Coffey
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This document summarizes a presentation on blade reliability from a wind turbine operator. It discusses the operator's fleet of over 3000 turbines across the US, and provides data on reported blade damage over 7 years. The top damage types - lightning, leading edge erosion, cracks and gel coat damage - account for 80% of reported issues. While 94% of damage is deemed repairable, damage to carbon spars and large structural cracks are less likely to be repaired. The presentation concludes with goals to improve data reporting, develop better lightning protection, and evaluate repair techniques for large cracks and carbon spars.
Coffey
- 1. Blade Reliability Case Study Sandia Wind Turbine Blade Workshop August 26, 2014 David Coffey
- 2. Overview • Snapshot of Iberdrola Renewables • Overview of blade failure data • Failure modes & repair rates • Examples of carbon spar damage • Examples of large crack repair • Conclusions • Improvement Goals Aug 26, 2014 David Coffey 2
- 3. 3 Iberdrola Renewables - North America Iberdrola Renewables develops, owns and operates wind plants throughout the U.S. • 3000+ turbines • 56 wind farms • 18 states • 6+ GW capacity • 6 different OEMs • Rotor dia. 47-102 m O & M Engineering: • Performance & Reliability • Continuous Improvement • Root cause analysis • Reliability centered maintenance • Failure rate projections • Repair specifications Aug 26, 2014 David Coffey
- 4. 4 Snapshot of Iberdrola Renewables Fleet Aug 26, 2014 David Coffey
- 5. Blade Reliability Aug 26, 2014 David Coffey 5 “Repair required” blade damages by year: • 7+ years • ~ 2600 reports • includes end of warranty inspections, FM, operations etc. Typical types of damage: • Lightning • Cracks • Impact damage • Surface/gel coat • LE erosion
- 6. Blade Reliability Aug 26, 2014 David Coffey 6 Top 5 damage types: 1. Lightning 2. LE Erosion - Light/medium/heavy 3. Cracks 4. Gel coat damage 5. “Undetermined” includes: • Lightning • Ice • Moisture intrusion Damages can be broken down further by location on blade Top 9 represent 80%
- 7. Blade Reliability Aug 26, 2014 David Coffey 7 • 94% reported damage is repairable • Repair rates for lightning have improved • Carbon spar damage is still problematic • Structural cracks are less likely to be repairable
- 8. Examples of carbon spar lightning damage Repairable today Repairable tomorrow? Aug 26, 2014 David Coffey 8
- 9. 9 Examples of large crack repair Aug 26, 2014 David Coffey Upper shell Lower shell • Testing feasibility of large crack repairs • Will the repairs last? • Is it economical?
- 10. Blade Reliability Conclusions: 1. Overall blade damage rates are higher than expected 2. Lightning damage, LE erosion, Gel coat damage account for 80% of damage reported 3. 94% total repair rate for all blade damages – 6% replacement rate drives cost of ownership 4. Ongoing cost of ownership for carbon spar blades is higher than other blade types – Actively seeking improved protection and repair options. Aug 26, 2014 David Coffey 10
- 11. Improvement Goals: 1. Blade damage – Improved data reporting – standard method of damage categorization – Continue to refine and improve damage reporting data base • Clear and consistent criteria for run vs. stop decisions • Clarify repair criteria – Up tower repair – types and severity – Ground repair – economic feasibility of repairs 2. Lightning protection: – Design and test standards • Improvements needed to IEC61400-24 lightning protection efficiency calculations – LPS system enhancements 3. Large crack repair 4. Carbon spar repair Aug 26, 2014 David Coffey 11
- 12. Thank You! David Coffey 12