Load Frequency Control (LFC) Strategies in Renewable Energy-Based Hybrid Power Systems: A Review

Round 1

Reviewer 1 Report

 

1. There are many grammatical mistakes and spelling mistakes. Such as line 48 on Page 2-“**of large no of renewable ….”, line 215 on Page 5, “…single are power …”. The authors should proofread the whole manuscript carefully.
2. The font size in Figures 4-15 should be well tuned to make it with the same font size as the main text.
3. There are some frequency regulation methods provided by renewable energy resources, such as Adaptive Power Point Tracking Control of PV System for Primary Frequency Regulation of AC Microgrid With High PV Integration, and Power Reserve Control with Real-time Iterative Estimation for PV System Participation in Frequency Regulation. These methods should also be reviewed.

Author Response

1. There are many grammatical mistakes and spelling mistakes. Such as line 48 on Page 2-“**of large no of renewable ….”, line 215 on Page 5, “…single are power …”. The authors should proofread the whole manuscript carefully.

Response: Grammatical and spelling mistakes are corrected. The proofreading for the whole document is performed. Each paragraph in the paper is checked for grammatical and spelling mistakes.

2. The font size in Figures 4-15 should be well tuned to make it with the same font size as the main text.

 

Response: The font sizes are adjusted. The font sizes are the same as the main text.

 

3. There are some frequency regulation methods provided by renewable energy resources, such as Adaptive Power Point Tracking Control of PV System for Primary Frequency Regulation of AC Microgrid With High PV Integration, and Power Reserve Control with Real-time Iterative Estimation for PV System Participation in Frequency Regulation. These methods should also be reviewed.

 

Response: The frequency regulation methods employing JAYA-PID, PSO-PID and GWO PID are widely used in Adaptive Power Point Tracking Control of PV System for Primary Frequency Regulation of AC Microgrid with High PV Integration, and Power Reserve Control with Real-time Iterative Estimation for PV System Participation in Frequency Regulation. These methods are discussed in this paper.

Author Response File: Author Response.docx

Reviewer 2 Report

Authors presents a very large review on LFC strategies.

The paper reads well, editorial quality needs some work, it falls within the scope of the journal, and english quality is acceptable.

As a review, authors spanned different families of controller strategies, including soft-computing based techniques such as neural controllers.

Concerning the references, I believe the number of citations is too large. A review should be selective, not inclusive. For this topic, I suggest reducing below 100 citations. 

The "future works" section is very interesting, and often missing when writing a review.

Minor remarks:

• Improve readability of Fig. 2
• Figure 4 can be reworked with a more technical system block representation
• In Fig. 6, i suggest "Metaheuristics" instead of "Evolutionary Computing", and "Evolutionary Strategies" instead of "Evolutionary Algorithms". Also, i would remove chaos theory, since its not a soft-computing technique.
• The figures with the bar diagramms (7 to 15) needs to be reworked completely. Most of the figure is occupied by the "title" (which should be in the caption), scientific notation with uniform digits should be used, and the bar plot should use log representation.
• Fig 15 is replicated. The second one (the one with the curve) gives very little insight and should be removed.
• For each family of controllers authors should draw conclusions on what problems are still open in literature (similar to the "future works" section)

Author Response

Review 2

Authors presents a very large review on LFC strategies. The paper reads well, editorial quality needs some work, it falls within the scope of the journal, and english quality is acceptable. As a review, authors spanned different families of controller strategies, including soft-computing based techniques such as neural controllers. Concerning the references, I believe the number of citations is too large. A review should be selective, not inclusive. For this topic, I suggest reducing below 100 citations.  The "future works" section is very interesting, and often missing when writing a review.

Minor remarks:

1. Improve readability of Fig. 2

 

Response: Readability of Fig.2 improved. Now it’s easy to read different sections of figures easily.

 

 

2. Figure 4 can be reworked with a more technical system block representation

 

Response: Reworking is performed adding more technical system block representation.

3. In Fig. 6, i suggest "Metaheuristics" instead of "Evolutionary Computing", and "Evolutionary Strategies" instead of "Evolutionary Algorithms". Also, i would remove chaos theory, since its not a soft-computing technique.

 

Response: "Metaheuristics" placed instead of "Evolutionary Computing", and "Evolutionary Strategies" placed instead of "Evolutionary Algorithms". The chaos theory is removed, since it’s not a soft-computing technique.

