New power line for supply security in the Schwanden

The grid operators SN Energie, tbgs, tb.glarus and Axpo have realised a new power line in record time. Together they overcame the damage to the grid infrastructure caused by the landslide in Schwanden. The new line with an operating voltage of 16 kilovolts (kV) restores a high level of supply security in the Schwanden area and the Sernftal valley.

On 29 August 2023, a landslide occurred in the Wagenrunse area above the village of Schwanden in the municipality of Glarus Süd. The landslide damaged the 50 kV Axpo cable line and the 16 kV cable line of the Glarus Süd Technische Betriebe Glarus Süd between the Schwanden and Linthtal substations. They could no longer be operated. 

The two power lines are important for a high level of supply security in the Schwanden area and in the Sernftal valley. The responsible grid operators SN Energie, Technische Betriebe Glarus (tb.glarus), Technische Betriebe Glarus Süd (tbgs) and Axpo therefore reacted immediately and decided to build a new 16-kV cable line around four kilometres long. The new power line connects the Schützenhaus switching stations of tb.glarus in Glarus and the Doppel-power transformer station in the tbgs network in Mitlödi.

Rapid realisation

In cooperation between SN Energie, tb.glarus and tbgs and with the support of Axpo, the new cable line was planned, approved and realised in a record time of just over two months. The new 16 kV cable line runs for the most part in an existing pipe system parallel to the 50 kV Löntsch-Schwanden cable line of SN Energie. To pull in the cables, the recently constructed pipe system had to be opened up again at the so-called pull shafts.

Peter Moos, Head of Operational Asset Management at Axpo Grid: "The quick reaction and cooperation illustrate the commitment and dedication of the companies involved to continuously guarantee the energy supply in the region."

Unrestricted power supply

In the event of an unplanned interruption to the 50 kV Löntsch-Schwanden cable line, the operational 16 kV cable line enables the Schwanden area and the Sernftal valley to be supplied with electricity again without restriction after a short switchover. It will make a significant contribution to stabilising the power supply again and ensuring a high level of security of supply for local residents. The line can also be used in the event of unexpected supply bottlenecks in the Glarus area. SN Energie has taken over the project management for the construction of the 16 kV cable line. Axpo financed the costs of around CHF 1 million. tb.glarus and tbgs own the line and are responsible for its operation and maintenance.

The repair of Axpo's damaged 50 kV cable line and tbgs' 16 kV cable line between the Schwanden and Linthal substations is currently being planned. The repair is scheduled for implementation in summer/autumn 2024.