This paper discusses the maintenance scheme for lightning damage to wind turbine blades. The types and characteristics of lightning damage are introduced, and the nondestructive testing methods of wind turbine blades are discussed. Through the comprehensive application of nondestructive testing methods and combined with repair technology, the reliability and service life of wind turbine blades can be effectively improved. This study proposes a repair technology for lightning damage to wind turbine blades, including repair process flow, repair material selection and performance requirements, and repair coating technology. Finally, through repair practice, the effectiveness and feasibility of this maintenance scheme are verified.
With the continuous improvement of global economic and environmental awareness, wind power generation has become one of the most popular and most promising clean energy sources. However, during the operation of the wind turbine, due to the installation position and elevation of the wind turbine, under different environmental conditions, lightning strikes are often encountered, resulting in damage to the wind turbine blades. The wind turbine blades are the core components of the wind turbine, and their damage will inevitably reduce the overall efficiency and life of the wind turbine, and even have a serious impact on the performance and safety of the wind turbine. Therefore, the problem of lightning damage repair of wind turbine blades has become an inevitable problem in the operation of the wind turbine.
1 Detection of lightning damage to wind turbine blades
1.1 Types and characteristics of lightning damage
As an important component of wind turbines, wind turbine blades are often affected by various environmental factors, among which lightning damage is a common form of damage. Lightning damage is divided into two forms: surface damage and deep damage. Common surface damage includes burns, pitting, wear, etc., while deep damage includes punching, tearing, cracks, etc. The characteristic of lightning damage to wind turbine blades is that the damaged area shows devastating damage, which may cause the blade to fail.
In the detection of lightning damage to wind turbine blades, non-destructive testing is a very important method. Non-destructive testing methods include contact and non-contact. Among them, contact non-destructive testing methods include ultrasonic testing, magnetic particle testing, penetration testing, etc.; non-contact non-destructive testing methods include infrared testing, laser testing, etc. Through non-destructive testing methods, the specific location and severity of lightning damage can be located, thereby providing a basis for repair.
Analysis and evaluation of test results are an indispensable part of lightning damage detection for wind turbine blades. By evaluating the degree of damage, a more detailed basis can be provided for repair and which repair plan is more appropriate can be determined. For wind turbine blades with less surface damage, chemical rust removal, polishing and other methods can be used for repair. For blades with deep damage, partial or complete replacement is required.
Detection and repair of lightning damage to wind turbine blades is the key to ensuring the safe operation and life extension of wind turbines. Through scientific and rigorous non-destructive testing and refined repair plans, the damage to wind turbine blades can be reduced and its long-term safe operation can be ensured.
1.2 Non-destructive testing methods for wind turbine blades
Non-destructive testing of wind turbine blades is a special testing technology developed for lightning damage to wind turbine blades. Its purpose is to discover possible hidden dangers in wind turbine blades so as to take timely and effective measures to repair them and improve the service life and safety of wind turbine blades.
In terms of non-destructive testing methods for wind turbine blades, there are currently many technologies such as magnetic particle method, ultrasonic method, infrared detection method, etc. Among them, the ultrasonic method is a method that is widely used and has good detection effect. It introduces ultrasonic waves into the wind turbine blades, and uses the reflection and scattering phenomena generated when sound waves propagate in different media to detect defects inside the wind turbine blades, and can conduct preliminary analysis and evaluation of different types of lightning damage.
For the analysis and evaluation of the detection results of the ultrasonic method, imaging technology can be used for further analysis. That is, by converting the detection results into pictures or videos, defects on the wind turbine blades can be visually discovered and located, and then maintenance and repair operations can be performed.
In short, non-destructive testing of wind turbine blades is a very important technology that can provide important guarantees for the sustainable development and safe production of the wind power industry. In recent years, related technologies have developed significantly, and various new non-destructive testing technologies have also emerged, which will undoubtedly benefit the further development of the wind power industry.
1.3 Analysis and evaluation of test results
During the use of wind turbines, the detection of lightning damage to blades is crucial. Through research, the types and characteristics of lightning damage to blades are understood, and a variety of non-destructive testing methods are used in combination for analysis and evaluation. In specific operations, infrared thermal imaging technology is used to detect blade surface temperature, laser interference technology is used to detect blade deformation, and ultrasonic testing technology is used to detect internal defects of blades. According to the test results, the extent and location of the blade lightning damage are further analyzed. During the test and evaluation process, it was found that if the tiny defects on the blades are not repaired in time, they will gradually expand under the action of the long-term wind field, eventually leading to the damage or even failure of the blades.
