1. Leading edge corrosion
Corrosion of the leading edge causes changes in the airfoil. Due to the deformation of the airfoil, the energy captured by the blade will be reduced by more than 5%, and the damage of the leading edge is easy to repair in the early stage.

2. If the leading edge is cracked, if the leading edge of the blade is cracked, it should be repaired as soon as possible. If it is not repaired in time, the crack will become longer and longer, and under the action of air, the skin will peel off and crack. If the blade skin cracks less than 6 feet, it can still be repaired barely. If there is more cracking, the entire blade must be replaced. This means high material, maintenance costs and long-term power loss.

3. Damaged trailing edge
Damage to the trailing edge is easy to deal with in the early stages. If left unchecked and allowed to develop, minor damage to the trailing edge can cause major problems. As you can see in the photo below, the crack splits along the chord of the blade, leads straight to the beam, and then tears along the beam. This blade is near catastrophic failure.

4. Leaf root fracture
Leaf root fractures must be discovered as early as possible, because leaf root fractures often trigger catastrophic failure. The root crack of this blade in the photo has expanded and it is difficult to repair.

5. Surface cracks
Even small cracks and sand holes can cause water to penetrate into the composite material. In severe winter, the water will freeze and cause rapid damage to the inner core. Small cracks will spread and grow, eventually leading to blade failure.

6. Lightning damage
Damage to the lightning protection system will cause the blade to suffer lightning strikes. If the lightning guide is damaged or not working properly, the blades are easily hit and damaged when lightning strikes. There is already evidence that lightning will hit a certain unit in a wind farm many times, while other units in the wind farm are never struck by lightning. This is because there is a problem with the lightning guide of this unit. It is very important to repair the lightning protection system in time.