2 GW Offshore and Onshore Converter System – North Sea Connector 2

Pursuant to §17d EnWG, transmission system operators must construct and operate offshore connections as defined in the German Grid Development Plan (NEP) and the Site Development Plan (FEP) according to §5 WindSeeG. In this context, 50Hertz is responsible for the offshore grid connection for the two offshore sites N-12.4 and N-12.5. The planned total generation capacity of the two offshore sites N-12.4 and N-12.5 amounts to 2 GW. Therefore, 50Hertz introduced the project NSC2 which will connect the two wind farm sites to the onshore grid. The grid connection system will be realised with 525 kV DC technology and a transmission capacity of 2 GW with a required Readiness-for-Trial-Operation in 03/2034. NSC2 comprises the projects LanWin6 and DC32 and is integrated into the NordHub. The scope of all three projects is briefly described in the following. The LanWin6 project (defined as project NOR-12-3 in the NEP) aims at the connection of the two offshore wind farm sites N-12.4 and N-12.5 via an offshore converter station and a DC sea and land cable connection to a Multiterminal Hub. The offshore wind farms will be connected via a 132 kV (AC) direct connection to the offshore converter station. The Multiterminal Hub, to which LanWin6 is connected to, is planned in the Pöschendorf search area and is called NordHub. It will be designed as a 4-terminal hub, i.e. it will integrate the two converters of the NSC2 project and the two converters of the LanWin7 project (developed by German TSO TenneT to connect other offshore wind sites), respectively offshore and onshore, in a DC-switching station. The necessary MTDC technology standards, including but not limited to the HVDC system and control and protection requirements, are being developed in an ongoing ‘Innovation Partnership’ project of the four German TSOs with HVDC OEMs. This partnership aims at defining the basic design for the Multiterminal Hubs, prequalifying the required DC circuit breakers and providing the MT