Transient stability enhancement of multi-infeed AC offshore islands for large-scale HVDC interconnection and wind integration

The integration of large-scale offshore wind farms with HVDC interconnections is crucial to achieving the energy transition goals. These systems often configured as AC offshore islands, encounter complex challenges during transient disturbances, including AC and DC faults. Existing approaches inadequately address the challenges of multi-infeed configurations where multiple HVDC links connect to adjacent AC buses. To fill this gap, this paper introduces a coordinated control strategy aimed at enhancing the transient stability and resilience of multi-infeed AC offshore islands. The proposed strategy utilises advanced control functions, including consideration of Fault Ride Through (FRT) capability, P/f droop control, alongside a master controller, to improve fault response and system recovery. The FRT function is essential for enabling the system to ride through faults and recover, while P/f droop control aids in curtailing power during imbalances caused by HVDC disconnections. A master controller refines system stability by dynamically adjusting post-fault control set-points . Validated through extensive simulations in PSCAD/EMTDC, this strategy demonstrates robust resilience across various transient scenarios, underscoring its potential for broader implementation in offshore power systems.