Optimization of critical Blade Bearings
The blade bearings are safety-relevant components of a wind turbine: if they can no longer withstand the loads, the turbine can lose a blade. When this worst-case scenario occurred in December 2018 on a wind turbine in the wind farm Gau-Bickelheim, all turbines in the farm had to be stopped at short notice. GfW reacted quickly and commissioned eolotec to optimize the blade bearings. The aim was to be able to put the turbines back into operation as soon as possible, enabling safe and sustainable power generation.
The cause of the blade loss of the Kenersys turbine was a crack that develops on the outer ring of the blade bearing. The solution therefore involves stabilization by means of a stiffening ring. The intention is to reduce the deformation of the blade bearing during operation and thus the stresses occurring in the outer ring. The FE calculation carried out by eolotec was able to confirm that the stress maximum occurs in the bore holes. Presumably, scarring due to corrosion in the bore holes represents the starting point for cracks to the raceway surface. One measure was therefore to rework the corrosion protection at the critical points. For the blade bearing incl. stiffening ring Eolotec carried out the mathematical proof in accordance with certification requirements as part of the project. A comparison of the original bearing with the optimized variant confirmed that the stresses at the critical points had been reduced: It was possible to reduce the stresses by 25-30%. Next to the preparation of the manufacturing documents, eolotec supported the establishment of the supply chain as well as the procurement of necessary equipment for the installation of the bearing upgrade.
Together with GFW, the operators & owners of the turbines were offered a timely as well as economical solution to the problem: "All in all the project was very successful. Together with eolotec we were able to reach great resonance and received very positive feedback from operators and experts. We will certainly work together again", Jürgen Fuhrländer, Managing Director of GFW, concludes.
In the meantime, more than 20 plants have already been equipped with the optimized blade bearing system. In order to monitor the bearings a BBG sensor system is installed on each wind turbine.