Study on the Decrease in Air Dielectric Strength of DC Voltage According to the Ignition Properties of Combustibles
Round 1
Reviewer 1 Report
Generally, the manuscript presents interesting results and possesses good potential of publication in this journal. However, the following comments must be addressed to enrich the paper.
1) introduction is weak. please review some more papers to highlight the contribution
2) All abbreviations must be accompanied with their complete name.
3) please present the "density" in table 3 with SI unit.
4) English of manuscript needs revision.
5) the authors must clarify the reasons of using PP and PE polymers.
Author Response
Thanks for your comments. We have revised the contents as follows to reflect your opinions.
1) introduction is weak. please review some more papers to highlight the contribution
- References have been added to the introduction.
2) All abbreviations must be accompanied with their complete name.
- Abbreviations are written using full names.
3) please present the "density" in table 3 with SI unit.
- Edited according to your comments.
4) English of manuscript needs revision.
- Edited according to your comments.
5) the authors must clarify the reasons of using PP and PE polymers.
- Plastics are selected because there are many plastics among the combustible materials inside buildings. Experimental materials that generate a lot of conductive particles, such as PS, were excluded. This is because the conductive particles may affect the experimental results. A plastic with little occurrence of conductive particles was selected.
Reviewer 2 Report
I entered my comments into the pdf.
My major points of concern are:
- Too little background provided, i.e. how is dielectric strengt defined, tested and which requirements apply to power lines, etc.
- Abbreviations need explanation
Comments for author File: 
Comments.pdf
Author Response
We sincerely appreciate the reviewer’s comments. We have revised the paper to reflect most of your comments.
We could not proceed with the experiment in the absence of a fire. The equipment we used in our experiments had a maximum voltage of 60 kV. It was not possible to proceed with the experiment at a distance of 5 cm.
However, in the case of the wooden test, data similar to the dielectric strength derived from the references were confirmed. This reference has been added to the text.
Reviewer 3 Report
In my opinion the article is interesting and improve knowledge connected with characteristic of flammable materials as the potential sources of insulation breakdown and electrical accidents. However, I have some suggestions that could make the paper more clear and improve it:
- In point 2.2 the principle of cone calorimeter activity could be described in more details, in my opinion the only scheme is not enough.
- The equation in point 2.3 is not clear, symbols rs,rr and so on should be defined
- Some abbreviation are not clear (for example ACSR, HRR, HRRPUA)
Author Response
We sincerely appreciate the reviewer’s comments. We will respond to your comments as follows.
- In point 2.2 the principle of cone calorimeter activity could be described in more details, in my opinion the only scheme is not enough. ->
: Added description of cone calorimeter.
- The equation in point 2.3 is not clear, symbols rs,rr and so on should be defined
: Added explanations for abbreviations in equations.
- Some abbreviation are not clear (for example ACSR, HRR, HRRPUA)
: Added explanations for abbreviations.
Reviewer 4 Report
dear fellow researchers,
I find myself having to suggest that you totally revise the article as there are too coarse approximations.
1) The trigger for the perforation of the dielectric is not due to the voltage (kV), but to the electric field (kV / cm).
2) The electrical networks are not in DC as you wrote (those DC are very few and it is a technology not yet widespread), but as an experiment it is not totally wrong to work in DC.
3) in an AC network there are 3 conductors and the maximum voltage between conductors is square (3) the voltage between phase and ground.
4) the danger path to be considered for triggering is that between conductor and pylon or between two different conductors. Not between conductor and ground (22 m).
5) the effect of proportionality between conductors on the basis of different sections is not like the one you chose on page 5, on the contrary if conductors with a smaller radius are used, the electric field is larger than in the case of conductors with a greater radius! And it doesn't have to be proportional to 22m!
6) the bibliography is very sparse to proceed with a publication.
My advice is not to throw away the work done, but to rely on an electrical engineer who works in high voltage and who guides you first on a more efficient model on field theory and then use the measurements made, which are certainly good. to describe in detail what happens.
Author Response
We sincerely appreciate your comments. We will respond to your comments as follows.
1) The trigger for the perforation of the dielectric is not due to the voltage (kV), but to the electric field (kV / cm).
: We agree with your opinion. Corrected the expression.
2) The electrical networks are not in DC as you wrote (those DC are very few and it is a technology not yet widespread), but as an experiment it is not totally wrong to work in DC.
: In Korea, we are making technical standards for DC voltage. Therefore, experiments were conducted with DC voltage.
3) in an AC network there are 3 conductors and the maximum voltage between conductors is square (3) the voltage between phase and ground.
: Thank you for your comments.
4) the danger path to be considered for triggering is that between conductor and pylon or between two different conductors. Not between conductor and ground (22 m).
: According to Korean technical standards, the separation distance between high-voltage transmission lines (over 400kV) and combustibles is suggested as 22m.
5) the effect of proportionality between conductors on the basis of different sections is not like the one you chose on page 5, on the contrary if conductors with a smaller radius are used, the electric field is larger than in the case of conductors with a greater radius! And it doesn't have to be proportional to 22m!
: Our experiment is meaningful in confirming that the decrease in dielectric strength is similar when different materials burn regardless of the radius of the wire.
6) the bibliography is very sparse to proceed with a publication.
: References have been added to the paper.
We acknowledge the lack of explanation on the main points of the paper. Thanks again for your comments.
Round 2
Reviewer 1 Report
the manuscript has been modified appropriately and therefore, can be accepted in this journal
Author Response
I think your review was of great help to my article.
Thank you very much for your review.
I hope you always have a good day.
thank you.
Reviewer 2 Report
please see comments in the pdf
Comments for author File: Comments.pdf
Author Response
I have revised the article to reflect your detailed review.
I think your review was of great help to my article.
Thank you very much for your review.
I hope you always have a good day.
thank you.
Reviewer 4 Report
the authors did their utmost to correct the article. I noticed that for other reviewers the paper could be published. Considering that the intention is not to establish new standards but to find an application, there is no impediment to publication even in the presence of in-depth electric field studies. For a subsequent paper, I would suggest having an electrical engineer who works with the electric field and discharge phenomena give a reading.
Author Response
I think your review was of great help to my article.
Thank you very much for your review.
I hope you always have a good day.
thank you.
