the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 02 Jul 2024
Repair of wind turbine blades: Experience and observations from India – A Review
Abstract. A large expansion of wind energy is planned in India. On the other side, older wind turbines are approaching the end of their lifetime in some cases. Improvement and quality of maintenance technologies of wind turbines are therefore very important for the successful expansion and support of wind energy generation in India. In this paper, the strategies, main challenges and procedures of wind turbine blade repair in India are summarized. The influence of location and climate, methods of damage identification and evaluation of the severity of blade damage, as well as steps involved in leading-edge erosion, laminate, foam, web, and serration damage repair are presented. This overview of the current situation, methods, and technologies should provide the basis for the optimization of repair technologies, development of new techniques and thus to the improvement of the reliability of wind energy generation in India.
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CC1: 'Comment on wes-2024-55', Christopher Harrison, 11 Jul 2024
The paper is slightly interesting, although it contains a lot of information which is common knowledge. Please consider: In Figure 1, which describes root causes for damage, the legend states one root cause as 'damage due to splitting of layers'. Splitting of layers, more commonly known as delamination, is of course a type of damage, not a root cause. One also states 'damage due to dust'. I do know know how dust causes damage to a fully cured laminate. Perhaps you can expand on that?
Also, later in Section 5 you describe the use of a pendulum. Can you please expand on its use?
Feel free to contact us if you need some advice.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC1 -
AC1: 'Reply on CC1', Refugine Nirmal Ignacy Muthu, 15 Jul 2024
This paper primarily focus on practical experience, and observations made by wind turbine service teams
- Delamination: Delamination, often resulting from various factors, may not initially cause severe issues. However, over time, it can grow and lead to significant problems. Although it is a type of damage, its progression can severely impact the structural integrity and performance of the laminate.
- Dust: Dust itself does not typically cause damage to a fully cured laminate. However, the question was framed to ask about the dust/sandstorms that occur in regions like Rajasthan in India, which could create severe damage to the blades.
- Pendulum Use in Section 5: The pendulum is used to check the orientation of the blade before and after repair. It is placed once the blade is set in its final position for repair. Throughout the repair or curing stages, the pendulum's position should remain unaltered to ensure accurate monitoring of the blade's orientation.
Citation: https://doi.org/10.5194/wes-2024-55-AC1 -
CC2: 'Reply on AC1', Christopher Harrison, 15 Jul 2024
Thanks for replying.
Of course the main issue in trying to understand the root cause of observed damage by using surveys of repair operatives, is that the repair operatives typically don't know what the root cause is! That is why you incorrectly describe an intermediate damage state (delamination) as a root cause. I suggest you update the paper to explain more clearly your reasoning.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC2
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AC1: 'Reply on CC1', Refugine Nirmal Ignacy Muthu, 15 Jul 2024
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RC1: 'Comment on wes-2024-55', Anonymous Referee #1, 15 Jul 2024
Dear authors,
while you are acknowledged to have collected a nice amount of practical data, the manuscript in the current version is a nice technical report, but not a scientific paper. To be of archival value, a study must be novel and deliver a message to the scientific community that could be of general and long-lasting validity. Most of the information in the paper is well-known in the field, while very site-specific data is of scarce interest for a large audience.
I would suggest re-thinking the study as technical report or re-elaborate the results in a more innovative way.
Citation: https://doi.org/10.5194/wes-2024-55-RC1 -
CC3: 'Comment on wes-2024-55', Leon Mishnaevsky, 15 Jul 2024
Dear Christoffer, dear Anonymous, thank you for your comments. While "The paper is slightly interesting, although it contains a lot of information which is common knowledge" (Christoffer) and "you are acknowledged to have collected a nice amount of practical data... [but] a study must be novel and deliver a message to the scientific community that could be of general and long-lasting validity". First, one person's common knowledge is another person's new and interesting facts. For me, it was new and potentially useful information, how Indian companies carry out blade repair (in our previous study, "Failure mechanisms of wind turbine blades in India: Climatic, regional and seasonal variability", Wind Energy, Vol. 25, 5, 2022, pp. 968-979, we observed that both damage mechanisms and repair results can be different in Europe and in India ). On whether an archival paper should necessarily contain a new theory of universe, and change scientific paradigm - in principle, it is always good to have papers, which "deliver a message to the scientific community that could be of general and long-lasting validity". But here, we collected interesting observations, which (in combination with data on Indian climatic conditions and Indian blade damage statistics) can be useful to optimize Indian maintenance approaches. P.S. Of course, "splitting of layers" is delamination. We used the words as they were said by repair technicians.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC3 -
RC2: 'Comment on wes-2024-55', Anonymous Referee #2, 18 Jul 2024
The authors conducted a review of the major sources of damage to wind turbines in India, along with current maintenance and repair practices. While the reviewer finds the topic and the research activity interesting and worthy of investigation, the study primarily reiterates common knowledge in the field rather than providing the novel insights typically expected from a review paper. Although the original content on O&M (Operations and Maintenance) experiences in India holds value, it lacks sufficient elaboration to contribute new knowledge. Additionally, the paper's presentation, particularly the graphical elements, needs significant improvement. Therefore, a revised submission of the research is recommended.
