Statnett and Statkraft

Rehabilition of a switching station

Omexom Norway has a broad portfolio of competent and knowledgeable employees within the entire value chain of energy distribution. One of them is Lars-Johan Knudsen.

Inside the Skjomen power station outside Narvik, northern Norway, Lars-Johan Knudsen stands and follows the instrument panel on a Dilo service trolley. It is used to process gas – be it moving, emptying or cleaning without any SF6 gas escaping into the open air. The service trolley can also vacuum gas chambers for air.

Statnett and Statkraft are in the process of rehabilitating the entire Skjomen switching station, and have, among other things, invested in a new ABB 145 GIS facility. The old GIS plant must therefore be condemned. Omexom ensures safe drainage of the gas in the plant. In total SF6 gas must be emptied from 90 chambers, divided into 7 fields.

SF6 gas is used as insulation and quench / extinguish dangerous arcs that can occur in electrical systems like this at Skjomen. Much of the reason SF6 gas is used is that it is very space-saving. Air-insulated plants take up much more space, says Knudsen, who is also a member of the national “User group for gas-insulated switchgear”, where knowledge, experiences and issues related to operation, maintenance and development of GIS plants are exchanged. SINTEF in Trondheim is the secretariat for the user group.

And just SINTEF s Magne Runde holds certification course in SF6 treatment with Omexom and Statnett.

Strict requirements are set for handling and reporting of the SF6 gas and careful monitoring and measurements of gas quality must be conducted. All personnel working with SF6 gas in high voltage installations must be certified and approved, with both practical and theoretical tests. And the certificate must be renewed every five years, says Knudsen.

“In Omexom Norway, we want to contribute to sustainable development in this field as well. We use Omexom’s international network of expertise to monitor and participate in the environmental change that is going on in the future. Gas-insulated plants with more environmentally friendly gases than SF6 are now being installed in Norway. The field is constantly evolving”, says Lars-Johan Knudsen, who also contributes to reuse the system.

The gas we extract from the old plant in Skjomen is transported to Germany, where the gas is purified. The gas is then recycled, so our expertise in the area helps to reduce the total use of SF6, Knudsen concludes.

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