Research on the Non-Contact Pollution Monitoring Method of Composite Insulator Based on Space Electric Field^†

Round 1

Reviewer 1 Report

The paper presents the study about research on non-contact pollution monitoring method of composite insulator based on space electric field. Authors say, that insulator contamination threatens the safe work of high voltage overhead line. Contaminations result in flashover accidents. That is why electric field observation is expected to realize insulator pollution condition monitoring and contamination flashover in non-contact way. The paper presents spatial electric field distribution characteristics of 110 kV composite insulators. Authors propose non-contact monitoring method for composite insulator pollution, which is based on spatial electric field.

 

Comments and questions:

1. First chapter describes fundamental information about the insulators, which are used in overhead high voltage electric power lines. Authors present problems, which occur during the operation of the line. One of them is flashover or even breakdown, which is caused by pollution on insulator surface. There are many reason of the pollution, such as wind, agriculture activity, polluted air, and others.
2. Second chapter presents finite element simulation model for pollution insulator. Authors explain basic simulation settings, and simulation model. They describe properties of each dielectric material. Authors present pollution conditions setting method.
3. Some question – I think, conductivity of air is much smaller, 1x10(-22) S/m, not 1x10(-13) S/m.
4. Correct unit of conductivity is S/m, not s/m, s means second.
5. Chapter three shows space electric field distribution simulation results and analysis. Authors present electric field distribution of clean insulator strings, under surface pollution wetting condition, and under dry band arcing conditions.
6. Comments – fig. 3-5. Electric field has a unit [V], electric field stress or electric field intensity has a unit [V/m]. So, please correct the axis on figures.
7. Next chapter presents non-contact monitoring method for contaminated insulators. Authors explain effect of different pollution conditions on the space electric field of composite insulator. They shows changes in the amplitude of the electric field at three locations with different pollution states.
8. Chapter 5 describes made artificial verification test. Authors present structure parameters of the sample, and laboratory tests arrangement and its circuit diagram. Finally, they show comparison of various characteristic parameters of leakage current signal and spatial electric field signal under different contaminated insulator surface conditions.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear authors,

thanks for your interesting research work on the non-contacting detection of pollution on high voltage insulators. The paper has been organized very clearly and the simulations supported by small scale experimental tests showing good agreement on numerical results.

I have some general observations:

The introduction of the electric sensors and their supporting structures affects the distribution of the electric field distribution between it and the insulator. Is this being evaluated by the authors? Moreover, this structure could impact the withstand of the insulator on a live tower structure application. This aspect should have been mentioned in recommending the adoption of this methodology on live HVAC lines.

A single or double circuit presents multiple phases and related voltage. This creates a different voltage level on the space between and around the insulators. Could the authors indicate the impact of other phases on the measurement of their proposed device in a live system?

Another impact could be the necessity of a wider tower structure to accommodate a monitoring system for each insulator

In addition, I would like to suggest some editing to improve the clarity of your paper:

• In some part of the paper, sheds are referred as "umbrella skirt" term (i.e. Figure 1), meanwhile in other parts as sheds. I would suggest adopting the more common term shed for all the paper
• Page 12, Figure 10. I would suggest plotting the numerical data, instead of using the oscilloscope screenshot.  In addition, I have some notes:
  •  there is a strong contradiction on waveform labelling (i.e. the first one, in yellow colour, is labelled as Leakage current signal (a), then as applied voltage signal (b)). This impact the possibility to comment on the signal presented
  • On this figure, an interval is selected and named as "alpha" but no indication on the text. it could be useful for the authors to explain why this interval is important and indicated only in figure 10 b and not in c.
• Page 13, Table 3
  • I suggest removing "previous" and leave "simulation results" from the headings of column 4. This term "previous" could confuse the reader expecting two series of simulation results.
  • I suggest removing the unit from the individual cell and place on each table header, since the results are sharing the same scale. this to improve the clarity of the results for the reader.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

This paper is interesting and deals with an up-to-date topic. However, it is poorly structured and  to be improved. For this reason, I suggest that the paper is needed to rewrite in the present form and that the authors resubmit it by addressing properly the following items.

1. Abstract: Author write general information not related to his own work
2. Introduction: Author need to add references of related research work  such as 

• Effect of Uneven Wetting on E- Field Distribution along Composite Insulators
• Risk Assessment of Failure of Outdoor High Voltage Polluted Insulators under Combined Stresses Near Shoreline

Addition to this author need to add reference for years 2016 and 2018 as mentioned

Again, big gap of related research, author need to add reference given below with reference 5

• Effect of Cold Fog on Leakage Current Characteristics of Polluted Insulators

For example, literature  [15] need to add relevant reference, reference given below more appropriate to pointed out that the electric field distribution around the insulator

• The Effects of Salt Contamination Deposition on HV Insulators Under Environmental Stresses

3. Finite Element Simulation Model for Pollution Insulator

Author need to explain how drive equation 1 and what’s the relation between equation 1 and 4

2.2 Simulation model: Author need to explain boundary condition of model used for simulation

 2.3 Pollution conditions setting method: Author need to elaborate link equation 5 with simulation work

5. Artificial Verification Test: Author should explain the speed and direction of wind during test

 

6. Conclusions should be properly reflection of experimental and simulated work

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear authors, the introduced amends clarify well the underlined sections and now it is ready for publication. Very good work.

Reviewer 3 Report

Accepted as it