Advanced Composite Materials: A Panacea for Improved Electricity Transmission

Round 1

Reviewer 1 Report

The manuscript entitled “applsci-1833566” dealing with composite has been reviewed. The paper has been nicely written but needs significant improvement. Please follow my comments.

 

 

1.     Please mention what was the gap in research and add a statement to the introduction.

2.     Please briefly introduce the process in the introduction.

3.     Add some quantitative results to the abstract.

4.     What is the purpose of presenting figures 1 and 2 in the introduction? Please explain.

5.     Add more detail to the conclusion and explain how your findings can support the text.

6.     Composite can be produced by additive manufacturing. Authors are encouraged to read and add the following new papers related to additive manufacturing of composites.

•   Additive manufacturing a powerful tool for the aerospace industry

•   Mechanical properties assessment of a 3D printed composite under torsional and perpendicular stress

•   Rapid consolidation of 3D printed composite parts using compression moulding for improved thermo mechanical properties

•   Topological design of the hybrid structure with high damping and strength efficiency for additive manufacturing

 

 

 

 

 

 

 

Author Response

Reviewer 1

1. Please mention what was the gap in research and add a statement to the introduction.

Works on transmission conductors abound in the literature. But no considerable attention has been given to the fact that the type of materials used in developing the conductor could be the source of the grid crisis

2. Please briefly introduce the process in the introduction.

      Done

3. Add some quantitative results to the abstract.

      The review results are more of qualitative and not quantitative. So, qualitative results have been added to the abstract.

4. What is the purpose of presenting figures 1 and 2 in the introduction? Please explain.

The purpose of Figures 1 and 2 is to justify the assertion that sub-Saharan Africa and some parts of Asia lack access to qualitative electricity.

5. Add more detail to the conclusion and explain how your findings can support the text.

      Done

6. Composite can be produced by additive manufacturing. Authors are encouraged to read and add the following new papers related to additive manufacturing of composites.

• Additive manufacturing a powerful tool for the aerospace industry
• Mechanical properties assessment of a 3D printed composite under torsional and perpendicular stress
• Rapid consolidation of 3D printed composite parts using compression moulding for improved thermo mechanical properties
• Topological design of the hybrid structure with high damping and strength efficiency for additive manufacturing

They have been reviewed and added.

Reviewer 2 Report

1) The literature review is too general. Moreover, the literature gap is not discussed.

2) In a current form, a novelty of the conducted research is unclear.

3) In present article, it needs to add the main research contributions of the present research compared with the existing research.

4) It is found that the manuscript is incomplete in all sense, moreover, the result and discussion section is missing.

5) The abstract and conclusion section need to be improved.

6) The limitations of the study are not considered.

7) The format of all the tables should be modified according to the journal guidelines.

Author Response

Reviewer 3

1) The literature review is too general. Moreover, the literature gap is not discussed.

The gap has been added as follows:

Among all the causes of the frequent power outages, poor maintenance of the grid, inadequate replacement of dilapidated conductors, and limitations of the conductor materials have been the principal issues. Works on transmission conductors abound in the literature. But no considerable attention has been given to the fact that the type of materials used in developing the conductor could be the source of the grid crisis. So, this review was aimed at identifying all the major problems encountered in overhead transmission grids. It looked into possible solutions to the problems. The bottom line was to increase the ampacity of the transmission grid so as to have a sustainable steady supply of electricity to the poorest nations of the world at affordable rates.

2) In a current form, a novelty of the conducted research is unclear.

Novelty has been clarified now as follows:

Works on transmission conductors abound in the literature. But no considerable attention has been given to the fact that the type of materials used in developing the conductor could be the source of the grid crisis. So, this review was aimed at identifying all the major problems encountered in overhead transmission grids.

3) In present article, it needs to add the main research contributions of the present research compared with the existing research.

The main research contributions were captured in the conclusion and recommendations as follow:

• Besides transmission conductor defects that bring about frequent power outages, other factors like lightning, bushfire, harsh weather, short circuit and overloading also contribute to frequent power outages. These are natural environmental hazards which may not be avoided. So, to cushion their effects, flame resistant nanomaterials are recommended for developing conductors.
• Al alloys are always preferred as overhead transmission conductors instead of Cu because Al is lighter in weight, cheaper and non-toxic. However, monolithic Al lacks mechanical and tribological properties requisite of transmission conductors. Hence, it is recommended that it should be reinforced with nanoparticles of CNTs, BN, TiC or SiC so as to improve its properties.
• It is recommended also that nanocomposites of Al should be developed and thoroughly characterized for possible use in power transmission conductors. It is expected that the proposed nanocomposites of Al would have more ampacity, higher thermal conductivity, lower CTE and better tribology than the existing transmission conductors.

4) It is found that the manuscript is incomplete in all sense, moreover, the result and discussion section is missing.

