti substations, replacing the two old 35-kilovolt submarine cables, which are in need of replacement. The length of the new cable line is close to 11 kilometres, with the submarine section of cable 9.7 kilometres long. The laying of the cable started from Muhu Island where the submarine cable was floated a couple of kilometres into the sea by a cable layer and was then transported via floats to the shore where it will be connected with the cable line to Tusti substation. The second end of the cable will be connected to the land cable from Rõuste substation. A new substation was constructed for the cable at Rõusti substation.

The capacity of the new cable is 520 amperes, the diameter is 190 millimetres and the weight is 67 kilogrammes per metre. The cable will be laid into the sea as a single part, without extension couplings. A fibre-optic communication cable will be laid into the sea with the new cable. To avoid the risk of damaging the cable, it will be sunken 1-1.5 m into the seabed. The life of the new cables is 50 to 60 years and they have enough capacity to handle a notable increase in consumption.

The new cables are more sustainable than older cables as polyethylene insulation is used for them instead of oil impregnated paper.
Read more on the Elering website (in Estonian):
Elering improves the islands' security of supply with new submarine cable