Abstract Over 30% worldwide installations of wind turbines in cold climate regions are threatened with icing risks. The current study presents a systematic characterization of the turbine operation, power production, and blade/tower structural responses of a utility-scale wind turbine (2.5 MW, variable-speed variable-pitch regulated) under natural icing environments, by leveraging the unique facilities at the Eolos Wind Energy Research Field Station. A representative icing event that lasts 51 h is selected and divided into pre-icing, operational-icing, stopped-icing, and post-icing phases based on the variation of turbine operational conditions (i.e., power, rotor speed, and pitch angle) for the detailed evaluation. The results show that ice accretion can lead to appreciable reductions in the rotor speed and pitch angle before the turbine reaches its operational limits. Such reductions increase correspondingly as the inflow wind speed increases, which may accelerate the airfoil stall process and result in more severe power loss. The 51-h icing event yields a total energy loss of ~25 MWh, and the post-icing phase contributes a second-largest share of 17%, on the heel of the stopped-icing phase of 71%, associated with the long duration of natural ice melting process. Besides, blade structural response is highly sensitive to the ice accretion due to its fast reaction to the ice-induced lift penalties. The tower response also provides concrete evidence for the increase of the structural imbalance with ice accretion. Our findings can provide insights into the development of advanced control strategies for a more efficient and safer operation of wind turbines in natural icing environments.

中文翻译：

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自然结冰环境中的风力涡轮机性能：现场表征

摘要 在全球寒冷气候地区安装的风力涡轮机超过 30% 受到结冰风险的威胁。当前的研究通过利用独特的设施，在自然结冰环境下对公用事业规模风力涡轮机（2.5 MW，变速变桨调节）的涡轮机运行、电力生产和叶片/塔架结构响应进行了系统表征。在 Eolos 风能研究现场站。根据涡轮机运行条件（即功率、转子速度和桨距角）的变化，选择持续 51 h 的代表性结冰事件并分为预结冰、运行结冰、停止结冰和后结冰阶段用于详细评估。结果表明，在涡轮机达到其运行极限之前，积冰会导致转子速度和桨距角显着降低。这种减小随着流入风速的增加而相应增加，这可能会加速翼型失速过程并导致更严重的功率损失。51 小时的结冰事件产生了约 25 MWh 的总能量损失，而后结冰阶段贡献了 17% 的第二大份额，紧随停止结冰阶段的 71% 之后，与持续时间长有关自然融冰过程。此外，叶片结构响应对积冰高度敏感，因为它对冰引起的升力惩罚反应迅速。塔的响应也为结构不平衡随着积冰的增加而增加提供了具体证据。