Mission

MISSION is developing and demonstrating three SF₆-free switchgear components for the future AC (alternating current) and DC (direct current) systems.

The power system is undergoing significant changes due to decarbonisations. Between 2020 and 2030, European electric power generation is expected to increase by 25 to 30%, which will lead to a growth in the transmission grid. This new energy production will mainly come from renewable sources, such as offshore wind and solar-photovoltaic energy, which are often located in remote areas.

To prevent significant reactive losses during long-distance AC transmission of this renewable energy, there is a need to shift towards more HVDC connections and, eventually, develop an HVDC grid.

Most of today’s MVAC and HVAC switchgear is filled with the insulation gas SF₆ (sulphur hexafluoride). This is the most potent greenhouse gases: SF₆ is 24,300 worse than CO₂.

The expected grid expansion will result in a doubling of the banked volume of SF₆ by 2030 if executed with traditional technology. However, revised F-gas regulations have set end dates for the use of SF₆ in new switchgear in Europe: 2026 (up to 24 kV) and 2032 (over 145 kV). This is forcing transmission system operators (TSOs) to look for replacement technologies while expanding their grids.

The switchgear components that will be developed and demonstrated will enable emission-free energy transmission in a resilient and sustainable electric grid, eliminate the use of SF₆ and address critical technology gaps for AC and DC grids.

Through a multidisciplinary partnership of 12 partners from 9 countries, MISSION will type-test and demonstrate these three switchgear components:

• SF₆-free 420 kV live-tank circuit breaker with vacuum technology for high-power HVAC air-insulated substations. No such switchgear is yet available on the market, even though this is the most common type of switchgear in the European 420 transmission grid.
• SF₆-free 550 kV gas-insulated switchgear (GIS) with N₂/O₂ to ensure low space occupancy for offshore applications on platforms. Gas-insulated switchgear assemblies for DC are required for long-distance transmission of power such as on offshore HVDC converter platforms, where space is limited.
• an ultra-fast 12 kV MVDC circuit breaker for future MVDC grids. The expansion of DC power grids requires innovative components to safely manage the grid, and to be able to securely deliver power reducing the transmissions losses and minimising the out-of-service times.