Overview of the year

POWER LINES GO UNDERWATER

In 2020 Repower began reinforcing the section of line between Champfèr and Silvaplana. The 150 kV overhead line, the 60 kV cable line and sections of the 16 kV overhead line are being replaced and combined over long distances. The new cable line runs underground. In 2020 the 60 kV cable line was replaced. Part of this runs through a lake, Lej da Champfèr, and the tunnel of the new Silvaplana bypass. The 150 kV line will be continued separately, now as a cable line, to the Albanatscha substation.

Replacing the lines will improve the availability, security of supply and performance of the power grid in the St. Moritz Champfèr–Silvaplana area, as well as assuring efficient operation in the long term. In July the grid specialists were confronted with a fairly unusual job: running the new cable line through a lake, Lej da Champfèr. The cable conduit was first run along the surface of the lake before being lowered to the bed, supervised by professional divers. Repower worked closely with the authorities and specialists on the routing and construction of the new cable line, which takes equal account of the landscape, the environment, and the leisure and tourism infrastructure.

The new cable line takes account of the landscape, environment, and leisure and tourism

The project is headed by 35-year-old technical specialist Simon Nay.  Running a line through a lake is also a fairly unusual challenge for him. “The principle is actually simple: once the pipes are in the right position, they’re flooded and sink to the bed of the lake. Because of the strong Maloja wind, the challenge was to submerge the cable conduit in the right position.” The pipes laid in this way should last for at least two generations, or about 80 years.

Once the new cable line is in operation, in 2021 work will commence to dismantle the old 150 kV and the 16 kV overhead line. To upgrade the landscape in the Upper Engadine, a total of 13 pylons and 71 wooden poles will be removed. The investment for the new cable lines between Champfèr and Silvaplana comes to around CHF 7.2 million.

Investing in security of supply

Repower owns, maintains and builds distribution grids in the Prättigau, Rhine Valley, Surselva, Poschiavo and Engadine areas and invests around CHF 30 million a year in extending and maintaining its distribution grid. Replacing the lines between Champfèr and Silvaplana as described above will help improve the availability, security of supply and performance of the power grid in the Upper Engadine area, as well as assuring more efficient operation in the long term.

Simon Nay

Project head