Power Curtailment Analysis of DC Series–Parallel Offshore Wind Farms

Round 1

Reviewer 1 Report

 

As a reviewer of the article:

Power Curtailment Analysis of DC Series – Parallel Offshore  Wind Farms

I formulated substantive and editorial comments.

Comments on the substantive content of the reviewed article:

In the introduction, the author wrote:

This paper an alyzes the relation between the impact of upper-voltage tolerance levels and wind farm  configurations on curtailment losses. This is validated using a case study performed on a  wind farm rated at 200 MW. This quantitative estimation of the energy curtailment losses  concerning wind farm configurations will be useful further to determine the optimal configuration of DC series-parallel wind farms.

 

1. I propose to emphasize the advantages of the proposed method in relation to the solutions proposed by other authors of the cited publications

 

2.The author wrote about the optimal configuration of DC series-parallel wind farms, therefore the summary should be more focused on the solution to the problem presented by the author.

 

Comments on editing the reviewed article:

1. Add (a) and (b) to Figure 1

2. Text containing a reference to Figure 2 should be placed before Figure 2.

3. Under Figure 3, provide an explanation of the symbols used (a), (b), (c) and (d)

4. Please consider modifying the subsection numbering

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper analyses and compares the power curtailment losses associated with DC series-parallel offshore wind farms with different configurations and overvoltage limits. In general, it is well written, with sufficient background provided and clear explanations/description of the conducted work.

However, areas of improvement exists and minor corrections should be made, as follows.

1. Some of the keywords are capitalized without a certain reason, please correct;

2. Define each quantity in all equations - check eq. (2), (3), (4), (5), (6). Especially eq. (5) and (6) are very unclear without describing all quantities involved.

3. The +/-5...+/-10 % tolerance levels for WT converters and the effects of exceeding these limits are mentioned several times in the paper (lines 104-105, then lines 130-133, 143-144). Similarly, the output voltage tolerance level is defined twice (line 136 and line 182). Another unnecessary repetition is on lines 172-176, as the author just repeats the ideas that have already been introduced a few lines earlier. I strongly suggest that the author avoids repeating the same information unless it is critical for the flow of ideas.

4. Figure 3 should also contain titles for each of the 4 sub-figures. Also, all figures (and tables) should be added in the paper only after they have been introduced in the text.

5. Please review and correct or rephrase the text on lines 359-362, as it is not clear.

6. Please include a short description of the decay constant of the wake model, as well as for the thrust coefficients. It does not need to be detailed, but only to give the reader a glimpse of their physical meaning.

7. Paper contains some minor typos, please read carefully and correct. Here are just some of them: line 87 "th"->"the", line 170 "turbine"->"turbines", line 172 "which is failed", line 315 "tase 1"->"case 1", line 333 "is nearly equal"->"are nearly equal", line 326 "are more"->"are higher", line 348 "are failed to operate", line 356 "was more", etc.

In addition to these points, the author should give more details regarding how the case study has been conducted, including the software used for it. It is not clear if the case study is based on simulations and other types of computer-based computations.

The paper should also include some description on how a faulty turbine on a string is bypassed so that the rest of the WTs in the string continue to provide power. Is a circuit breaker used to bypass the turbine? Are other breakers used to galvanically isolate the faulty turbine from the grid? None of the included figures illustrate how is this practically realized.

Finally, the author should include in the Conclusions some remarks regarding the novelty of this paper, e.g. in which way the presented results are different to those provided by other papers.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The author improved his paper and has addressed most of the comments he received in the previous round of the review.

However, one of my comments has not been addressed, namely some of the keywords are capitalized without a certain reason, so please correct before the final version is published.

Some typos are still present and in some places the text style/size is not consistent, e.g. title of Figure 1, there is an extra "3" on all sub-titles of Figure 3, text size in the Figure 4 is too large. All these should be addressed and the paper should be read very carefully before publication. It could be a good idea to ask a native English speaker or to use a professional editing service for the final checks of the language and style.

All the technical questions have been properly answered and I do not have other technical comments regarding this paper.

Author Response

 "Please see the attachment."

Author Response File: Author Response.pdf