The extra-high voltage line in the Swiss Engadine between Pradella/Scuol and La Punt represents a bottleneck in the Swiss and the European transmission grid. To remedy this shortcoming, TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), began upgrading the 380kV line to 2 x 380kV in October 2017. This will increase import capacity from the north, strengthen interconnections with Austria and Italy and facilitate the transport of hydropower in the canton of Grisons. The project also improves security of supply in Switzerland and is part of the “Strategic Grid 2025”, Swissgrid’s ambitious modernisation and expansion plan.
Basically, the upgrade means that Swissgrid will attach a second 380kV line to the pylons, which are originally fitted with only one line on one side. Over the past two years, the TSO has reinforced the mast foundations between Pradella and La Punt and will complete this work in autumn. But Swissgrid has also examined the static of the pylons and discovered that some of them have insufficient load capacity for the second circuit. For safety reasons, it was thus decided to replace 50 of altogether 127 masts instead of reinforcing them. This change has no impact on the routing, but on the schedule: The commissioning of the upgraded line will be delayed by at least one year and is now planned for 2022.