Monitoring offshore wind farm power performance with SCADA data and an advanced wake model

Mittelmeier, Niko; Blodau, Tomas; Kühn, Martin

doi:https://doi.org/10.5194/wes-2-175-2017

Articles | Volume 2, issue 1

https://doi.org/10.5194/wes-2-175-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/wes-2-175-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 2, issue 1

Research article

|

28 Mar 2017

Research article |

| 28 Mar 2017

Monitoring offshore wind farm power performance with SCADA data and an advanced wake model

Niko Mittelmeier, Tomas Blodau, and Martin Kühn

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Final revised paper (published on 28 Mar 2017)
Preprint (discussion started on 17 May 2016)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Comments on ”Monitoring offshore wind farm power performace with SCADA data and advanced wake model”', Anonymous Referee #1, 15 Jun 2016
- AC1: 'Answers to comments of anonymous Referee #1 by Niko Mittelmeier et al.', Niko Mittelmeier, 26 Jul 2016
RC2: 'Monitoring offshore wind farm power performance with SCADA data and advanced wake model', Anonymous Referee #2, 16 Jun 2016
- AC2: 'Answers to comments of anonymous Referee #2 by Niko Mittelmeier et al.', Niko Mittelmeier, 26 Jul 2016
RC3: 'Review of Offshore Underperformance Detection by Mittelmeier, Blodau and Kühn', Anonymous Referee #3, 23 Jun 2016
- AC3: 'Answers to comments of anonymous Referee #3 by Niko Mittelmeier et al.', Niko Mittelmeier, 26 Jul 2016

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (26 Sep 2016) by Gerard J.W. van Bussel

AR by Niko Mittelmeier on behalf of the Authors (01 Nov 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (27 Nov 2016) by Gerard J.W. van Bussel

RR by Anonymous Referee #3 (28 Nov 2016)

RR by Anonymous Referee #1 (09 Dec 2016)

Suggestions for revision or reasons for rejection

General comments

My main comment is about the science part of the paper. The authors argue that in this paper they extend the work of Mittelmeier et al. (2013) by using SCADA data instead of met mast data. Obtaining environmental conditions from SCADA data is done in many other studies and fine-tuning wake models using SCADA is done daily. So it is perhaps the uncertainty part the relatively innovative thing of the paper but it is done using propagation of errors which is well-known and broadly used. So I think the editor needs to judge whether this is material for a science paper. Perhaps it is indeed very useful but I cannot see that.

On the other hand, the authors did an extensive improvement of the paper since the last version. However, there are still many instances in which the paper needs much improvement. English, particularly the use of past and present tenses, is not well used (choose one convention and be consistent). Also it looks like you move sections from some places but left the same sentences in different sections; the reader thus feel like there is no much care by the authors on writing the paper. Further there is still the problem with the references.

