Helwin Beta HVDC offshore converter platform

HelWin Beta forms part of TenneT’s offshore grid connection system in the German North Sea. TenneT, the project operator, appointed Siemens as the main contractor, who in turn subcontracted Heerema Fabrication Group (HFG) for the construction of the platform.

Iv was responsible for the detailed engineering and design of the topside, including the transport and installation design, workshop drawings for the grillages, the connecting bridge to the adjacent HelWin Alpha platform, and the procurement of non-high-voltage-related equipment. The jacket was engineered and designed by HFG Engineering.

The export route extends about 130 kilometres to the onshore converter station. This required highly efficient and reliable conversion to minimise transmission losses. The generated 33 kV AC from the wind turbines is first converted to 155 kV AC and then to 320 kV DC on the HelWin Beta platform.

During the conversion process, a significant amount of heat is generated. Iv designed the seawater cooling and HVA/C systems to ensure stable operation and maintain all equipment within the specified range of 18 to 25 °C.

As HelWin Beta operates unmanned and is remotely controlled from shore, all auxiliary systems had to be fully integrated and designed for long-term reliability.

With a transmission capacity of 680 megawatts, HelWin Beta supplies renewable energy to approximately 500,000 households. Together with HelWin Alpha, it strengthens the offshore energy infrastructure and contributes to a reliable and sustainable power supply for northern Germany.