Pitch bearing case study with supervisory control data of 7MW wind turbine

Abstract

Pitch bearings of wind turbines are subjected to high bending moments whilst oscillating at low speed and small amplitude. Individual pitch control is becoming a common technology of modern large capacity wind turbines to capture more energy from wind and reduce loads on turbine structures. However, this new technology is likely to result in more frequent small amplitude oscillations of the pitch bearing, and industry forecast this harsh operating condition may accelerate oscillation wear damage while still considering the rolling contact fatigue damage as one of the basic failure modes. A case study on the pitch bearing performance was conducted using the latest methods suggested by industry. The study uses time-series data to consider detailed pitch motion and load profile in the evaluation process. The data from the Supervisory Control and Data Acquisition of a 7MW Levenmouth Demonstration Turbine was applied to the entire process for demonstrating its practical application and suggesting other potential uses such as pitch bearing test strategy enhancement or pitch bearing health and usage monitoring with actual turbine operating data.