Therefore, based on the test and evaluation, a repair scheme is proposed, including process flow, material selection and performance requirements, and repair coating technology. We selected epoxy resin to fill the defects of the blades, and then applied conductive coating to restore its original conductive properties, so as to achieve the purpose of repairing lightning damage.
In addition, this paper carried out repair practice to further verify the feasibility and effectiveness of the repair scheme. The practical results show that the repaired blades can maintain good conductive properties and mechanical strength when used under multiple wind speeds and working conditions. This provides strong support for practical engineering applications.
In summary, the use of a variety of non-destructive testing methods combined with repair technology can effectively improve the reliability and service life of wind turbine blades.
2 Wind turbine blade lightning damage repair technology
2.1 Repair process flow
First, clean the damaged parts, including rust removal, cleaning, oil removal, and decontamination, to ensure that the surface of the damaged parts is flat. Then, pretreatment is carried out, and targeted pretreatment schemes are adopted, including anodizing, chemical passivation, etc., to improve the surface properties of the damaged parts. Next, according to the specific situation, appropriate repair materials are used for filling, coating, and repair. During the filling process, it is necessary to master the selection and use of filling materials to ensure the density and strength of the filling materials. In terms of coating, it is necessary to master modern coating technology to ensure the wear resistance, corrosion resistance, climate change resistance and other properties of the coating. Finally, inspection and testing are carried out to evaluate the repair effect to ensure that the repair quality meets the requirements and achieves the expected effect. Throughout the repair process, attention should be paid to details, and relevant process standards and specifications should be strictly followed to ensure the quality and safety of maintenance.
2.2 Repair material selection and performance requirements
In the repair scheme for lightning damage to wind turbine blades, the selection of repair materials and their performance requirements are very important links. First, the repair material must have good mechanical properties, such as high strength, high toughness and good fatigue performance, to ensure that the repaired blades can withstand long-term use and wind loads. Secondly, the repair material must have good weather resistance and corrosion resistance to adapt to the complex climate environment and harsh climatic conditions in the wind farm.
When selecting repair materials, their processability and operability also need to be considered. Excellent repair materials should have good repair adaptability, including easy coating, infusion and construction, and be able to meet the needs of specific applications. In addition, the repair material should have appropriate adhesion and good wear resistance so that it will not loosen or fall off during long-term use.
Currently, commonly used repair materials include fiberglass, carbon fiber, composite materials, epoxy resin, etc. These materials have good mechanical properties and corrosion resistance, and are easy to process and operate. At the same time, some new composite materials, such as carbon fiber reinforced epoxy resin (CFRP) and glass fiber reinforced polypropylene (GFPP), show more excellent characteristics in strength and toughness, so they can also be used as the preferred solution for repair materials.
In addition to material selection, it is also necessary to conduct corresponding tests and evaluations on the repair materials. Through experiments, the performance and adaptability of the repair materials can be evaluated, and corresponding improvement opinions and suggestions can be put forward. Therefore, for the repair plan of wind turbine blade lightning damage, the selection of repair materials and performance requirements are crucial links, which need to be scientifically, systematically and deeply studied and explored.
2.3 Repair coating technology
In the repair process of wind turbine blade lightning damage, coating technology is a very critical step. The coating can not only play a protective role, but also improve the conductivity of the blade surface and reduce the possibility of lightning strike.
In terms of the selection of coating materials, first of all, they must have high electrical conductivity. The more commonly used coating materials include polymers containing silver or metal particles, carbon nanotubes, metal oxides, etc. Among them, the silver-containing polymer coating is an excellent option, which not only has good electrical conductivity, but also has good corrosion resistance.
When selecting coating materials, you also need to pay attention to the adhesion with the wind turbine blade substrate. Usually, the coating is applied after surface treatment to enhance the bonding between the coating and the substrate. For example, sandblasting, chemical oxidation and other methods can be used for surface treatment, and then coating can be applied.
