针对以远海岛屿特殊地理环境为背景的海上风电经柔性直流输电并网系统的直流单极接地故障问题，提出了一种故障期间实现一半额定功率传输的容错运行策略，以减少停运损失，并提高受端电网安全稳定性。首先采用岛上风电侧半桥型模块化多电平换流器（modular multilevel converter，MMC）和岸上并网侧混合型MMC的输电拓扑，并分析了其直流线路故障特性；通过利用风电侧换流站可串联备用变压器组网方案，避免了风电场因低压脱网，实现了故障期间的直流持续降压运行；进而在岛上配置了风电侧直流耗能装置，解决了风电场长时间减载下风电侧换流站的能量盈余问题，使系统进入一半额定功率传输的容错运行模式。最后基于PSCAD/EMTDC仿真平台验证了所提远海岛屿海上风电经柔直并网系统直流单极接地故障下容错运行策略的有效性。

Aiming at the unipolar ground fault problem of offshore wind power grid-connected system via flexible HVDC transmission with the background of special geographic environment of remote islands, a fault-tolerant operation strategy to achieve half rated power transmission during faults is proposed to reduce the loss of outage, and to improve the security and stability of the power grid at the receiving end. Firstly, the transmission topologies of half-bridge modular multilevel converter （MMC） on the island wind power side and hybrid MMC on the onshore grid-connected side are adopted, and their DC line fault characteristics are analyzed; the series-connectable standby transformer networking scheme of the converter station on the wind power side is utilized to avoid wind farms going off-grid due to low-voltage, and to realize the continuous DC voltage reduction operation during the fault period. Further, a wind power side DC energy dissipation device is configured on the island to solve the energy surplus problem of the wind power side converter station under long time load shedding of the wind farm, enable the system to enter a fault-tolerant operation mode with half of its rated power transmission. Finally, based on the PSCAD/EMTDC simulation platform, the effectiveness of the proposed fault-tolerant operation strategy for offshore wind power grid-connected systems with flexible HVDC link under unipolar grounding faults in remote islands is verified.