Further Study on the Effects of Wind Turbine Yaw Operation for Aiding Active Wake Management

Abstract

Active wake management (AWM) via yaw control has been discussed in recent years as a potential way to improve the power production of a wind farm. In such a technique, the wind turbines will be required to work frequently at misaligned yaw angles in order to reduce the vortices in the wake area behind the turbines. However, today, it is still not very clear about how yaw operation affects the dynamics and power generation performance of the wind turbines. To further understand the effects of yaw operation, numerical research is conducted in this paper. In the study, the optimal size of the flow field used in the computational fluid dynamics (CFD) calculation was specifically discussed in order to obtain an efficient numerical model to quickly and accurately predict the dynamics and the performance of the turbines. Through this research, the correlation between the blade loads during yaw and non-yaw operations is established for aiding yaw control, and the blade loads and power generation performances of the wind turbine during yaw operation under different wind shear and blade deflection conditions are analyzed for understanding the effects of yaw operation. It is found that the optimal size of the flow field for performing efficient and accurate CFD calculations does exist. The misaligned yaw operation generally tends to decrease the loads acting on the blade. However, the aerodynamic energy captured by the turbine rotor and blade loads during yaw operation is not only dependent on the yaw angle of the rotor but is also affected by wind speed, rotor speed, the pitch angle of the blades, blade deflection, and wind shear. Particularly, it is interestingly found that wind shear can cause undesirable fluctuation of the power, which will challenge the power quality of the wind farm if no measures are taken.

Analysis of Wind Turbine Equipment Failure and Intelligent Operation and Maintenance Research

“…Yaw transmission issues include the following: a lack of lubricating oil or deterioration of the lubricating oil in the planetary gear train of yaw transmission; excessive content of mechanical impurities in the lubricating oil; transmission bearing damage; a lack of lubricating grease in the transmission; and yaw gear occlusion [68].…”

Review of control strategy of large horizontal‐axis wind turbines yaw system

“…As to x , it is directly connected with WT spacing and difficult to change after the establishment of wind farm. Therefore, scholars put forward the yaw control as shown in Figure 8B to improve U WT 2 57–59,62–65,73 . Through the active yaw of WT1, WT2 is exposed to more nature wind, and x is going to increase at the same time.…”

“…Therefore, scholars put forward the yaw control as shown in Figure 8B to improve U WT2 . [57][58][59][62][63][64][65]73 Through the active yaw of WT1, WT2 is exposed to more nature wind, and x is going to increase at the same time.…”

Stress Characteristics of Horizontal-Axis Wind Turbine Blades under Dynamic Yaw

“…The load on the wind turbine blades changes with azimuthal changes; the trailing and shed wake vortices increase indistinctly; and the wake velocity distribution is asymmetrical, according to aeroelasticity studies of wind turbines [8][9][10]. Numerous numerical techniques have been utilized to determine the effects of the yaw coefficient on wind turbines' power, power coefficients, and rotor torque.…”