INTRODUCTION TO LEADING EDGE REPAIR AND PROTECTION
Wind turbine leading edge protection has been one of the most talked about topics when it comes to wind turbine maintenance. The leading edge is responsible for the blade’s aerodynamic efficiency and power output. For this reason, the leading edge protection (LEP) gets the most attention nowadays.
In one of our previous posts “Maintaining Renewable Energy”, we touch upon the maintenance issues encountered in the wind power turbine as a whole, and the solutions Belzona offers for the repair and protection of each part of the turbine. In this post, our focus is the leading edge protection.
What is a leading edge?
The leading edge of a blade is the foremost edge of the airfoil or the part of the blade that first contacts air.
Leading Edge Wear and Tear
Cause of the leading edge damage can vary based on the terrain a wind farm is located in. Typically, leading edge defects can be caused by wet (rain, sleet, hail, snow) and/or dry (dust, abrasive air, bugs) atmospheric and environmental particulates. Lightning strikes and surface icing are two other atmospheric phenomena that might cause tear and, in some extreme cases, even rupture in the blade. The life expectancy of an unprotected leading edge at the manufacturer’s facility can be significantly decreased. According to www.windsystemsmag.com, eroded leading edges will reduce the aerodynamic efficiency of the blades, and many sites have measured decreased power production by as much as 12%.
Leading Edge Protection
In recent years, more blade manufacturers have started offering various type of LEP including tapes and protective coatings. However, that is not the global trend. Many wind farms currently in operation face the challenge of protecting the damaged blades and keeping the turbines running and producing energy.
The solutions offered by Belzona are suitable to be applied on new build equipment as a preventative measure, as well as to repair and protect damaged equipment already in operation. In this post, we demonstrate the repair of a blade that had been damaged in service.
Leading Edge Protection Drawing
In this video, we demonstrate how to repair a leading edge and how to protect it from future environmental impact. The edge of this blade had been weathered down and first required to be rebuilt to the original profile. Once the edge was restored, a protective coating was applied.
For this repair, we used Belzona 1121 (Super XL-Metal), Belzona 1341 (Supermetalglide), Belzona 9111 (Cleaner/Degreaser), pre-formed molds, and a few tools from our machine shop. We started the application by preparing the surface. Using a handheld sander, we removed the existing coating and all loose particles. With an MBX bristle blaster we prepared the surface profile for optimal adhesion of the repair composite. Belzona 1121 was then mixed according to the Instructions for Use and applied onto the repair area with a brush. The mixed material was well embedded into the surface to ensure good adhesion. Pre-formed molds of different sizes were used to remove excess product and to smooth out the surface, following the natural curvature of the blade. Once the composite material became stable, Belzona 1341 was brush applied as a protective top coating.