Harmonic suppression strategy for faults in offshore wind power grid connected systems involving energy storage

After a fault occurs in the receiving-end grid of an offshore wind power transmission system based on voltage source converter-based high voltage DC (VSC-HVDC), it not only affects the frequency stability of both the AC and DC sides of the receiving-end converter station but, in severe cases, may also hinder the normal operation of the sending-end converter station and offshore wind turbines. Therefore, this paper first analyzes the propagation mechanism of asymmetric faults in the receiving-end grid of an offshore wind power transmission system. Then, a coordinated control strategy involving energy storage is proposed. Finally, simulations are conducted to evaluate the effectiveness of the proposed control strategy under a single-phase-to-ground fault in the receiving-end grid. The results demonstrate that the proposed strategy effectively suppresses higher-order harmonics and enhances system frequency stability.