The dynamic characteristics and structural responses of operation and grid loss offshore wind turbines (OWTs) under onshore and seafloor earthquakes are analyzed based on the established coupled seismic analysis model. In addition to the remarkable influence of the rotor system on the responses of the operation OWT under earthquakes, interactions among the natural modes of the grid loss OWT in the fore-aft and side-to-side directions are revealed. By comparing with the onshore earthquakes, the more significant differences of structural response are observed under the selected seafloor earthquakes, due to the longer duration and more abundant energy distribution around the natural frequencies of OWT. Concurrently, a multiple tuned mass damper (MTMD) is designed and applied to the operation and grid loss OWTs. Then, the comparisons of the mitigation effects under onshore and seafloor ground motions are carried out, and the necessity of applying seafloor ground motions to OWTs are proved. Moreover, in comparison to the operation OWT, more effective reductions are observed for the grid loss OWT under onshore and seafloor earthquakes using the designed MTMD. Therefore, the combined shutdown procedures and MTMD vibration control strategy is suggested for OWTs under earthquakes.

基于建立的耦合地震分析模型，分析了陆上和海底地震作用下运行和网损海上风力发电机组的动力特性和结构响应。除了转子系统对地震下运行的OWT响应的显着影响外，还揭示了电网损耗OWT在前后和左右方向上的自然模式之间的相互作用。通过与陆上地震的比较，由于 OWT 固有频率周围的持续时间更长且能量分布更丰富，因此在选定的海底地震下观察到结构响应的更显着差异。同时，设计了多调谐质量阻尼器（MTMD）并将其应用于操作和电网损耗OWT。然后，对陆上和海底地震动的缓解效果进行了比较，证明了海底地震动应用于OWT的必要性。此外，与运行OWT相比，使用设计的MTMD可以更有效地降低陆上和海底地震下的电网损耗OWT。因此，建议地震条件下的 OWT 采取联合停机程序和 MTMD 振动控制策略。