I have so many minor comments…

Minor comments

1. Page 1 line 9: do not define acronyms in the abstract
2. Page 1 lines 12-13: “averaging several measurement devices” One cannot do this but averaging measures (of the same type) performed by devices
3. Page 1 lines 20-21: “status of not being restricted in power production” Even if such a phrase is stated in the standard please try to use a better English form to say so
4. Page 2 line 2: delete “Using”. Also it looks like a “to find” is missing perhaps after “requires” and replace “leads” by “can lead”
5. Page 2 line 3: Once again this should be written as “in uncertainties (Albers et al., 1999, IEC 61400-12-2. 2013).
6. Page 2 line 16 “high uncertainties” of what?
7. Page 2 line 19 you mean “affecting” instead of “effecting”?
8. Page 2 line 25 should read “(Mellinghoff, 2007, Carvalho and Guedes, 2009).”
9. Page 2 line 26 it seems like you need a “because…”
10. Page 2 lines 28-29 should read “… a new method that uses relations between an observed turbine and all other turbines in the farm instead of the absolute values between model and measurements”
11. Page 2 line 30 replace “model is also based on” by “method uses”
12. Page 2 line 32 replace “model” by “method”
13. Page 3 line 7 “of these methods” you are showing only one method… that uses an expression for the uncertainty and a wake model
14. Page 4 line 16 delete “Having the measured… sensitivity”
15. Page 4 line 20 not the same n symbol in the three instances used
16. Page 4 line 21 replace “criteria” by “uncertainty criterion”
17. Page 5 line 1 replace “These causes the necessity” by “We need” and delete “for reanalysis purposes”
18. Equation 5. You are bringing the equations in a weird way. Equations are part of the text so in this particular case you finished a sentence “(xo,yo).” and suddenly you have the equation.
19. Page 5 line 21: All the constants in equation 5 have the dimension of degree?
20. Page 5 line 28: Add a comma after “wind direction theta”
21. In section 2.1.2. you describe the method to find out the wake affected turbines. Why not using the wake model for such analysis?
22. Page 6 line 7 Again bad referencing
23. Page 6 line 11 Change the text after the stop to “In Mittelmeier et al. (2015) three key parameters for the tuning of the wake model are identified”
24. Page 6 line 13 replace “visualizes” by “shows”
25. Page 6 line 14 replace “in 6.3 D” by “at 6.3 Dn” I guess it is Dn not D only
26. Page 6 line 16 delete the comma after speed
27. Page 6 line 21 Again a problem with the reference… should read “…proposed by Gaumond et al. (2014) to account for…”
28. Page 7 line 6 replace “phenomena” by “phenomenon” and delete “has”
29. Page 7 line 15 delete “as expected by the theory”
30. Page 7 line 17 you speak about Fuga suddenly
31. Equation 8: what is K?
32. Page 7 line 31-Page 8 line 1 reduce/rephrase that sentence because it is too long and not clear
33. Page 8 line 7: replace “include” by “includes”
34. Equation 9 make it in one line and delete the dot before the square root because it is not a dot product
35. Page 8 line 17: delete “Equation 9 explains…. (Bell, 2001)”
36. Page 8 line 20: should read “according to Ku (1966)”
37. Page 9 delete sentence between lines 8-9
38. Page 9 line 14 replace “have selected” by “select”
39. Page 9 line 21 delete first sentence
40. Page 9 last line replace “has been” by “is”
41. Page 10 line 3 delete “a Gaussian averaging of standard deviation”
42. Page 10 line 5 add “The coefficient of determination of “ before “A linear regression”
43. Page 10 lines 18-19 problems with the references and I am tired so it is up to you
44. Page 10 line 21 replace “model” by “method”
45. Page 10 from ~line 22 to Page 11 ~line 2 there are many sentences that were used before such as the sentence starting with “the wake model is supposed to” or “Therefore, our calibrated model has to be representative” and the wake drift explanation
46. Page 10 line 25 replace “have been” by “are”
47. Page 10 line 26 replace “identified” by “identify”
48. Page 10 line 27 replace “to be decreasing” by “to decrease”
49. Page 10 line 28 that is probably not the Fuga stability parameter but the dimensionless stability parameter… and the E should be e
50. Page 10 line 29 “set to more stable conditions”-> how more? By how much?
51. Page 11 line 5 then you need to say what is the drift for the other stabilities?
52. Page 11 line 8 “Figure 5… wind farm” you already showed and described this graph
53. Page 11 line 12-15 sentences that were already stated
54. Page 11 line 15 replace “have been” by “are”
55. Page 11 line 25 as above
56. Page 12 line 1 replace “have realized” by “find”
57. Page 12 line 2 “it is filtered out” you mean that you filter wind speeds below 5 m/s
58. Page 12 lines 8-11 already mentioned before
59. Page 12 line 12 replace “appears” by “appear”
60. Page 12 line 16 replace “has been” by “is”
61. Page 14 line 2 tests instead of test
62. Page 14 line 7 “were” instead of “have been”
63. Page 14 line 10 reference?
64. Page 14 line 14 calibration no recalibration
65. All graphs that use yellow should be changed and use other color
66. Figs 6 and 7 should have [deg.] as units in the x-axis

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RR by Anonymous Referee #2 (12 Dec 2016)

ED: Publish subject to minor revisions (review by editor) (22 Jan 2017) by Gerard J.W. van Bussel

AR by Niko Mittelmeier on behalf of the Authors (30 Jan 2017) Author's response Manuscript

ED: Publish as is (21 Feb 2017) by Gerard J.W. van Bussel

ED: Publish as is (05 Mar 2017) by Gerard J.W. van Bussel (Chief editor)

AR by Niko Mittelmeier on behalf of the Authors (06 Mar 2017)

Short summary

Efficient detection of wind turbines operating below their expected power output and immediate corrections help maximize asset value. The method presented estimates the environmental conditions from turbine states and uses pre-calculated power lookup tables from a numeric wake model to predict the expected power output. Deviations between the expected and the measured power output are an indication of underperformance. A demonstration of the method's ability to detect underperformance is given.