Wind Composite Services Group Blade Repair Service Guidance 01/06/2019 Wind Composite Services Group Blade Repair Service Guidance 20 May, 2015

Wind Composite Services Owned by Tecsis, 2nd largest wind blade producer globally. Servicing blades since 2007. Data base of ___________inspected and repaired blades. Three types of work platforms available for up tower repairs. Engineers on hand to backup service teams. QC of every repair before departure from site.

Safety First

Approach to Blade Repairs

Non-Structural Repairs Non-Structural damage does not affect the blade’s sparcap or bonds. Sparcap

Non-Structural Repairs

Leading Edge Erosion

Further Neglect Can Result in Worse Damage

Lightning Damage Neglecting lightning damage can lead to serious problems Lightning Protection System (LPS) may be compromised.

Lightning Damage

Questions for the ISP Do you have written work instructions for this repair? Are the materials either the same or similar to the OEM’s? What resin system are you using? Epoxy or Polyester? Is it compatible? What is the fairing compound? Bondo, epoxy or Polyurethane? What paint are you using? While up-tower can you check the LPS? Drain hole?

Structural Damage Can the blade be repaired successfully? If so can it be done up tower, downtower or shipped to a factory? Is the repair worth the money? Worth the risk? Are there other alternatives? Do you or your ISP have the knowledge to make a good decision?

A Few Examples of Structural Damage Interior cracks Core debonded

Decision to repair up tower may be easy in some cases. But again ask questions

Questions to Ask Yourself Do we know the Root Cause of the damage? Did we address the root cause to prevent further damage after repairs? Do we have enough information to make a good decision as whether to repair or replace? Did we do a risk analysis?

Challenge the ISP Do they have written work Instructions? If so, on what are they based? Does the ISP have an in house composite engineer? Analytical tools? Do they have experience in this repair? Price cap? Warranty? Is the access method appropriate for the repairs?

Root Cause Analysis Identify key contributors to the blade damage Underestimated design loads Malfunctioning of control and safety systems Abnormal environmental conditions Manufacturing defects Design related issues

Structural Analysis and Validation Perform structural analysis based on operating conditions. Simulate and validate structural response to field test data.

Do we have photos such as these? Or the capabilities?

Engineered Repairs Based on results obtained, a detailed repair solution is prescribed. Optimized laminate schedule is determined based on structural analysis Repairs are validated during repairs Documentation of the work is retained

Summary Know what questions to ask Make decisions based on facts, data and financial sense Don’t be afraid to go to outside help Engineered solutions lead to longer asset life Lead to overall savings in O&M costs