Alternative Methodology to Calculate the Directional Characteristic Settings of Directional Overcurrent Relays in Transmission and Distribution Networks
Round 1
Reviewer 1 Report
1. Please explain in the article how the sensitivity analysis was performed (using mathematical relationships).
2. Did the authors use other algorithms to compare the results, e.g. Levenberg-Marquardt algorithm, to solve the optimization problem?
3. Please add 1-2 references from the Energies journal.
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors presented in the paper a new approach or an alternative the settings for directional overcurrent elements (direction determination characteristic) based on the short-circuit sensitivity analysis as an optimization problem. The objective function must optimize the only decision variable RCA (relay characteristic angle) from the eq.1. However, the authors should consider the following remarks to improve the quality of paper:
The authors write “Section 3 presents comparative results between the application of the traditional methodology and the proposed alternative…” but in this context, they should revise the discussion on the contributions of the paper. In particular, this reviewer cannot distinguish the new findings of this paper and the existing approaches in the literature. The references used to support the state of the art are too few (only two references, 8 and 9). The authors should expand the list of references in the context in which the topic is important and numerous studies have been conducted in the last years. Instead, this reviewer suggests the authors to exactly mention what is new compared with existing approaches and why the proposed alternative is needed to be used instead of the existing methods. In this context, introduction should be a reorganization to accentuate highlight the advantages and disadvantages of the approaches from the literature in relation to the proposals of the authors. A nomenclature list with abbreviations and notations should be introduced at the paper ends. The proposed approach are an optimization problem using an objective function and constraints. The authors must emphasize these constraints accordingly. Also in the results section the author must compare the results with another paper from the literature. The conclusion can be revised. This reviewer strongly suggests to improve the flow of conclusion section. Start with a brief explanation of the paper goal (like the abstract), but make sure that the conclusion should be different from the abstract. Provide the main findings/ claims. Explain the numerical findings of the simulations. Clearly explain, what are the significant findings and why your paper is really important. And finalize the conclusion by providing one or two suggestions for future work (like the last paragraph from the conclusion).The authors must consider the aforementioned suggestions and resubmit.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Dear authors, the suggestions are clearly improved reported to the first review.
I clearly understand that you are the specialists in the directional overcurrent relay and i friendly suggest of the tendentious comments from the response 2, the following paper, which also consider these topic:
Zhu, Y.; Zheng, T.; Wang, M.; Zhao, H.; Wang, X. An Improved Directional Relay Adapted to a Distribution Network with IIG Integration. Energies 2019, 12, 3345. Bakar, A. H. A., Mokhlis, H., Illias, H. A., & Chong, P. L. (2012). The study of directional overcurrent relay and directional earth-fault protection application for 33 kV underground cable system in Malaysia. International Journal of Electrical Power & Energy Systems, 40(1), 113-119. ETC.Author Response
Please see attachment
Author Response File: Author Response.docx
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The submitted paper is quite interesting, but from the point of view of protection practitioners, the presented study is not ready to be used, even if the authors said that they have used it in Columbia. May be in the local conditions there the method presented is applicable.
Reviewer 2 Report
The paper presents an alternative methodology for the calculation and verification of the settings defining the performance of the direction determination characteristic in directional overcurrent elements.
The paper is well written. However, a light review may help to correct some minor errors. In addition, the authors must clarify the doubts expressed below.
In the paper is not clear the improvement included in the paper in comparison with the reference [10]. In particular, the differences in the methodology, in the opinion of the reviewer, not justify a second paper with the same topic. For this reason, the authors must be clarifying the improvements/differences between the present paper and the previous paper of the same authors.
Reviewer 3 Report
The authors presented an alternative way of calculating directional overcurrent relay settings. The method has been presented with reasonable details and validated with theoretical analysis as well as practical relays from different manufacturers. In general, the proposed method looks promising. However, there are a few concerns which should hopefully be addressed:
1. On page 11, line 339, it is confusing how to justify "the most adequate polarizing 340 quantities for the 67N element"
2. In chapter 2, it is unclear why the sample system has been chosen. Any particular reason why the case studies weren't carried out on a test system?
3. In chapter 3, some of the results seem to be identical for both fixed and variable k except objective function. It is unclear what difference could the objective function result bring.
