Offshore electrical grids are growing rapidly in order to transmit offshore generated wind power to loads onshore. Future offshore electrical systems will become more complex. It will consist out of a mix of HVAC technology and HVDC technologies. In current outlooks, offshore system can also be used to further increase interconnection between coastal regions. In addition, also large scale offshore hydrogen production will be introduced using PEM technology. Many challenges exist in designing these future system. Firstly, the envisioned scale of electrolysis has not been implemented in any electrical system. Although aggregation methods of validated smaller scall models is widely used, validation of larger scale models is essential for the implementation in offshore systems. Secondly, coordinated fast active power flow control system need to be developed. The offshore system should be able to work in a stable manner when it is faced with disturbances. Lots of work has been performed in handling of fault conditions for both HVAC and HVDC offshore systems. In an integrated system, also the active power of all relevant components has to be controlled in coordinated fashion. This will also enable frequency support to the onshore AC grid. However, grid codes require fast response times which require fast response of all component in the offshore system.
This presentation presents a synthetic model built in RSCAD, which is intended as a platform for investigating the above indicated challenges. The model consists of bipolar MMC HVDC links connecting the onshore AC system to an offshore AC system. The offshore system includes 2 GW of wind generation and different sizes of electrolyzer models.
Cees van Vledder | TU Delft