Development of Nacelle-Lidar-Based Methods for Performance Verification and Yield Improvement of Wind Farms in Complex Terrain

For wind turbines operating in complex terrain, actual wind conditions can differ significantly from those assumed during the planning phase. This can lead to differences between predicted and actual energy yields. Subsequent verification of the power curve can help identify the causes of such deviations and derive suitable measures to improve turbine operation. However, conventional measurement methods, particularly in complex terrain, require extensive site calibrations using meteorological masts and are therefore time-consuming and costly.

The ELISE project therefore develops new methods that enable commercial nacelle-mounted lidar systems to be used for power curve verification in complex terrain. The lidar systems measure the incoming wind at different distances upstream of the rotor. Model-based methods are used to determine the undisturbed wind conditions from these measurements and to derive the wind conditions required for power curve measurements. Particular emphasis is placed on accounting for the induction zone upstream of the rotor and on quantifying measurement and modeling uncertainties.

In addition, further methods are being developed to determine additional wind parameters from nacelle-lidar measurements. The focus is on turbulence intensity as well as wind shear and wind veer. Physical and spectral models are used to correct lidar measurements, quantify their uncertainties, and enable the methods to be applied under different flow conditions in complex terrain.

The developed methods are investigated and validated using existing measurement data and flow simulations and subsequently tested on real wind turbines. In the long term, the results are intended to help establish nacelle-lidar-based power curve measurements in complex terrain as a more cost-effective alternative to extensive meteorological mast campaigns and to contribute to the further development of relevant IEC standards.
 

Preceding project

Adaptive operating strategies for existing wind turbines