Wind Turbine Pitch Bearing Reliability, Maintenance and Life Extension

Wind turbine pitch bearing early failures are common in some of the newer and larger 2X-6X wind turbines during the initial five years of operation. Most of these failures are due to the pitch bearing design related issues. Bearing suppliers are required to produce large volumes under demanding cost constraints. Also, working on improving the design and quality and offering various upgrades at the same time can be challenging. Operators need to know the impact of these issues on their fleet reliability and return of investment before turbine installations. Typically, pitch bearing failure assessments and root cause analysis are not done in detail to conduct reliability analysis and track the reasons for failure. In addition to the specific pitch bearing design issues, neighboring systems (blades and hub) design and reliability, and turbine operating conditions and maintenance have a significant impact on pitch bearing life. These pitch-related issues are summarized in this report focusing on turbine pitch technology evolutions, impact on reliability and providing recommendations to owners/operators to extend pitch service life to reduce operations and maintenance (O&M) costs.