Citation: https://doi.org/10.5194/wes-2024-55-RC2 -
RC3: 'Comment on wes-2024-55', Anonymous Referee #3, 26 Sep 2024
I do not see any novelty or innovation in this manuscript that would justify publication. There are two main reasons for this assessment: the survey data does not provide useful statistical data and the discussion of repair techniques covers only ones that already well-known.
The total description of the two surveys is contained in the first paragraph of Section 2 and is badly deficient. There is no information about the geographical distribution of the survey responses or anything else that would indicate the level of representation. The responses are later broken down into the various states with no indication of how many turbines there are in these states and what fraction of them is covered by the survey. The time window of the survey is not given and the breakdown of the types of failure in Figure 2 into 4-month blocks of the year is not justified and poorly discussed. For example, the wind farms I am familiar with routinely undertake blade inspection in summer when the average wind speeds are lower, and so this time period is likely to show the largest number of blade failures but this fact has no meaning. Blade failure in general, can accumulate over periods of years, so the month of its discovery is unlikely to be significant. An exception is possibly lightning damage which can be maximised at certain months of the year and can occur quickly. Lightning strike rates vary significantly over India, Chakraborty et al. (2021, extra reference below) but no attempt is made to relate this to the blade failure data.
The lack of novel information is reflected in the pedestrian style of the writing. Section 3.2 starts with “Blades are one of the largest components in WT” which is one of the worst examples of meaningless statements but there are others. The use of pie charts unduly complicates the presentation: replacing figures 1- 4 with tables would shorten the manuscript and give the information in a more readable form. The lack of axis labels on figures 2 – 4 makes them even harder to read.
Additional Reference
Chakraborty, R., Chakraborty, A., Basha, G., & Ratnam, M. V. (2021). Lightning occurrences and intensity over the Indian region: long-term trends and future projections. Atmospheric Chemistry and Physics, 21(14), 11161-11177.
Citation: https://doi.org/10.5194/wes-2024-55-RC3
Status: closed
-
CC1: 'Comment on wes-2024-55', Christopher Harrison, 11 Jul 2024
The paper is slightly interesting, although it contains a lot of information which is common knowledge. Please consider: In Figure 1, which describes root causes for damage, the legend states one root cause as 'damage due to splitting of layers'. Splitting of layers, more commonly known as delamination, is of course a type of damage, not a root cause. One also states 'damage due to dust'. I do know know how dust causes damage to a fully cured laminate. Perhaps you can expand on that?
Also, later in Section 5 you describe the use of a pendulum. Can you please expand on its use?
Feel free to contact us if you need some advice.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC1 -
AC1: 'Reply on CC1', Refugine Nirmal Ignacy Muthu, 15 Jul 2024
This paper primarily focus on practical experience, and observations made by wind turbine service teams
- Delamination: Delamination, often resulting from various factors, may not initially cause severe issues. However, over time, it can grow and lead to significant problems. Although it is a type of damage, its progression can severely impact the structural integrity and performance of the laminate.
- Dust: Dust itself does not typically cause damage to a fully cured laminate. However, the question was framed to ask about the dust/sandstorms that occur in regions like Rajasthan in India, which could create severe damage to the blades.
- Pendulum Use in Section 5: The pendulum is used to check the orientation of the blade before and after repair. It is placed once the blade is set in its final position for repair. Throughout the repair or curing stages, the pendulum's position should remain unaltered to ensure accurate monitoring of the blade's orientation.
Citation: https://doi.org/10.5194/wes-2024-55-AC1 -
CC2: 'Reply on AC1', Christopher Harrison, 15 Jul 2024
Thanks for replying.
