Study on Frequency Stability of an Independent System Based on Wind-Photovoltaic-Energy Storage-Diesel Generator
Round 1
Reviewer 1 Report
Review the Manuscript ID: electronics-2044606
Title: Study on frequency stability of independent system based on wind-photovoltaic-energy storage -diesel engine
In this work the authors proposed models of a multi-energy independent power grid platform that calculates the frequency change of the independent power system after the wind-photovoltaic-energy storage access.
The topic covered in the article is interesting and current.
The article is well structured, with an adequate bibliographic review.
Section 3, the power system and the simulation analysis descriptions, are very summarized. Authors should include more technical information about the power system and results.
Review the text and format of the document.
For example:
Some mathematical variables must be in italic when written in the text.
Please sort the keywords alphabetically.
Author Response
Dear Reviewer1:
Thank you for taking time out of your busy schedule to review the manuscript. Those comments are all valuable and very helpful for revising and improving our paper. We have studied comments carefully and have made corrections, which we hope will be met with approval. The revised portions are marked in red in the paper. The main corrections in the paper and the responses to the reviewer’s comments are as following:
1.Section 3, the power system and the simulation analysis descriptions, are very summarized. Authors should include more technical information about the power system and results.
Response: Many thanks for your thoughtful advice.
First, I explain the graphics of the simulation section in more detail. Then, I added some simulation graphics for different working conditions.
2.Review the text and format of the document. For example: Some mathematical variables must be in italic when written in the text. Please sort the keywords alphabetically.
Response: I have changed some variables in the text to italics and arranged the keywords in alphabetical order.
Reviewer 2 Report
I have the following observations:
1. The simulation section contains a very few results. I would like to see few more results in this section.
2. The list of references provided is very short. The authors should review more literature and strengthen the literature review/introduction section of the paper. For example have a look at the following papers that also focus on frequency control: https://doi.org/10.1109/ACCESS.2022.3183635, https://doi.org/10.1016/j.isatra.2021.01.052, https://doi.org/10.1016/j.ijepes.2020.106651, https://doi.org/10.3390/en14248408, and https://doi.org/10.1016/j.est.2022.104610
3. The authors have not compared their proposed method with the existing methods. I would like to see comparative results of the proposed method with the existing state-of-the-art methods.
Author Response
Dear Reviewer2:
Thank you for taking time out of your busy schedule to review the manuscript. Those comments are all valuable and very helpful for revising and improving our paper. We have studied comments carefully and have made corrections, which we hope will be met with approval. The revised portions are marked in red in the paper. The main corrections in the paper and the responses to the reviewer’s comments are as following:
1.The simulation section contains a very few results. I would like to see few more results in this section.
Response: Many thanks for your thoughtful advice.
First, I explain the graphics of the simulation section in more detail. Then, I added some simulation graphics for different working conditions.
2.The list of references provided is very short. The authors should review more literature and strengthen the literature review/introduction section of the paper. For example have a look at the following papers that also focus on frequency control:https://doi.org/10.1109/ACCESS.2022.3183635,https://doi.org/10.1016/j.isatra.2021.01.052,https://doi.org/10.1016/j.ijepes.2020.106651,https://doi.org/10.3390/en14248408, and https://doi.org/10.1016/j.est.2022.104610
Response: Thank you for the recommended literatures, I read these articles, and then selected articles A new optimal robust controller for frequency stability of interconnected hybrid microgrids considering non-inertia sources and uncertainties and A robust PID controller based on linear quadratic gaussian approach for improving frequency stability of power systems considering renewables to write them into the article.
3.The authors have not compared their proposed method with the existing methods. I would like to see comparative results of the proposed method with the existing state-of-the-art methods.
Response: I have compared their proposed methods with the existing state-of-the-art methods, and I have written down the shortcomings of their proposed methods.
Reviewer 3 Report
This paper presents the advantages regarding the stability of an independent system based on wind-photovoltaic-energy storage.
The subject is of maximum interest, but currently the content of the paper is difficult to read due to numerous writing errors. Also, the lack of a detailed description and a deeper analysis makes it difficult to understand the paper.
1. "diesel engine" is mentioned in the title. More correctly it should be written diesel generator.
2. The affiliation of the authors is not written.
3. At the keywords it is written: "droop calculation". These words are not found in the content of the paper.
4. In several places in the paper "Wind" is written with a capital letter. (e.g., line 112).
5. Simulink should be capitalized.
6. Throughout the paper, numerous notations in the text do not correspond to the notations in the formulas and figures. The symbols are not identical. In the formulas and figures the parameters are written with indices, in the text they are not. (e.g., Pu and Cp from lines 124 and 125 or Ebatt (t) and Emin_batt from line 143).