This is a review paper. So, I felt that results and discussion sections are not overtly discussed separately.  As individual papers are reviewed, their results are analyzed immediately.   

5) The abstract and conclusion section need to be improved.

The improved abstract is as follows:

The demand for electricity has increased drastically due to population explosion globally. Unfortunately, supply does not meet the demand. Consequently, transmission grid becomes overloaded culminating in frequent power outages. Worse still, the transmission grid lacks adequate maintenance and this has led to energy crisis in Africa and some parts of Asia. In this review, studies on the strength and weaknesses of existing transmission conductors were conducted. Also studied were natural and artificial phenomena that attack the overhead transmission networks. It was observed that besides inherent conductor defects, overloading, bush fire, short-circuit, harsh weather and lightning were the factors that ravage transmission grid. Hence, there is the need to develop more robust conductor materials that can withstand these challenges. The conventional conductors like all aluminum conductor (AAC) and aluminium conductor steel reinforced (ACSR) are challenged by low operating temperatures, among others. High temperature low sag (HTLS) conductors which were invented to tackle these shortcomings certainly have higher ampacity and better thermal rating than the conventional conductors. However, some challenges still devastate them. So, from the study conducted, it was discovered that developing advanced nano-based Al-composite conductor would help in ameliorating the challenges prevalent in the transmission grid. Such Al-nanocomposite conductor would possess higher ampacity and better thermal stability; and would be more durable and cost effective. 

The improved conclusion is as follows:

1. South Asia, Middle East/North Africa and sub-Saharan Africa are the three major regions mostly hit by frequent power outages.
2. AAAC and ACSR conductors are the conventional and most available transmission conductors in the market but are challenged by low operating temperature of 95 ^oC.
3. HTLS conductors are improved transmission conductors that can withstand temperature of 200 ^oC and above, hence, they have higher ampacity than the conventional conductors. ACCC and ACCR were found to be the best of the HTLS conductors in terms of efficiency and ampacity. They are still challenged by low strength (ACCC) and relatively high CTE (ACCR).
4. Besides transmission conductor defects that bring about frequent power outages, other factors like lightning, bushfire, harsh weather, short circuit and overloading also contribute to frequent power outages. These are natural environmental hazards which may not be avoided. So, to cushion their effects, flame resistant nanomaterials are recommended for developing conductors.
5. Al alloys are always preferred as overhead transmission conductors instead of Cu because Al is lighter in weight, cheaper and non-toxic. However, monolithic Al lacks mechanical and tribological properties requisite of transmission conductors. Hence, it is recommended that it should be reinforced with nanoparticles of CNTs, BN, TiC or SiC so as to improve its properties.
6. It is recommended also that nanocomposites of Al should be developed and thoroughly characterized for possible use in power transmission conductors. It is expected that the proposed nanocomposites of Al would have more ampacity, higher thermal conductivity, lower CTE and better tribology than the existing transmission conductors.

6) The limitations of the study are not considered.

The aim of the study specified the limitation as follows:

This review was aimed at identifying all the major problems encountered in overhead transmission grids. It looked into possible solutions to the problems. The bottom line was to increase the ampacity of the transmission grid so as to have a sustainable steady supply of electricity to the poorest nations of the world at affordable rates.

7) The format of all the tables should be modified according to the journal guidelines.

I didn’t format the Table so that the journal will be able to edit it to their taste.

 

Reviewer 3 Report

the article is interesting and can be published.

I would like more care.

1) at the end of the introduction it is necessary to say how the article is structured.

2) I would like the authors to go into more detail.

minor changes:

In the meantime, clarify that these are overhead lines, so the references to partial discharges could be left for conductors with insulation (perhaps to speak of corona effect).

My suggestion is also to go to the source, I found that some figures are related to paper 36, but he inserted them all the same by citing other papers. A better description would be necessary, for example figure 4 should make it clear that there is an inflection with the temperature, that is, a lower ampacity with increasing temperature, which can be seen in 36 but not in the paper presented here.

I would like line 129 to go into more detail explaining the critical temperature.

The paragraph on lightning strikes is interesting, but it must be said that there is the guard rope that protects the lines

Author Response

Reviewer 3

the article is interesting and can be published. I would like more care.

1) at the end of the introduction it is necessary to say how the article is structured.

Done

2) I would like the authors to go into more detail.

minor changes:

In the meantime, clarify that these are overhead lines, so the references to partial discharges could be left for conductors with insulation (perhaps to speak of corona effect).

Corrected

My suggestion is also to go to the source, I found that some figures are related to paper 36, but he inserted them all the same by citing other papers. A better description would be necessary, for example figure 4 should make it clear that there is an inflection with the temperature, that is, a lower ampacity with increasing temperature, which can be seen in 36 but not in the paper presented here.

I would like line 129 to go into more detail explaining the critical temperature.

