Four high-voltage power cables for exchange of energy between Denmark and Sweden have been successfully replaced with new 400 kV XLPE HVAC power cables.

Since 1915 the power grids of Sweden and Denmark have been connected by a power cable providing exchange of energy between the neighbouring countries. NKT has completed the replacement of four high-voltage power cables installed in 1973 with four new 400 kV XLPE HVAC power cables.

Tight time schedule

For NKT, the project was executed successfully according to the tight time schedule and the new power cables for the historical power link are now in full operation.

Interconnectors are essential to the power cable infrastructure needed to ensure an efficient integration of the increasing amount of renewable energy produced in Europe.

"We are happy to upgrade the cables across Öresund playing a key part in maintaining the high transmission security of both countries and to strengthen the interconnection of the European power grids," said executive vice-president Claes Westerlind, head of the Swedish high-voltage NKT factory in Karlskrona.

The power link across Öresund is owned by the Swedish national grid operator Svenska Kraftnät that awarded NKT the project in a consortium with Boskalis.

Replaced original oil-filled cables

In joint effort the two companies successfully replaced the original oil-filled cables with four new 400 kV XLPE HVAC power cables in close collaboration with Svenska Kraftnät and Energinet in Denmark. The new cables were manufactured at the company’s high-voltage power cable factory in Karlskrona, which is running on 100% green electricity.

When installed in 1973, the power cables now replaced were the world’s first low pressure oil filled power cables installed offshore at this voltage level.

They were produced by the cable division within ASEA – a unit now part of NKT. In collaboration with Boskalis, NKT removed the old power cables which were send for recycling before the new power cables were installed at the same location and connected to substations at the shores on both sides.