In addition, during the coating construction process, attention should also be paid to the thickness and uniformity of the coating to ensure that the coating can fully cover the blade surface and can be evenly distributed. At the same time, the baking process of the coating is also very important, and the baking temperature and time need to be strictly controlled to ensure that the performance of the coating is optimized.
Coating technology plays a very important role in the repair of lightning damage to wind turbine blades. The selection of coating materials and the control of the construction process need to be very rigorous to ensure that the repaired blades can operate stably for a long time.
3 Repair practice of lightning damage to wind turbine blades
3.1 Case of lightning damage to wind turbine blades
The lightning-struck blade (about L37.67~38.70 m SS surface) has a delamination damage at the leading edge, with obvious perforation holes in the damaged area and signs of blackening around it. The shell at the lightning strike point has penetrating damage.
According to the degree of damage, gradient grinding, N+1 laying, and vacuum infusion are used for repair. The specific repair steps are as follows:
(1) Skin structure repair: Grinding staggered layers → Cutting and laying → Inner skin repair → Vacuum infusion of outer skin core material → Heating and curing → Putty and paint repair.
(2) Web structure repair: Make web prefabricated parts → Grinding staggered layers → Install prefabricated parts → Cutting and laying → Hand-laying → Heating and curing.
3.2 Repair of fan blade skin structure
See Figures 2 and 3 for the laying of large cloth for the inner and outer skins of fan blades.
3.3 Web plate structure repair
Repair ideas: Make web plate pre-bracket → Web plate window → Grind staggered layer → Web plate repair.
In terms of blade repair, the purpose and plan of the repair should be clarified first, and the basic requirements and processes should be determined. While considering the specific operation process of the repair, it is also necessary to formulate corresponding repair methods for different damaged parts. In the process of formulating the repair method, various potential interference factors and how to evaluate the repair results should also be considered.
In terms of the selection of repair methods, it is necessary to select appropriate methods and technologies according to the specific performance and requirements of the blade. For example, non-contact non-destructive testing methods and image processing technologies can be selected in blade damage surveys to enable more accurate detection and analysis of wind turbine blades. In the repair coating technology, different coating materials and coating processes need to be selected to meet different repair requirements and performance requirements.
In short, when the actual formulation of the wind turbine blade lightning damage repair plan is carried out, the selection of damage survey and repair methods will directly affect the accuracy of the repair results and the significance of the repair effect. Therefore, in the process of formulating the repair plan, various factors need to be scientifically and systematically analyzed and considered to ensure the accuracy and reliability of the repair results.
3.4 Repair results and analysis
Through the repair practice of wind turbine blade lightning damage, the feasibility and effectiveness of the wind turbine blade lightning damage repair plan were verified. The specific steps are as follows: First, non-destructive testing is performed on the damaged wind turbine blade to determine the degree and location of damage; second, according to the degree and location of damage, appropriate repair materials are selected and repaired through coating technology; finally, the repaired blades are re-non-destructively tested to evaluate the repair effect.
The results show that the repair effect of this repair plan is good, and the repaired blades can still maintain high working efficiency and service life after lightning damage. At the same time, through strict control of the materials and performance requirements of the repair coating, it is ensured that the repaired blades have good corrosion resistance and fatigue resistance.
Through this repair study, the feasibility and effectiveness of the wind turbine blade lightning damage repair plan were verified, providing a reliable reference for future blade damage repair.
Conclusion
Through the discussion of the wind turbine blade lightning damage repair plan, the currently commonly used wind turbine blade lightning damage detection and repair technology was deeply studied and practiced. In terms of wind turbine blade lightning damage detection, the selection of nondestructive testing methods for different types and characteristics of damage and the analysis of test results can help improve the ability to identify and judge wind turbine blade lightning damage. In terms of wind turbine blade lightning damage repair technology, detailed repair process flow and repair material selection, performance requirements, and introduction of repair coating technology are expected to improve the repair effect of wind turbine blade lightning damage. At the same time, through the study of repair practice, the feasibility and actual effect of the wind turbine blade lightning damage repair plan were explored, and the repair results were analyzed and evaluated in detail. The research conclusions of this paper have certain reference value for the formulation and implementation of wind turbine blade lightning damage repair plans.
