In the long-term, the modal properties of Offshore Wind Turbines (OWT) exhibit significant variations due to constant changes in environmental and operational conditions. These variations have a substantial effect on the wind turbine loads and will lead, for instance, to large uncertainty in fatigue and useful life predictions. Due to the numerous sources of uncertainty, it is difficult to judge how independent environmental or operational parameters influence the modal properties of OWTs. In this work, we make a systematic analysis of the modal parameter estimates extracted from a long-term monitoring campaign in an OWT from the DanTysk wind farm while in its idling condition. We cluster the dataset of vibration responses of the idling OWT into bins of wind and wave characteristics, in order to isolate the effect of the different sources of uncertainty affecting the OWT modal properties. Once the trends in the data are confirmed, we use a simple linear regression model to extrapolate the damping estimates for zero wind speed and wave excitation, thus providing an estimate of the mean and standard errors of the OWT structural damping in the first fore-aft and side-to-side tower bending modes.

从长远来看，由于环境和运行条件的不断变化，海上风力涡轮机 (OWT) 的模态特性会发生显着变化。这些变化对风力涡轮机负载有重大影响，例如，会导致疲劳和使用寿命预测的很大不确定性。由于不确定性来源众多，很难判断独立的环境或操作参数如何影响 OWT 的模态特性。在这项工作中，我们对从 DanTysk 风电场 OWT 的长期监测活动中提取的模态参数估计值进行系统分析，该监测活动处于闲置状态。我们将空载 OWT 的振动响应数据集聚类到风浪特征的箱子中，为了隔离影响 OWT 模态特性的不同不确定性来源的影响。一旦数据趋势得到确认，我们将使用简单的线性回归模型来推断零风速和波浪激励的阻尼估计值，从而提供第一次前后 OWT 结构阻尼的平均值和标准误差的估计值和左右塔弯曲模式。