7. È in line 135 represents "transfer efficiency" and in line 137 "inverter efficiency". It would be good to differentiate with an index.
8. HZ should be Hz, in lines 266-268 and in Figures 8-11.
9. In formulas and figures parameters are with * as index, in text with * as exponent (e.g. K, formula 10 and line 192), please correct.
10. They should be explained better (line 219): "In the formula, P=PN-Pe. When ∆P=0, the stable frequency deviation of the system is zero."
11. Figure 7 should be annotated and described in much more detail.
12. All graphs should be analyzed much more.
13. Figure 13 shows the power of the diesel engine? I would think not.
14. Describe the two cases in which graphs a and b were obtained (Figures 12, 13 and 14).
15. The conclusions must be completed
Finally, I reiterate that the article must contain a more detailed description of the system and the conditions in which the graphically presented results were obtained.
Based on the above aspects, I cannot recommend this article to be published in the Electronics, unless it is significantly revised.
Author Response
Dear Reviewer3:
Thank you for taking time out of your busy schedule to review the manuscript. Those comments are all valuable and very helpful for revising and improving our paper. We have studied comments carefully and have made corrections, which we hope will be met with approval. The revised portions are marked in red in the paper. The main corrections in the paper and the responses to the reviewer’s comments are as following:
1."diesel engine" is mentioned in the title. More correctly it should be written diesel generator.
Response: I have changed the diesel engine in the text to diesel generator.
- The affiliation of the authors is not written.
Response: I have written the affiliation of the author.
- At the keywords it is written: "droop calculation". These words are not found in the content of the paper.
Response: Equation 10 has the use of the droop calculation principle, I have added the word droop calculation in the text explanation.
- In several places in the paper "Wind" is written with a capital letter. (e.g., line 112).
Response: I have changed the Wind in the text to wind.
- Simulink should be capitalized.
Response: I have changed the simulink in the text to Simulink.
- Throughout the paper, numerous notations in the text do not correspond to the notations in the formulas and figures. The symbols are not identical. In the formulas and figures the parameters are written with indices, in the text they are not. (e.g., Pu and Cp from lines 124 and 125 or Ebatt (t) and Emin_batt from line 143).
Response: I have unified the variables in the formulas and figures.
- È in line 135 represents "transfer efficiency" and in line 137 "inverter efficiency". It would be good to differentiate with an index.
Response: To solve the problem of duplicate variable definitions, I have redefined the variables, for example È 1.
- HZ should be Hz, in lines 266-268 and in Figures 8-11.
Response: I have changed the HZ in the text and in the figure to Hz.
- In formulas and figures parameters are with * as index, in text with * as exponent (e.g. K, formula 10 and line 192), please correct.
Response: I have unified the variables in the formula and the figures, both in the form of exponent.
- They should be explained better (line 219): "In the formula, P=PN-Pe. When ∆P=0, the stable frequency deviation of the system is zero."
Response: I have explained the meaning of each variable in the formula and given the formula ω=2πf, to explain the reason why ∆f is 0 when ∆P is 0.
- Figure 7 should be annotated and described in much more detail.
Response:I have described Figure 7 in more detail. For example, the grid system composite Marine cable includes 10.5kV and 35kV Marine cable lines. The power grid system mainly includes 10 transformers connected between the three voltage levels of 6.5kV, 10.5kV and 35kV, corresponding to 4 nodes respectively.
- All graphs should be analyzed much more.
Response: I have explained each figure in more detail. For example, according to equation (10), the effect on frequency amplitude when the load increases or decreases is simulated without considering the secondary frequency regulation of the system. When the load increases or decreases by 10%, the frequency decreases or increases by 0.2 Hz, and when the load increases or decreases by 25%, the frequency decreases or increases by 0.5 Hz. The frequency change corresponding to the load change is shown in Figure 8.
- Figure 13 shows the power of the diesel engine? I would think not.
Response: Figure 14 shows the output of the diesel generator when the load is constant and the wind and PV output is as shown in Figure 13.
- Describe the two cases in which graphs a and b were obtained (Figures 12, 13 and 14).
Response: I have described in detail both cases a and b of Figures 13, 14, and 15. In Figure a, the wind power output fluctuates relatively more, and the frequency fluctuates relatively more.
- The conclusions must be completed
Response:I have supplemented and refined the conclusion. As follows, this paper models a multi-energy independent power grid platform, calculates the frequency change of the independent power system after the secondary FM control strategy, and verifies the effectiveness of the control strategy with matlab simulation.
Round 2
Reviewer 2 Report
I have no more comments.
Reviewer 3 Report
The paper has been improved, I think it can be published in this form.
