Blade Repair Challenges

Transcription

1 Blade Repair Challenges Wind Energy Operations & Maintenance Summit Wind Energy Update April 25-27, 2012 Dallas, TX Presented by Gary Kanaby

2 Quality Engineered Value 2

3 Presenta(on Outline Neglecting inspection and preventative maintenance is costly, so with a growing variety of blades now in service - some approaching the end of their warranty periods - discover how to avoid major rotor blade maintenance issues. Uncover the damage caused by bird strikes, lightning strikes, leading edge erosion, trailing edge damage, material fatigue, plus surface erosion from rain, hail, ice and insects and find out what measures you can take to avoid minimizing turbine productivity. Decide between a close visual inspection with report, blade cleaning, or a structural repair, and ensure repair procedures are carefully pre- planned and managed, with adequate back- up from other team members. 3

4 Preventa(ve Maintenance 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. LPS verification 4

5 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. Inspect at End of Warranty Suggest that both Dynamic Mass and Aero assessment are made (sampling) - Assessment inexpensive - Corrections are more costly

6 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

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

8 Aero- Dynamic Blade Balancing 8

9 Benefits of Scheduled Maintenance Increased availability. Reduce/eliminate large repairs and replacements. Reduced crane/mobiliza(on cost. Increased aerodynamic efficiency. Leading edge erosion Correct Pitch Angle

10 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 400mm lens from ground 10

11 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

12 Lightning Damage

13 Lightning System Tes(ng Digital Low Resistance Ohmmeter Test each receptor

14 Other Advanced Inspec(on Techniques Ultrasound Imaging Thermographic Imaging 14

15 Lost Revenue Reduced energy as result of poor aerodynamics & pitch errors Blade vibra(ons damage gearbox Reduced energy for shut down during icing & high winds Lost revenue due to turbine non- opera(on while wai(ng for repairs to be completed Access to the blade using crane/lip Actual cost of the needed repair

16 Objectives: For Exis(ng Wind Turbines... Increase productivity Increase availability Minimize downtime A Service Plan! Reduce/eliminate large repairs and replacements

17 Ac(ve Condi(on Monitoring Condi(on Monitoring Smart blades send informa(on to the controller If strains are too high, angle of avack can be adjusted Detec(on of major degrada(on of laminate or bond can shutdown machine - Fiber- op(c strain gauges run span wise Shutdown and start up during icing is controlled, minimizing down(me - Sensors in root detect imbalance

18 Summary The cost of the repair itself is a small frac(on of the total revenue lost due to blade problems. Total cost must include loss of energy produc(on, damage to other components plus increased mobiliza(on and repair costs. Scheduling maintenance increases produc(vity and decreases the total repair costs. A number of useful tools are available to inspect and monitor blades in the field.

19 Wind Energy Services Company Gary Kanaby In the old days climbing a US Windpower 100 kw turbine