“That which occurs when there is instantaneous current upsurge which may damage the transmission line if the material has low thermal conductivity and stability”.

The paragraph on lightning strikes is interesting, but it must be said that there is the guard rope that protects the lines

The guard rope (line guard) protects the transmission lines from physical or chemical damage and not from lightening strike.

Round 2

Reviewer 1 Report

The paper is ready to publish.

Author Response

Reviewer 1

1. Please mention what was the gap in research and add a statement to the introduction.

Reply 1

Works on transmission conductors abound in the literature. But no considerable attention has been given to the fact that the type of materials used in developing the conductor could be the source of the grid crisis

2. Please briefly introduce the process in the introduction.

      Reply 2

This is a review paper which is unlike research paper that is made up of Introduction, Materials and method, Results and discussion and Conclusion.. So the only process in review paper is reviewing and analysing results of authors. Though the paper has been sectioned as presented below:

      This review consists of five (5) sections.  Section 1 is the introduction; while in section 2, the strengths and weaknesses of transmission conductors were analyzed. In Section 3, further challenges of transmission grids were discussed; while prospective conductor materials were discussed in section 4. Section 5 contains conclusion and recommendation.

3. Add some quantitative results to the abstract.

     

Reply 3

The review results are more of qualitative and not quantitative. So, qualitative results have been added to the abstract as follows:

The conventional conductors like all aluminum conductor (AAC) and aluminium conductor steel reinforced (ACSR) are challenged by low operating temperatures, among others. High temperature low sag (HTLS) conductors which were invented to tackle these shortcomings certainly have higher ampacity and better thermal rating than the conventional conductors. However, some challenges still devastate them. So, from the study conducted, it was discovered that developing advanced nano-based Al-composite conductor would help in ameliorating the challenges prevalent in the transmission grid. Such Al-nanocomposite conductor would possess higher ampacity and better thermal stability; and would be more durable and cost effective.  

4. What is the purpose of presenting figures 1 and 2 in the introduction? Please explain.

      Reply 4

The purpose of Figures 1 and 2 is to clarify with facts and figures the assertion that sub-Saharan Africa and some parts of Asia lack access to qualitative electricity.

5. Add more detail to the conclusion and explain how your findings can support the text.

      Reply 5

      It was done as follows:

      This study was aimed at studying recent publications dedicated to increasing current in the transmission grid, improving the durability of transmission conductors, reducing the overhead cost of transmission networks and above all, diminishing frequent power outages. From the literature survey, the following conclusion and recommendations are made:

1. South Asia, Middle East/North Africa and sub-Saharan Africa are the three major regions mostly hit by frequent power outages.
2. AAAC and ACSR conductors are the conventional and most available transmission conductors in the market but are challenged by low operating temperature of 95 oC.
3. HTLS conductors are improved transmission conductors that can withstand temperature of 200 oC and above, hence, they have higher ampacity than the conventional conductors. ACCC and ACCR were found to be the best of the HTLS conductors in terms of efficiency and ampacity. They are still challenged by low strength (ACCC) and relatively high CTE (ACCR).
4. Besides transmission conductor defects that bring about frequent power outages, other factors like lightning, bushfire, harsh weather, short circuit and overloading also contribute to frequent power outages. These are natural environmental hazards which may not be avoided. So, to cushion heir effects, flame resistant nanomaterials are recommended for developing conductors.
5. Al alloys are always preferred as overhead transmission conductors instead of Cu because Al is lighter in weight, cheaper and non-toxic. However, monolithic Al lacks mechanical and tribological properties requisite of transmission conductors. Hence, it is recommended that it should be reinforced with nanoparticles of CNTs, BN, TiC or SiC so as to improve its properties.
6. It is recommended also that nanocomposites of Al should be developed and thoroughly characterized for possible use in power transmission conductors. It is expected that the proposed nanocomposites of Al would have more ampacity, higher thermal conductivity, lower CTE and better tribology than the existing transmission conductors.
7. Composite can be produced by additive manufacturing. Authors are encouraged to read and add the following new papers related to additive manufacturing of composites.

• Additive manufacturing a powerful tool for the aerospace industry
• Mechanical properties assessment of a 3D printed composite under torsional and perpendicular stress
• Rapid consolidation of 3D printed composite parts using compression moulding for improved thermo mechanical properties
• Topological design of the hybrid structure with high damping and strength efficiency for additive manufacturing

Reply 6

They have been reviewed and added as follows:

Authors opined that the panacea to this defect is the use of advanced production technique which produces impurity-free products, or the best when conventional method attains its technological limits and the application of advanced hybrid/nanomaterials with high resistance to abrasion and corrosion [18-21]. Some authors believed that 3D printing is one of the best ways of consolidating composites for better performance [22]. Lovo et al., [23] opined that infiltrated resin enhances most mechanical properties more than non-infiltrated resin.

Author Response File: Author Response.docx