A variety of ideas were generated by the working groups along with new questions raised, with several themes emerging. One challenge highlighted is the certification of WTs using LAC for extreme load reduction. Because 100% lidar availability is unlikely, ensuring that either the lidar is functioning properly or the turbine is operating in a “safe mode” when extreme wind conditions occur is critical. Another topic addressed is how to reconcile site-specific lidar properties affecting LAC with more general WT type certification. Wind turbines are type certified for a specific wind class, but lidar availability, with implications for controller performance, depends on additional atmospheric conditions. Further themes addressed include the need for clarity in modeling lidar preview measurements in the extreme wind fields used for certain design load cases, as well as procedures for verifying the performance of the lidar and lidar-assisted controller during prototype testing. Lastly, one overarching point that was raised is that guidelines for certification of WTs with LAC should remain as general as possible and only address areas where LAC presents unique challenges not covered by existing design standards.
The ideas formulated during the workshop are being incorporated by some of the workshop participants into a document “Best Practices for Certification of Lidar-Assisted Control Applications,” which will be made available on the Task 32 website when complete. The content of this Task 32 document will be used by DNV GL as they create their guidelines on certifying WTs with LAC, planned for later in 2018.