Onshore converter for the Combined Grid Solution

31.01.2020

The Danish-German Combined Grid Solution (CGS) in the Baltic Sea is the world’s first offshore interconnector to use national grid connections of offshore wind farms to link the transmission systems of two countries. For this purpose, submarine cables were laid between the offshore transformer stations of the German wind farm Baltic 2 and the Kriegers Flak wind farm in the Danish part of the Baltic Sea. The CGS is a joint project of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), and TSCNET customer Energinet, the TSO from Denmark.

The Bentwisch substation near the Baltic port city of Rostock houses the German onshore converters for the CGS. Here 50Hertz has installed a double converter system including a back-to-back converter. This is essential for balancing the asynchronous transmission systems of Germany and Eastern Denmark: The AC from the Nordic synchronous area is converted into DC and directly back into AC, now adapted to the European synchronous area.

50Hertz has now successively energised and commissioned all converter components in Bentwisch. The new equipment and further extensions of the substation had to be individually synchronised with the control technology in a series of individual testing and commissioning steps. The operational readiness of the double converter system in Bentwisch marks another important milestone on the way to the commissioning of the entire CGS.

The German onshore converter for the Danish-German offshore interconnector Combined Grid Solution has been commissioned by 50Hertz (picture: Jan Pauls / 50Hertz)

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