High-voltage transmission line, Sweden

The 145 kV transmission line between Munkfors and Deje needed to be rebuilt. The project had a tight timeframe and the route passes through urban areas, including residential areas, which placed higher demands on all involved.

- The old line was outdated, last renovated in the 1950s, and needed to be replaced. However, as the route passes through urban areas, we cannot build a new overhead line along the entire route with today's requirements. Instead, we chose to undermine the cable in Munkfors and Deje," explains Tommy Nyhlén, project manager at Ellevio.

After tendering, Ellevio chose to place the purchase of the cable with the contractor, which became Linjemontage. The assignment came in the autumn of 2021 and the first delivery was to be made in the spring of 2022. A tight timeframe that required a lot of cooperation and close dialogue. Linjemontage contacted NKT together with Ahlsell.

– After obtaining the contract, we chose NKT as a supplier of cable and accessories. Partly for a favorable price and quality but also to minimize the environmental impact. Since the cable is manufactured at the NKT factory in Falun, Sweden, we get a shorter transport of the 72 drums, weighing more than 6 tons each. Despite the short delivery time, it has been possible to deliver without slowing down the progress of the project, says Johan Holmgren, project manager at Linjemontage.

Prior to the start of the project, calculations and planning were of particular importance to NKT.

– We really wanted to make sure that we could deliver within the tight timeframe. 145 kV cable with area 1600 mm2 is not something we have in stock so we wanted to make sure that we could produce everything on time. That's an important aspect, that the customer can rely on us," says Mikael Åkerlund, Key Account Manager at NKT.

Six parallel cables were laid over a distance of 5,700 meters, making a total of almost 35,000 meters of cable installed in the project. The work was tight in places because the pipes had to be laid in the middle of residential areas.

– It was solved with smaller machines that are easier to maneuver and a good cooperation, says Lars-Ove Larsson, Key Account Manager at Ahlsell.

The reinforcement of the Munkfors-Deje transmission line is not just to replace older, obsolete lines. The project will reduce the risk of power cuts and provide even better opportunities for installing solar cells and electric car charging stations. It has also increased capacity and developed opportunities for larger-scale electricity production, which will benefit many people in the energy transition.

– They want to expand the electricity production even more, so we would like to increase our subscription to Svenska Kraftnät, but we can't do that right now because their networks are not sufficiently developed. So for the time being, we need to upgrade regionally instead. The industries here, the paper mills for example, will also benefit greatly from this reinforcement," says Tommy Nyhlén.

With regard to the delivery time, it was very advantageous for the project that it was possible to use Swedish production. All cables for the project were produced in Falun and all accessories in NKT's factory in Alingsås.

– The fact that we have this type of production in Sweden is very exciting and it has many advantages, NKT's factory in Falun, for example, uses only green electricity, says Mikael Åkerlund at NKT and he is supported by Lars-Ove Larsson at Ahlsell.

– It's a great strength to be close to production. That way, quick action can be taken if something unexpected happens.

According to the original schedule, the cable was to be commissioned in 2023, but thanks to a good dialogue between the companies involved, the first phase could be commissioned before Christmas 2022.

- The project, which is now entering its final phase, has gone very well. This is thanks to a good dialogue between the client and us as the contractor, we have together solved the problems that occurred during the project, which has given us a good working climate and good momentum, says Johan Holmgren.

- To be able to start commissioning already this year feels very successful. The deliveries from NKT have gone very well," says Lars-Ove Larsson.