 

 

4. The figures with the bar diagram (7 to 15) needs to be reworked completely. Most of the figure is occupied by the "title" (which should be in the caption), scientific notation with uniform digits should be used, and the bar plot should use log representation.

 

Response: Said figures are reworked. The title is removed and replaced with a caption. Numbers are in scientific notation with uniform digits.

5. Fig 15 is replicated. The second one (the one with the curve) gives very little insight and should be removed.

 

Response: Thanks for your comment. Fig.15 has been removed now.

 

6. For each family of controllers, authors should draw conclusions on what problems are still open in literature (similar to the "future works" section)

 

Response: Conclusions on problems still open in literature added for PID, Fuzzy, ANN, SMC and TID controller. It gives insight about the existing problems in different areas. 

Author Response File: Author Response.docx

Reviewer 3 Report

• The contributions of the article must be emphasized in terms of originality and significance, which are not clearly stated.
• The abstract can be written in a more coherent way.
  • The contributions and novelty of this paper must be refined.
• The Introduction sections can be made much more impressive by highlighting your contributions.
  • The contribution of the study should be explained simply and clearly.
• The reference list needs to be checked, some information are missed from so many references (e.g publication year, name of the journal, issue,….etc).
• The reference list and the citation are needed to be double checked or entirely updated. I see jumping between the references and this may lead to mis-citation and mixing between the references to refer correctly to the cited data and info.
  • Ref [11] comes after ref. [26].
• Ref [17] comes before refs [15 &16]
• Ref [24] comes before ref [23]
• Ref [26] comes before ref [25]
• The reference list needs to be updated, the cited references sound enough but not up to date.
• Some minor typo errors and language related problems
• Double check the formatting when writing the figures’ titles
• Conclusion section should be rearranged. According to the topic of the paper, the authors may propose some interesting problems as future work in the conclusion.

Author Response

Review 3

1. The contributions of the article must be emphasized in terms of originality and significance, which are not clearly stated.

 

Response: The contribution and novelty of the present work are given as

1. A comprehensive review of a load frequency control for hybrid power systems
2. Review of different types of renewable energy systems tied with conventional power systems and the resulting load frequency control
3. Challenges and opportunities in load frequency control of hybrid power systems
4. Graphical analysis of Undershoot, Overshoot and Settling Time parameters performed for major load frequency schemes
5. Analysis of existing LFC techniques and their shortcomings. The suggestion about the future work for better LFC control

 

2. The abstract can be written in a more coherent way.

 

Response: Abstract is written again in a more coherent way. The insight into hybrid power systems provided addressing the issues in renewable energy systems. The interconnection issue in the power system is explained.

 

3. The contributions and novelty of this paper must be refined.

 

Response: Both contributions and novelty are refined. The work done in this paper which is innovative and unique compared to earlier papers is elaborated.

 

4. The Introduction sections can be made much more impressive by highlighting your contributions.

 

Response: The contributions in this paper are highlighted, this signifies the importance of work from earlier works.

 

5. The contribution of the study should be explained simply and clearly.

 

Response: The contribution of the study is elaborated. This paper explores 150 reputed journal articles hence the earlier work done, the deficiencies and future suggestions added.

 

6. The reference list needs to be checked, some information are missed from so many references (e.g publication year, name of the journal, issue,….etc).

 

Response: The references are checked thoroughly. Each of the articles contains the publication year and name of the journal issue.

 

7. The reference list and the citation are needed to be double-checked or entirely updated. I see jumping between the references and this may lead to mis-citation and mixing between the references to refer correctly to the cited data and info.

            Ref [11] comes after ref. [26].

            Ref [17] comes before refs [15 &16]

            Ref [24] comes before ref [23]

            Ref [26] comes before ref [25]

Response: Said corrections are made.

8. The reference list needs to be updated, the cited references sound enough but not up to date.

 

Response: Most of the references are latest with publication in the latest 3 years.

 

9. Some minor typo errors and language related problems

 

Response: The proofreading was performed for removing typo errors and language-related problems.

 

10. Double check the formatting when writing the figures’ titles

 

Response: The formatting is corrected while writing the figure's titles.

 

11. Conclusion section should be rearranged. According to the topic of the paper, the authors may propose some interesting problems as future work in the conclusion.

 

Response: The conclusion section is rearranged to give the author an insight regarding the overall work structure of the paper and the efforts made. The research and findings were summarized well while concluding the paper.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

No more comments.

Reviewer 3 Report

The paper can be accepted in the present form.