Compact grid nodes for low-loss electricity transmission

Gas-insulated switchgear up to 320 kV is ready for the market

Until recently, space-saving gas insulation has not been available for DC transmission – only space-consuming air insulation. A research project led by Siemens has now managed to design such components. “The gas insulation enables us to achieve space savings of up to 95 per cent,” says Imamovic, whereby the direct current places other demands on the insulation than alternating current. The engineers are relying here on so-called RIP technology (Resin Impregnated Paper), which enables optimised field control in smaller system geometries.
Since all live parts are fully encapsulated, the system modules can also be installed outdoors, which means that the space required for a protective building is no longer required. The “space requirement” criterion is especially important for converter stations located in urban centres and on the collection platforms for offshore wind farms at sea. Switchgear for the voltage level up to 320 kilovolts has already been developed to market maturity. Based on long-term tests that are currently being carried out at the Technische Universität München, the researchers expect a lifespan of up to 50 years.
The engineers are now further developing the systems for the 500-kilovolt voltage level. The presented joint project on compact systems for high-voltage direct current transmission applications (abbreviated to DCCoS) is being funded by the German Federal Ministry for Economic Affairs and Energy.