Of course the main issue in trying to understand the root cause of observed damage by using surveys of repair operatives, is that the repair operatives typically don't know what the root cause is! That is why you incorrectly describe an intermediate damage state (delamination) as a root cause. I suggest you update the paper to explain more clearly your reasoning.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC2
-
AC1: 'Reply on CC1', Refugine Nirmal Ignacy Muthu, 15 Jul 2024
-
RC1: 'Comment on wes-2024-55', Anonymous Referee #1, 15 Jul 2024
Dear authors,
while you are acknowledged to have collected a nice amount of practical data, the manuscript in the current version is a nice technical report, but not a scientific paper. To be of archival value, a study must be novel and deliver a message to the scientific community that could be of general and long-lasting validity. Most of the information in the paper is well-known in the field, while very site-specific data is of scarce interest for a large audience.
I would suggest re-thinking the study as technical report or re-elaborate the results in a more innovative way.
Citation: https://doi.org/10.5194/wes-2024-55-RC1 -
CC3: 'Comment on wes-2024-55', Leon Mishnaevsky, 15 Jul 2024
Dear Christoffer, dear Anonymous, thank you for your comments. While "The paper is slightly interesting, although it contains a lot of information which is common knowledge" (Christoffer) and "you are acknowledged to have collected a nice amount of practical data... [but] a study must be novel and deliver a message to the scientific community that could be of general and long-lasting validity". First, one person's common knowledge is another person's new and interesting facts. For me, it was new and potentially useful information, how Indian companies carry out blade repair (in our previous study, "Failure mechanisms of wind turbine blades in India: Climatic, regional and seasonal variability", Wind Energy, Vol. 25, 5, 2022, pp. 968-979, we observed that both damage mechanisms and repair results can be different in Europe and in India ). On whether an archival paper should necessarily contain a new theory of universe, and change scientific paradigm - in principle, it is always good to have papers, which "deliver a message to the scientific community that could be of general and long-lasting validity". But here, we collected interesting observations, which (in combination with data on Indian climatic conditions and Indian blade damage statistics) can be useful to optimize Indian maintenance approaches. P.S. Of course, "splitting of layers" is delamination. We used the words as they were said by repair technicians.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2024-55-CC3 -
RC2: 'Comment on wes-2024-55', Anonymous Referee #2, 18 Jul 2024
The authors conducted a review of the major sources of damage to wind turbines in India, along with current maintenance and repair practices. While the reviewer finds the topic and the research activity interesting and worthy of investigation, the study primarily reiterates common knowledge in the field rather than providing the novel insights typically expected from a review paper. Although the original content on O&M (Operations and Maintenance) experiences in India holds value, it lacks sufficient elaboration to contribute new knowledge. Additionally, the paper's presentation, particularly the graphical elements, needs significant improvement. Therefore, a revised submission of the research is recommended.
Citation: https://doi.org/10.5194/wes-2024-55-RC2 -
RC3: 'Comment on wes-2024-55', Anonymous Referee #3, 26 Sep 2024
I do not see any novelty or innovation in this manuscript that would justify publication. There are two main reasons for this assessment: the survey data does not provide useful statistical data and the discussion of repair techniques covers only ones that already well-known.
The total description of the two surveys is contained in the first paragraph of Section 2 and is badly deficient. There is no information about the geographical distribution of the survey responses or anything else that would indicate the level of representation. The responses are later broken down into the various states with no indication of how many turbines there are in these states and what fraction of them is covered by the survey. The time window of the survey is not given and the breakdown of the types of failure in Figure 2 into 4-month blocks of the year is not justified and poorly discussed. For example, the wind farms I am familiar with routinely undertake blade inspection in summer when the average wind speeds are lower, and so this time period is likely to show the largest number of blade failures but this fact has no meaning. Blade failure in general, can accumulate over periods of years, so the month of its discovery is unlikely to be significant. An exception is possibly lightning damage which can be maximised at certain months of the year and can occur quickly. Lightning strike rates vary significantly over India, Chakraborty et al. (2021, extra reference below) but no attempt is made to relate this to the blade failure data.
The lack of novel information is reflected in the pedestrian style of the writing. Section 3.2 starts with “Blades are one of the largest components in WT” which is one of the worst examples of meaningless statements but there are others. The use of pie charts unduly complicates the presentation: replacing figures 1- 4 with tables would shorten the manuscript and give the information in a more readable form. The lack of axis labels on figures 2 – 4 makes them even harder to read.
Additional Reference
Chakraborty, R., Chakraborty, A., Basha, G., & Ratnam, M. V. (2021). Lightning occurrences and intensity over the Indian region: long-term trends and future projections. Atmospheric Chemistry and Physics, 21(14), 11161-11177.
Citation: https://doi.org/10.5194/wes-2024-55-RC3
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