Study on the Power Quality of LED Street Luminaires
Round 1
Reviewer 1 Report
The introduction to the work presents the theoretical issues described in the literature well. Unfortunately, the way of writing is wrong, in my opinion. I give one example, but the Authors often use it: "As suggested in [15], the inrush electrical current…." The aim of the work is not clearly defined, and it follows from the article that Autors carried out classical measurements. Measurements of this type made by the Authors are nothing new. Therefore, these are not scientific research but classic case study. What was the DIALux software used for? Only to present drawings, what does the street look like in terms of the arrangement of luminaires? The discussion describes the measurements carried out and contains conclusions. On the other hand, the Conclusions section is an abstract of the article. Unfortunately, I’m afraid I have to disagree that the article in this form was published in a scientific journal whose IF is almost 4Author Response
Dear Reviewer:
Thank you kindly for your comments and suggestions concerning our manuscript entitled “sustainability-1827502”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have modified the article in different sections and, hopefully, we will come closely to the article version according with the journal requirements.
We have made modifications at lines 48-49, part of the literature introduction regarding the LED driver issues/quality.
The Fig.1./2./3., the “a) DIALux image” with the luminaires arrangement was removed, adding instead the DIALux simulation results for each street. Also, for each figure, we added at “c)” the LED luminaires layout and electrical energy supply schema for each street.
At the end, we compared the electrical current intensity and the THDI values for the three LED street lighting system, at normal operation.
The “4. Discussion” and “5. Conclusions” sections have been completely modified.
We tried our best to improve the manuscript and made some changes in the manuscript. We appreciate for Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Reviewer 2 Report
In general, it is a very nice article and a needed study, as this topic hasn't been analyzed very widely. Novelty in methods applied is not very high, but the dimming problem addressed is topical, especially in the smart lighting system context. The goal of this research should be described as hypothesis as a single statement, as the Intro part (which is a very good job done) already reveals where it is pointed. English is OK, and the structure is OK, but some issues can be found:
In lines 48-49, the source [15] speaks about LED driver issues/quality, furthermore, it seems more related to indoor lighting with low-power drivers, so it is not entirely relevant to the street lighting network, as most of the drivers have PFC circuit and the current waveform is more sinusoidal... I suggest explaining more and re-write the sentence laying focus on the "driver", not the grid (which is a passive element affected by drivers).
Also, the source [28] mentions "uncontrolled voltage spikes" (line76-78) it doesn't give any proof of such a statement, especially in LED lighting, which must comply with LVD and EMC directives. It is perhaps a general statement for sodium lamps, but not for LED. Please rewrite the sentence or add an additional source proving this statement.
In section2 a manufacturer and name of LED luminaires must be mentioned! It would be also great if a driver product name could be obtained. Otherway it can bring bad reputation to all manufacturers...
Fig.1./2./3. has a geometric layout both in a) and b) pictures... It is recommended to change the "a) picture" to light distribution (simulation) results instead, mentioning also the lighting class applied. Also, StreetA has 17 LED, streetB has 44 LED and StreetC has 227LED, according to measurement results it is doubtful that all 227 luminaires were measured. Please add some schematic of how the streets/lamps are placed/connected, and then illustrate the measurement point, to be clear where the measurements were obtained.
Line 175 needs to describe more specifically WHEN the measurements started to be recorded? As LED lamps also have a warm-up time of 15-30min before they take a fully stable regime, also other lamps in the grid must be already in a stable regime, especially as different Cases are mentioned further.
According to Table 4-6, we see that lines are unbalanced, thus how it affects the measurement and analytical results?
Section 4. "Discussion" must be re-written, as it is more like a "Summary", but not an analytic part logically coming out of measurements. Remember this is the most valuable part of the paper! At the moment there is nothing valuable to publish! Please do an analysis, similarily the literature sources you referred to (in the Introduction part). What if compared to standards/values/requirements, differences in regimes / dimmed stages, etc. As there are some problems, how they can be solved? Compare obtained results between the streets A-C... and so on.
Conclusions also should be improved accordingly to the outcomes in section 4.
The article is surely acceptable after revision.
Ansis Avotins (ansis.avotins@rtu.lv)
Author Response
Dear Reviewer:
Thank you kindly for your comments and suggestions concerning our manuscript entitled “sustainability-1827502”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have modified the article in different sections and, hopefully, we will come closely to the article version according with the journal requirements.
Response to comment: In general, it is a very nice article and a needed study, as this topic hasn't been analyzed very widely. Novelty in methods applied is not very high, but the dimming problem addressed is topical, especially in the smart lighting system context. The goal of this research should be described as hypothesis as a single statement, as the Intro part (which is a very good job done) already reveals where it is pointed. English is OK, and the structure is OK, but some issues can be found: In lines 48-49, the source [15] speaks about LED driver issues/quality, furthermore, it seems more related to indoor lighting with low-power drivers, so it is not entirely relevant to the street lighting network, as most of the drivers have PFC circuit and the current waveform is more sinusoidal... I suggest explaining more and re-write the sentence laying focus on the "driver", not the grid (which is a passive element affected by drivers).
We have made modifications at lines 48-49, part of the literature introduction regarding the LED driver issues/quality.
Response to comment: Also, the source [28] mentions "uncontrolled voltage spikes" (line76-78) it doesn't give any proof of such a statement, especially in LED lighting, which must comply with LVD and EMC directives. It is perhaps a general statement for sodium lamps, but not for LED. Please rewrite the sentence or add an additional source proving this statement.
We have made modifications, rewriting the sentences.
Response to comment: In section2 a manufacturer and name of LED luminaires must be mentioned! It would be also great if a driver product name could be obtained. Otherway it can bring bad reputation to all manufacturers...
We have added the LED luminaires manufacturer and types of the LED luminaires, for each street.
Response to comment: Fig.1./2./3. has a geometric layout both in a) and b) pictures... It is recommended to change the "a) picture" to light distribution (simulation) results instead, mentioning also the lighting class applied. Also, StreetA has 17 LED, streetB has 44 LED and StreetC has 227LED, according to measurement results it is doubtful that all 227 luminaires were measured. Please add some schematic of how the streets/lamps are placed/connected, and then illustrate the measurement point, to be clear where the measurements were obtained.
The Fig.1./2./3., the “a) DIALux image” with the luminaires arrangement was removed, adding instead the DIALux simulation results for each street. Also, for each figure, we added at “c)” the LED luminaires layout and electrical energy supply schema for each street. We are very sorry for our negligence regarding the power ratting of the LED luminaries for the Street C, the previous mentioned power ratting of the luminaires, between 55 W and 80 W, was selected from the tender procedure requirements, but the power ratting of the installed luminaires is lower, between 30.5 W and 55 W.
Response to comment: Line 175 needs to describe more specifically WHEN the measurements started to be recorded? As LED lamps also have a warm-up time of 15-30min before they take a fully stable regime, also other lamps in the grid must be already in a stable regime, especially as different Cases are mentioned further.
For each of the LED street lighting systems, we have performed several consecutive measurements, each of approx. 10-12 minute time frame. One of the purpose of the measurements was to cover all the LED street lighting systems daily operation. We have re-written the sentences.
Response to comment: According to Table 4-6, we see that lines are unbalanced, thus how it affects the measurement and analytical results?
We have re-written the sentence, the power supply system is balanced, but the system is unbalanced, especially for street C, with more LED luminaires connected on L3 phase.
Response to comment: Section 4. "Discussion" must be re-written, as it is more like a "Summary", but not an analytic part logically coming out of measurements. Remember this is the most valuable part of the paper! At the moment there is nothing valuable to publish! Please do an analysis, similarily the literature sources you referred to (in the Introduction part). What if compared to standards/values/requirements, differences in regimes / dimmed stages, etc. As there are some problems, how they can be solved? Compare obtained results between the streets A-C... and so on.
Conclusions also should be improved accordingly to the outcomes in section 4.
We have compared also the electrical current intensity and the THDI values for the three LED street lighting system, at normal operation. The “4. Discussion” and “5. Conclusions” sections have been completely modified.
We tried our best to improve the manuscript and made some changes in the manuscript. We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval.
Once again, thank you very much for your comments and suggestions.
Yours sincerely,
Horaţiu Albu
Round 2
Reviewer 1 Report
The structure of the article has been improved as suggested. It is still a classic case study, but if the journal and Special Issue Editors allow this form of the article, my opinion about the publication is positive.
Reviewer 2 Report
Seems most of the comments are taken into account and the paper is revised accordingly.
