Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The abstract describes the research methods and key findings but fails to explicitly highlight the specific innovations of this study compared to existing research on zero-sequence quantity analysis in IT-type grounding systems. It is recommended to add a brief comparison of the limitations of existing methods and clearly emphasize the technical contributions of this work.
2. In Chapter 2, a large number of literatures related to "artificial intelligence, hybrid neural networks, fuzzy control" (e.g., [29–33]) are cited. These research directions have weak relevance to the main theme of this paper, which focuses on mathematical modeling and theoretical analysis of zero-sequence quantities. It is suggested to replace them with more core literatures in the fields of "IT systems, single-phase grounding, zero-sequence voltage/current modeling, and mining power supply networks".
3. The paper proposes multiple simplified assumptions during the development of replacement schemes (e.g., ignoring line impedance and transformer winding parameters), but fails to analyze the extent to which these assumptions affect the accuracy of the results. For instance, line impedance cannot be completely neglected in actual mining distribution networks. It is necessary to quantify the applicable scope of the assumptions or verify the robustness of the model through sensitivity analysis.
4. The current derivation directly presents the results of Kirchhoff's equations (e.g., Equations 342 and 346), while lacking intermediate derivation steps and symbol definitions. This makes it difficult for readers to reproduce the calculation process. It is recommended to include key intermediate equations or steps in the appendix or main text.
5. Although various combinations of C and R parameters are presented, there is no explanation as to whether these parameters are derived from actual mining systems, typical IT network standards, or assumed values. It is suggested to add a "table of engineering application parameters within a small range" or label "typical/extreme conditions".
6. The entire paper relies solely on theoretical analysis and calculations, without any measured data or experimental platform verification. It is recommended to at least include: a comparison with data from typical mining power supply systems, or simple experimental measurements of zero-sequence voltage waveforms, or simulation verification (e.g., based on PSCAD, Simulink) to enhance the credibility of the research results.
7. Some contents are repeatedly described throughout the paper (e.g., "capacitive-dominated behavior", "transition from capacitive to resistive-capacitive characteristics"). It is suggested to compress the repeated paragraphs to improve logical clarity and make the paper more concise.
8. The current conclusion tends to summarize the obtained results but lacks an extension to future work. For example, verifying the method under different network topologies, expanding the research by introducing adaptive protection algorithms, or extending the study under multi-point grounding/transient resistance variation models.

Comments for author File: Comments.pdf

Author Response

Thank you for your review.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This work addresses the well-known problem of ground faults in IT networks, but focuses on the less frequently analyzed load-side fault situation and the impact of zero-sequence parameters. The novelty lies primarily in the compilation and analysis of amplitude-phase relationships for theoretical models. However, the lack of experimental validation and comparison to existing methods limits the level of innovation.

Review Comments for the Authors
1. Structure and Clarity

Please shorten and organize the introduction, more clearly indicating the research gap and the purpose of the work.

Excessive repetition in the results sections, especially figure descriptions, should be reduced.

It is recommended to include concise summaries at the end of each subsection.

2. Methods

Please justify the adopted model simplifications (omission of resistance, harmonics, losses).

Include clear definitions of all symbols used in equations and graph descriptions.

It is recommended to add a diagram presenting the analysis logic and the sequence of the methodology steps.

3. Presentation of Results

It is recommended to shorten the curve descriptions in the figures and highlight only the key conclusions.

Please provide units and axis symbols (especially in Figs. 8–9).

Repeating identical information in different sections should be minimized.

4. References

Please select the literature: remove items that are loosely related to the topics of zero-sequence and ground-fault protection.

It is recommended to add recent publications on high-resistance short circuits, load-side fault detection, and modern protection algorithms.

Please link citations more directly to the sections of the text being discussed.

5. Practical Value

It is recommended to include at least one example of the application of the results or a short comparative simulation with existing detection methods.

It is recommended to indicate how amplitude-phase relationships can be specifically used in selecting protection settings.

