Research on Applicability of the Practical Transient Voltage Stability Criterion Based on Voltage Magnitude and Sag Duration
Round 1
Reviewer 1 Report
The paper under review presents a simulation study aimed to investigate a possible validation of the practical transient voltage stability criterion.
The study presented by the paper is fairly fascinating and technically sound, the theoretical but also the simulation developments are well argumented and some interesting insights are given along the main body of the manuscript ; the presented simulation results are well organized and discussed even though their overall form should be improved.
From an editorial point of view, the paper seems to be timely presented and its actual form exhibits a logical organization of the required sections and subsections. The figures included in the work are quite clear and they enable the reader to understand the critical points of the main matter (generally). It has to be remarked that some parts of the manuscript requires further elaborations.
Despite the quite good form of the paper, it is the opinion of this reviewer that some improvements should be addressed. In particular, some comments are included hereafter to help the authors to improve their work. These comments are organized in form of a list of major/minor comments and a list of suggested (not mandatory) editorial hints.
MAJOR COMMENTS
a. The title of the paper claims that some "Proof" of the practical transient voltage stability criterion will be given along the presented manuscript, however no real proofs of such a criterion are given in this study (at least for what a "Proof" is intended). The indirect evidence of this fact is that the word "Proof" cannot be located in any other part of the paper's main text body. It is opinion of this reviewer that in the context of the presented work the word "Proof" can be too bold if placed inside the paper title. So, it is strongly suggested to fade this concept also along the title.
b. It seems to me that in section 5 the description of the Case Study is not sufficiently clear.
A listing of proper relevant parameters seems to be lacking. A more accurate description of the case study scenario is REQUIRED, in particular, even though the schematic view reported in Figure 7 seems to be sufficient, it is more indicated to include also an overview of the PSCAD/EMTDC simulation model.
MINOR COMMENTS
a. The concluding section should be better stated in order to fully summarize the main outcomes provided by the presented simulation results.
b. Please include some references to the related main results of subsection 3.1 and 3.2;
c. The Slip curves in Fig 9d are not clearly visible and does not provide a clear idea of what happens after the point 16.25 sec;
Editorial HINTS:
⦁ The captions of figure 8 and figure 9 are overlong and should be synthesized;
⦁ It is better to homogenize the quality and size of all the figures, please check;
⦁ There are some misaligned figure captions, please check:
⦁ line 122,
⦁ line 210,
⦁ line 258,
⦁ line 300
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The subject is well-known. There are a lot of papers in this domain. Anyway, the approach presented by the authors is quite original. I don't have experience related to the way the authors worked on it and decided to use this type of method. Most of the known methods are based on steady-state (eigenanalysis) and transient stability studies, including some dynamic models of loads. Anyway, the approach is quite interesting. The main problem is that there are fewer and fewer people interested in the domain.
Author Response
Thank you for your affirmation.
