An international paint coatings manufacturer, in collaboration with a wind energy technology developer, has developed a new polymer coating for wind turbine blades that protects them from lightning.
Like other high-rise objects, wind turbines are easy targets for lightning. The difficulty is that during thunderstorms, streamers originate from lightning rods or other metal pieces inside the blade. These often transform into leaders that connect with downward leaders from clouds, causing lightning strikes and significant damage to the blades. This results in breakage, weakening of the outer shell, and even loss of blades.
According to the manufacturer of the coating, during lightning activity around a wind turbine there is competition between streamers formed inside the blade and streamers formed at the lightning protection system on its outer surface.
The authors of the development claim that the coating applied to turbine blades near lLPSs increases the electric field in the air nearby to the coating, enabling the formation of a stronger leader from the lightning protection system. This increases the probability of lightning striking the lightning protection system instead of damaging the blade. Thus, the lightning current flows through the current collector without endangering the structural integrity.
The coating works by locally amplifying the electric field directly above the blade surface. Surface areas with increased electric field intensity are the first to exceed the air ionization threshold, creating corona zones along the blade's outer surface. As the electric field strength grows, these corona zones merge to generate a surface discharge and streamer that travels away from the blade. This reduces the field strength around the other conductors inside the blade. Thus, streamers on the blade's outer surface "win the race" to connect with downward leaders in the clouds.
The coating developed consists of a proprietary formula of conductive elements combined with a polyurethane paint.
We do not dare to rate the effectiveness of the idea, but we acknowledge that such a way of protection is appealing.
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