Hydropower in the mountains at Trollheim

Jan 30, 2023

Partly hidden away inside the mountain area of ​​Trollheimen, in Surnadal municipality in Møre og Romsdal, is the Trollheim hydropower plant.

Trollheim was built in the 60s, and is owned by Statkraft. It is the second largest hydropower plant in Møre og Romsdal and accounts for 12% of the county's power production.

After 60 years of steady operation, it is now time for upgrades. The plant must be prepared to meet future energy and safety needs. Therefore, in recent years, Trollheim has carried out several major upgrades of critical infrastructure.

One of the projects included upgrading the 132 kV cable system from an oil cable system to a new PEX cable system.


Technical competence - an important factor

Statkraft chose LOS Cable Solutions as total supplier for this assignment, and Nexans was chosen by LOS as manufacturer and supplier of cable.

“ Nexans provided many resources to follow up the project. It all felt very safe ”

Merethe Kværner Ulsrød

Project Manager in LOS

Merethe Kværner Ulsrød, project manager at LOS, says that high technical competence was one of the most important reasons why Nexans was chosen. It was also an important factor for LOS that they had good resources at their disposal through the collaboration for technical clarifications with the client.

– It has been an advantage to have a local, Norwegian supplier that we could easily contact, without it being a criterion from our side when awarding. In addition to the fact that Nexans provided many resources to follow up the project. It all felt very safe, says Ulsrød.

Final product

The project entailed a major risk for Statkraft to be able to start production as planned after the upgrade. One of the major milestones between Statkraft and LOS was that the new cable had to be delivered before disconnection. This as a risk-reducing measure and to ensure that there were no delays.

Then, in September 2022, three drums were delivered to Surnadal/Sunnmøre - at the agreed time. Each drum contained 650 meters of cable which will contribute to future power production.

The cable supplied was a TSLI 170 kV 1x800 mm2 A/95 with aluminum conductor, copper screen and a flame retardant outer jacket. The cable was produced in our factory in Cortaillod in Switzerland.

In addition, the cable came with an integrated fiber optic cable. It allows Statkraft to potentially monitor the temperature in the cable so that they can avoid destructive overloads.

After a final final test in December, the cable is now finally delivering power to central Norway. Something it will also be allowed to do for many more years.

Easy to work with 

Another challenge that had to be solved: A cable route that had several differences in height and contained many turns and bends.

Merethe says that in the end the result was more than acceptable:

– I have received good feedback from those who worked with the cable. Among other things, the plant managers were very satisfied with the cable, it was good to work with and was "willing to cooperate". Here there may be a slight difference from the manufacturers.

Want to work together again

– There were many technical clarifications from the client along the way. It was important to have Nexans available in these clarifications. Through good follow-up, we were able to clarify important practical and empirical questions that arose, says Merethe about what was to become an extra important factor for her through the Trollheim project.

“ LOS wants good and solution-oriented partners in all stages of our deliveries and this reference with Nexans makes it appropriate to continue in future projects ”

Merethe Kværner Ulsrød

Project Manager in LOS

All in all, it has all been a good and educational experience for all parties, with good cooperation.

– It has been a long project with a learning process for both of us. My colleagues and I have learned a great deal from Nexans throughout the process, and I think Nexans has gained more insight into the practicalities of a cable installation and what is important to the client in a facility that is built to last for decades to come.

– LOS wants good and solution-oriented partners in all stages of our deliveries and this reference with Nexans makes it appropriate to continue in future projects, she concludes.

Sales & Project Manager Bård Lillehaug has been LOS's main contact in Nexans, and thanks him for the trust in Nexans being chosen as supplier of cable for this project for Statkraft. Bård also takes the opportunity to thank for constructive and good cooperation throughout the entire project period, right from the offer phase in summer 2021 until handover in autumn 2022.

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