Statnett Energizes 420 kV Aurland-Sogndal Transmission Upgrade Across Challenging Fjord and Alpine Terrain

Norway’s transmission system operator Statnett has fully commissioned and energized the upgraded 420 kV Aurland-Sogndal transmission link in Vestland county,...

Statnett Energizes 420 kV Aurland-Sogndal Transmission Upgrade Across Challenging Fjord and Alpine Terrain

Norway’s transmission system operator Statnett has fully commissioned and energized the upgraded 420 kV Aurland-Sogndal transmission link in Vestland county, reinforcing bulk hydropower transmission capacity across the Sognefjord and securing power supplies for green industrial electrification.

Engineering Triumph Over Glacial Slopes and Fjord Spans

Completed on October 1, 2026, the Aurland-Sogndal project replaces aging 300 kV infrastructure with a heavy-duty 420 kV transmission corridor traversing rugged western Norwegian mountains at altitudes exceeding 1,400 meters.

The project features spectacular long-span aerial conductor crossings across the deep Sognefjord, utilizing specialized composite-core reinforced aluminum conductors designed to withstand extreme rime ice loading (>12 kg/m) and hurricane-force Arctic gale winds.

Substation Expansions at Aurland and Sogndal

The upgrade necessitated comprehensive expansions at both the Aurland underground cavern substation and the Sogndal regional grid hub. Statnett installed low-noise 420 kV shunt reactors, high-speed SF6-free circuit breakers, and upgraded digital protection relays with IEC 61850 Process Bus architecture.

The increased voltage rating enables the unconstrained evacuation of over 2,200 MW of flexible mountain hydropower, wheeling clean baseload power toward eastern consumption hubs and international interconnections.

Supporting Nordic Energy Security and Industrial Electrification

Statnett emphasized that the energized corridor eliminates long-standing western bottlenecks, facilitating the grid connection of shore-to-ship maritime power stations, aluminum smelter decarbonization projects, and localized data center clusters.