Please consider discussing the limitations of the models and potential directions for further research.

6. Conclusions

Conclusions should be concise and focused on the key achievements of the work.

Please emphasize the novelty and practical significance of the results.

Comments on the Quality of English Language

The text is generally understandable, but there are numerous linguistic issues:

• repetitive structures and excessively long sentences,
• inconsistent technical terminology,
• occasional calques and structures typical of literal translation,
• imprecise use of conjunctions and logical constructions,
• incorrect sentence order in places,
• descriptive passages are excessively wordy, making it difficult to understand.

The language requires editing for a scientific style, shortening and simplifying the syntax, and standardizing the technical vocabulary.

Author Response

Thank you for your review.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised manuscript has addressed the key technical issues and no major problems were identified in the content. The research design, experimental validation, and conclusions are logically consistent and scientifically sound.

Minor revisions are only required for language expression:

Refine the wording of some sentences for better clarity and fluency, avoiding awkward phrasing or redundant descriptions.

Standardize the use of technical terms and ensure consistent expression throughout the manuscript.

Check and correct minor grammatical errors or improper punctuation usage.

It is recommended that the manuscript be accepted after the above minor language revisions.

 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, thank you for your review. We are attaching a file with our answers. 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,
Thank you for submitting the revised version of your manuscript. The improvements introduced in this version are clearly visible, particularly in the areas of methodology clarification, contextual background, and practical relevance. Below I provide detailed comments and suggestions for further refinement.

1. Strengths of the Revised Manuscript

• The introduction now presents a well-defined research gap and stronger connection to relevant literature.

• The methodology has been significantly improved by adding justification for modeling assumptions and including the description of the laboratory setup.

• The scientific contribution is clearer, especially regarding the combined amplitude-phase analysis of zero-sequence parameters and the identification of new vector phenomena.

• The conclusions are more comprehensive and better linked to the obtained results.

2. Major Comments (requiring attention but not structural changes)

2.1. Presentation of Results

Although the results are now clearer, several descriptions remain overly detailed.
Suggestion: Please shorten the narrative accompanying Figures 4–9 and highlight only the main analytical findings.

2.2. Figures

A number of figures still lack complete axis labels, units, or uniform formatting.
Suggestion: Please revise Figures 4–9 by adding missing units and ensuring consistent graphical style across all plots.

2.3. English Language Quality

While the language has improved considerably, the manuscript still contains long sentences and complex constructions that may reduce readability.
Suggestion: A final professional linguistic edit is recommended to enhance clarity and ensure consistent scientific style.

3. Minor Comments

1. In Section 4.2 and 4.3, some mathematical expressions could benefit from clearer formatting (spacing and symbol definitions).

2. Please ensure all symbols used in equations are introduced before appearance.

3. Some citations are still placed too generally; linking them to specific statements would strengthen the scientific argument.

4. Consider adding a short summary subsection at the end of Section 4 to consolidate the key findings from all amplitude–phase characteristics.

5. A few sentences in the Discussion section repeat information stated earlier and could be shortened without loss of clarity.

4. Evaluation of the Bibliography

The reference list is now more coherent and relevant. Nevertheless, a few items are still only indirectly connected to the core topic.
Suggestion: Consider verifying whether all cited works meaningfully contribute to the context of zero-sequence fault analysis in IT-type networks.

5. Final Assessment

The manuscript has been substantially improved and now meets the scientific standards required for publication after minor adjustments. The work presents meaningful analytical insights into zero-sequence behavior under complex ground-fault conditions and contributes valuable knowledge for the development of protection devices in IT networks.

Comments on the Quality of English Language

The quality of the language is improved: sentences are shorter, more structured, and there are fewer calques. Nevertheless, the text still requires professional editorial correction in terms of academic style and terminological precision.

Author Response

Dear Reviewer, thank you for your review. We are attaching a file with our answers. 

Author Response File: Author Response.docx