Presenter: Arne Bartschat, Fraunhofer IWES, Hamburg

Inviting Professor: Prof. Dr.-Ing. Jan Wenske

Abstract:

Oscillating and grease-lubricated slewing bearings are used in several applications. One of the most demanding and challenging application is the rotor blade bearing of wind turbines. Blade bearings carry all combined loads transmitted by the rotor blades and enable the adjustment of the angle of attack of the inflow. This adjustment is called pitching, and it is a fundamental and safety relevant control feature of modern wind turbines. However, blade bearings are subject to premature failures due to different failure modes and recent research has been showing that failure rates for this component are increasing for modern and larger wind turbines. Wear is one of these challenging failure modes which can reduce the service life and affect functional safety. Besides bearing design and lubricant properties, the operating conditions and control strategies of wind turbines can influence the occurrence of wear in both negative and positive ways. The presentation gives insights into an ongoing PhD thesis and focuses on operating conditions and control mechanisms of modern wind turbines and their effect on surface initiated wear of blade bearing raceways. In addition, a model based methodology for assessing the site and controller related risk of wear during operation of the wind turbine and an on-demand protection run strategy for wear protection is presented.