HAZARDS AND SOLUTIONS OF PIN HOLES IN SURFACE OF WIND TURBINE BLADES 1

With the rapid development of the wind energy industry, more and more wind turbine blade factories, main engine factories and even wind fields gradually increase their requirements in appearance and performance of wind turbine blades. To eliminate the negative impact of pin holes in surface is one of the basic requirements.
In the manufacturing process of wind turbine blades, surfaces of wind turbine blades may inevitably have some pin holes. These pin holes are not given due attention, and it's usually reckoned that, they affect appearance, and damage mechanical properties of wind turbine blade to some extent, but the whole service life is not significantly affected. In fact, pin holes will not only be detrimental to appearance of wind turbine blade but also reduce the strength and greatly increase the probability of wind turbine blade struck by lightning. In our research on some wind fields in Inner Mongolia, Hubei, Jiangsu and Guangdong, many maintenance personnel introduced that old wind turbine blade which has been used for over one year is more susceptible to lightning than new one. It's found while sampling lightning struck debris that most of wind turbine blades struck by lightning have sand holes or coating is cracked as a whole.
In the thunderstorm weather, rainwater may penetrate into inner cavity of wind turbine blade from these gaps, and this part of rainwater will be instantly gasified after lightning stroke, causing cavity pressure to suddenly soar and getting wind turbine blade ruptured. It's found after carefully observation the fracture of wind turbine blade that, there is not a trace of burning, but tear-shaped. This also holds true for the inference above.