Wind Blade Failure Identification and Prevention

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2 Wind Blade Failure Identification and Prevention Gary Kanaby Director of Sales/Wind Energy MFG Wind Molded Fiber Glass Companies January 29-31, 2013 Orange County Convention Center, Orlando, Fla.

3 Cradle to Grave Composite Capability for Wind Energy Four factories fabricating components for wind energy Composite Component Manufacturing for OEM s Field Repairs and Maintenance Services Field O&M services for wind farm operators After-market and warranty work Factory Repairs and Reconditioning of Components Engineering & Research Lab Spare and Replacement Parts for Legacy Equipment Two facilities open to factory repairs Reverse engineering and custom tooling 3

4 Presentation Outline Prevention of blade problems begins in Design Carried out in Manufacturing And continues through O & M Size has challenged blade building. Typical blade design and fabrication methods. Blade building challenges. Factory Inspection techniques. On site inspection at delivery and installation. End of Warranty inspection. Regular scheduled maintenance. Blade issues in the field. Repair procedures are carefully pre-planned and managed.

5 Design Considerations Design for manufacturability. Include up to date technology. Advanced materials. Lightning protection systems. Protective coatings (and ice shedding) Lessons learned from past failures. Rigorous testing. Designed for proper wind regime. Ample design margins. Wind Technology Testing Center (Boston)

6 30 Years of Blade Scaling 170 kgs 10,000 kgs.

7 75m Blade Source: Siemens Source: Euros

8 Typical Blade Construction

9 Fiber Placement tons of glass placed in mold with proper positioning within ½ shift. Errors in positioning could result in blade failure. Source: Siemens

10 Infusion Movement in the glass as vacuum is applied or Non infused areas are problems to avoid. Source MFG South Dakota

11 Mold Closing 150 meters or more of controlled bond line. Source: LM Glasfiber

12 Robotic Cutting & Drilling Blade facing and hole positioning within thousands of an inch. Source MFG South Dakota

13 Robotic Paint Booth Coatings need to last 20+ years. Source MFG South Dakota

14 Incomplete Infusion Thermographic imaging can be used to find dry spots in the laminate or voids in the core bonding.

15 Movement during vacuum Wrinkles in fabric a big concern. Ultrasound scanning

16 Barriers to Entry and Competing in the Market Huge capital investment. Warranty risk. Absence of long term contracts. Uncertainty of the market due to short extensions of tax incentives and lack of a long term energy policy. Unfair advantage from foreign suppliers.

17 Onsite Inspections and Repairs New site delivery and construction End of warranty Last chance for warranty claim. First chance to find lighting or other damage. Documentation of blade condition-start of data-base. Periodic Scheduled Blades should be re-inspected & repaired periodically. After an event. Sampling or turbines that have had strikes previously. Protection for LE after repairs. Lightning Protection System (LPS) verification.

18 New site Transportation and Installation Damage First chance for outside inspector to examine the blades. Defects are taken care of while blades are on the ground and least costly. If defects are not corrected, a small problem can lead to a future failure.

19 Ground Inspections Inspections from the ground save time and money. If defects are found uptower inspections can verify damage. 400mm lens from ground

20 Uptower Inspections/Repairs Using suspended work platforms, technicians access the blades up tower.

21 Inspect at End of Warranty Verify condition at end of warranty with ISP. Report and database is created. Warranty repairs are completed before hand off. Non-warranty repairs can also be completed at the time of inspection. Suggest that both Dynamic Mass and Aero assessment is made (sampling) Assessment inexpensive Corrections are more costly

22 Benefits of Scheduled Maintenance Increased availability. Reduce/eliminate catastrophic failures. Reduce/eliminate large repairs. Reduced crane/mobilization cost. Increased aerodynamic efficiency. Leading Edge Erosion Correct Pitch Angle

23 What is Scheduled Maintenance? Scheduled during non-productive season. Inspections from the ground. Inexpensive and easy. Use camera to document. Up-tower. Verification of damage. Repair are completed immediately. While up tower. Check LPS. Open drain hole. Protective LE coating.

24 Leading Edge Erosion LE erosion is most common blade aging issue. Monitor progress. Decide when to address it. Repairs Easily repaired up tower. LE shape can be verified with templates. While doing the repairs add protection. LEP Open drain hole Protective LE coating

25 Lightning Damage

26 Lightning System Testing Digital Low Resistance Ohmmeter Test each receptor

27 Lost Revenue Reduced energy as result of poor aerodynamics & pitch errors Blade vibrations damage gearbox. Reduced energy for shut down during icing & high winds. Lost revenue due to turbine non-operation while waiting for repairs to be completed. Access to the blade using crane/lift. Actual cost of the needed repair.

28 Rotor Imbalance Dynamic Rotor Balancing can detect and correct mass imbalance. Mass imbalance can cause excessive main bearing wear and gearbox problems. Moment varies due to uneven blade masses or distribution. Hub imbalance or flange errors Are the tips of the blades equidistant? Bent shaft. Blades have absorbed oil or water.

29 Aerodynamic Imbalance Blades are producing varying power. Uneven blade profiles. Built wrong Repairs Erosion Coning angle errors. Pitch angle varies from blade to blade.

30 Aero-Dynamic Blade Balancing

31 Condition Monitoring Active Condition Monitoring Smart blades send information to the controller If strains are too high, angle of attack can be adjusted. Detection of major degradation of laminate or bond can shutdown machine. Fiber- optic strain gauges run span wise. Shutdown and start up during icing is controlled, minimizing downtime. Sensors in root detect imbalance.

32 Service Challenges Safety. Qualification and Acceptance by wind farm own Training extensive. Managing from afar. Quality Control. Engineering support. Retention of technicians during slow season

33 Summary Blade failure prevention begins at the design Through factory inspections defects can be found and corrected-or the blade is rejected. Upon delivery third party inspections & repairs can find & remedy defects before operation. End of warranty reveals the blade s state after two years. Inspections throughout the life of the rotor will identify defects that can be addressed before they progress to catastrophic failure. A fully functional LPS will limit lightning damage. Rotor mass & aerodynamic balance can prevent premature failures.

34 The End Gary Kanaby Molded Fiber Glass Companies Wind Energy Services Company January 29-31, 2013 Orange County Convention Center, Orlando, Fla.