Yaw Misalignment Detection, Correction and verification of result.
What is Yaw Misalignment?
Wind turbines operate at their maximal potential power generation when the rotor is facing directly into the free incoming wind.
The wind direction measurement instrument, situated on the nacelle behind the rotor, is used to control the optimal position of the rotor to harvest the maximal energy from the wind.
However, due to the turbulence in front of the rotor (rotor blocking effect), the shape of the nacelle, the turbulence generated while the wind is passing the rotor, or the calibration errors at installation, the wind direction measurement instrument cannot measure correctly from which angle the wind is hitting the rotor. In addition, the precision of the wind direction measurement instrument will be reduced over time.
When the rotor is not facing directly into the wind, this is referred to as “Yaw Misalignment”.
Why does that matter?
A wind turbine that is misaligned with the free incoming wind will incur a loss of performance and, consequently, a reduction in revenue. For example, an average yaw misalignment of 6.20 (measurements observed on 12 different wind turbines) will result in 2% annual energy production loss (Source: Avent Lidar Technology).
During its lifecycle, a wind turbine is submitted to a complex system of dynamic and aerodynamic conditions. A turbine with yaw misalignment will be prone to vibrations causing excessive stress and fatigue, leading to main component failures, costly downtime and reduced life expectancy. For example, on a turbine operating with 150 average yaw misalignment, the expected blade lifetime is reduced from 20 years to 8 years (Source: DNV-GL).
We use nacelle-based LiDAR technology to detect and correct yaw misalignment followed by a verification of the correction documented in a report to the owner. The result is perceived by an increased annual energy production, reduced loads.
Please watch the video illustrating Yaw Misalignment Detection and Correction: