地震动方向对海上风力发电机动力响应的影响

Effects of ground motion input direction on dynamic response of offshore wind turbine

叶轮-塔架耦合及气动阻尼作用使得海上风力发电机前后向、侧向动力特性存在差别。针对NREL 5 MW单桩式海上风力发电机,通过理论分析,探讨海上风力发电机前后向与侧向振型、阻尼特性的差异;然后,针对停机和运行两种工作状态,采用气动-伺服-水动-弹性完全耦合方法,分析输入地震动方向影响海上风力发电机结构动力响应的规律,探讨最不利方向;最后,还分析了平均风速对最不利输入地震动方向的影响。结果表明:输入地震动方向可能显著影响海上风力发电机支撑结构泥面弯矩和塔顶位移幅值;对于运行状态,强震作用下,侧向为最不利输入地震动方向,弱震作用下,前后向为最不利输入地震动方向。

Due to impeller-tower coupling and aerodynamic damping,dynamic characteristics of an offshore wind turbine in forward-backward direction and those in lateral direction are different.Here,for a 5 MW NREL single pile type offshore wind turbine,through theoretical analysis,differences of vibration mode and damping characteristics of the turbine between its forward-backward direction and lateral direction were explored.Then,under the two working conditions of shutdown and operation,using the aerodynamic-servo-hydrodynamic-elastic fully coupled method,influence laws of ground motion input direction on dynamic response of offshore wind turbine structure were analyzed to explore the most unfavorable direction.Finally,effects of average wind speed on the most unfavorable input direction of ground motion were analyzed.The results showed that the input direction of ground motion may significantly affect the mud surface bending moment and tower top displacement amplitude of offshore wind turbine support structure;under the operation working condition,the lateral direction is the most unfavorable ground motion input direction under action of strong earthquake,the forward-backward direction is the most unfavorable ground motion input direction under action of weak earthquake.