An Experimental Study on the Effect of Multiple Lightning Waveform Parameters on the Aging Characteristics of ZnO Varistors
Round 1
Reviewer 1 Report
The authors present a study of the response of ZnO varistors to varying pulsed lightning conditions. In principle, such studies, if the results are generally applicable, could be of interest. However, it appears that the study performs the study on a selected set of varistors from a given manufacturer, and it is unclear which of the results are of general validity for varistors overall. On the overall level, most of the results are intuitive. Then, the merit of the work is to list the specific response characteristics, but without knowing the manufacturer of the varistors and their model, it is hard to relate these values to anything beyond this study.
In addition:
1) The authors could start the introduction by explaining the current commercial use of ZnO varistors.
2) The authors state “In the experiment, the same batch of ZnO varistor square sheets of a certain manufacturer was selected.” How generally applicable are the results?
3) The paragraph on lines 55-89 looks very long. The authors should attempt to split it up in 3-5 subparagraphs to make reading easier.
4) In caption to Figure 2, the authors should list the different parts.
5) The authors talk about “ageing” with the pulses. But this appears to be the short-term effects . How is this long-term ageing? Will the varistor return to its initial state after enough time has passed?
6) The authors present statistical results of the heating of the varistor with varying number of pulses and pulse duration, also as a function of position on the varistor surface. To make the study more generally applicable, could the authors complement the statistical analysis with heat transfer modelling to reproduce the trends observed?
7) In Table 4, there are Chinese characters mixed with the Latin alphabet.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this paper the authors investigate the properties of ZnO varistors under multiple lightning impulse currents. Some points should be included within the manuscript in order to improve the publication.
- The abstract should be also rewritten in a more compact and successive way.
- The authors should describe in more detail the experimental setup and the experimental procedure in section 2.1. The authors should specify the characteristics of the components of the experimental setup.
- The authors should refer the standard that they used for the experiments in order to ensure the reliability of the experimental procedure.
- The authors should explain the contribution of their study in comparison with the corresponding experiments and analysis of other researchers.
- Please use only English language in table 4 and not Chinese.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
As it stands now, the study is performed on a specific varistor from a specific manufacturer, and it is unclear how generalizable the results are.
From the response letter:
"This article is mainly to explore the effect of multi-pulse waveform parameters on the aging of ZnO varistor, focusing on the relationship between the number of pulses and the pulse interval and the electrical performance parameters of ZnO varistor, so we analyzed the ZnO varistor of a manufacturer in multi-pulse Under the impact performance. This article is mainly to obtain the law of the influence of some multi-pulse waveform parameters on the aging trend of ZnO varistor."
If the goal is to show general trends, the underlying processes could be studied more; and possibly shown on varistors from multiple suppliers since currently it is unclear if the behavior is specific to the chosen varistor.
The heat transfer modelling takes quite a lot of space, but does not give much insight to explain the observed behavior in the experiments. The authors state in the abstract:
"The surface temperature distribution of the ZnO varistor under multi-pulse is not uniform, and the more pulses, the more uneven the temperature distribution, but the surface temperature rise has a nonlinear relationship with the number of pulses. The relationship between pulse interval, impact times and average surface temperature rise is established."
Such behavior would be good to model with (time-dependent) heat transfer for deeped understanding of the processes.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The revised version of the paper has been improved with respect to its original version and it appears to adequately addresses the comments and suggestions of the previous review as explained also in the Authors' responses to the reviewer comments.
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
The authors have included more appropriate analysis and the paper appears fit for publication.
