Stochastic Optimal Operation of SOP-Assisted Active Distribution Networks with High Penetration of Renewable Energy Sources
Keita Yasuda
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper tries to analyze a convex model to optimize the open points integrated Energy Store and Distribution networks. Monte Carlo simulation and K-means are considered in process.
From my point of view, similar studies should be introduced that can help emphasize the conclusions.
For example 0ptimal Operation of Integrated Energy Systems under Uncertainties: Distributionally Robust and Stochastic Methods, Yang, Bo; Wang, Zhaojian; Guan, Xinping. US: Elsevier, Sep 20, 2023.
Optimal Operation and Market Integration of a Hybrid Farm with Green Hydrogen and Energy Storage: A Stochastic Approach Considering Wind and Electricity Price Uncertainties
Camuñas García-Miguel, Pedro Luis; Donato Zarilli Alonso-Martinez, Jaime; Manuel García Plaza; Gómez, Santiago Arnaltes. Sustainability; Basel Volume 16, No. 7, (2024): 2856.
For the rest, it seems like a logical and analytically valid development to publish once the conclusions are better.
Author Response
Answer: Authors thank the insightful and helpful comments to improve the quality of the draft. In order to response the comments and suggestions from this reviewer, the authors have included the introduction of the mentioned references in the draft. And the authors have included the explanations on the simulation section to better clarify the benefits of the introduction of SOP.
Here are the included explanation of references:
Moreover, a two-stage stochastic optimization model for the hybrid wind farm with hydrogen and energy storage systems is introduced in [22], demonstrating better performance compared to Monte Carlo and deterministic approaches in handling uncertainties. For the optimal operation of integrated energy systems, a distributionally robust approach is proposed in [23] to address uncertainties arising from renewable energy resources, load demand, and energy prices.
References added:
[22] Pedro Luis Camuñas García-Miguel, Donato Zarilli, Jaime Alonso-Martinez, Manuel García Plaza, and Santiago Arnaltes Gómez.Optimal Operation and Market Integration of a Hybrid Farm with Green Hydrogen and Energy Storage: A Stochastic Approach Considering Wind and Electricity Price Uncertainties. Sustainability, 16(7):2856, 2024. https://www.mdpi.com/2071-1050/16/7/2856. doi:10.3390/su16072856.
[23] Bo Yang, Zhaojian Wang, and Xinping Guan. Optimal Operation of Integrated Energy Systems Under Uncertainties: Distributionally Robust and Stochastic Methods. Elsevier, 2023.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis study presents the results of simulations that introduced SOP to improve the efficiency of utilization of solar power generation, a renewable energy source. The content of the simulation is technically valid, and the insights gained from the results are useful. Therefore, this manuscript can be published in Sustainability after addressing the specific comments listed below.
1. Page 1, lines 24-25; page 2, line 51; page 2, lines 58-59, page 2, line 79: Since DG, SOPs, and ADN are defined as abbreviations immediately before, only the abbreviations are needed here.
2. Abstract, line 5; Page 2, line 59, Table 1: On the other hand, BESS (for their first usage), VAR, and DER are not defined as abbreviations.
3. Page 2, line 54: Is it not Plug-in Hybrid Electric Vehicles (PHEVs) instead of Plug-in Electric Vehicles (PEVs)?
4. Page 7, line 212; page 8, line 228: The order of Figure 2 and Figure 3 in the text is reversed. Additionally, a more detailed explanation of Figure 2 is needed.
5. Page 8, line 235: The details of "Computational resources" are included, but they generally seem unnecessary. If there is a reason for detailing "Computational resources," please explain it.
6. Page 9, line 260: Is "Figure 5(c)" a mistake for "Figure 5(d)"?
7. Figures 4 to 7 and relevant discussions: A discussion on the influence of the six different source patterns shown in Table 1 on the results would be beneficial. More explicit discussions on the relationship between each result and PV, BESS, and SOP would also be helpful.
8. Page 9, lines 277-287: These two paragraphs discuss the efficiency improvements brought by the introduction of SOP, which is the core part of this study. Since this is an important section, it would be beneficial to emphasize the superiority of the SOP introduction, including the principles behind it, with a focus on the comparison of Figures 6 and 7.
Comments on the Quality of English LanguageOnly minor editing is required.
Author Response
Comments from Reviewer 2:
This study presents the results of simulations that introduced SOP to improve the efficiency of utilization of solar power generation, a renewable energy source. The content of the simulation is technically valid, and the insights gained from the results are useful. Therefore, this manuscript can be published in Sustainability after addressing the specific comments listed below.
Answer: Thanks very much for the comment and suggestions. We all believe that these comments for improving literature review of this draft are insightful and vital. In order to response the reviewer’s comments and suggestions, authors modified the draft according to the comments one by one. The revisions are shown by the contents with red color in the draft.
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- Page 1, lines 24-25; page 2, line 51; page 2, lines 58-59, page 2, line 79: Since DG, SOPs, and ADN are defined as abbreviations immediately before, only the abbreviations are needed here.
Answer: Thanks very much for the comment and suggestions. The authors adopted the abbreviations after the definitions in the entire context.
- Abstract, line 5; Page 2, line 59, Table 1: On the other hand, BESS (for their first usage), VAR, and DER are not defined as abbreviations.
Answer: Thanks very much for the comment and suggestions. The authors have included the full name of these abbreviations in the entire context.
- Page 2, line 54: Is it not Plug-in Hybrid Electric Vehicles (PHEVs) instead of Plug-in Electric Vehicles (PEVs)?
Answer: Thanks very much for the comment and suggestions. The authors have checked the abbreviation carefully and found that it is Plug-in Electric Vehicles (PEVs) in reference [14], not the Plug-in Hybrid Electric Vehicles (PHEVs).
- Page 7, line 212; page 8, line 228: The order of Figure 2 and Figure 3 in the text is reversed. Additionally, a more detailed explanation of Figure 2 is needed.
Answer: Thanks very much for the comment and suggestions. The authors have updated the figure 2 and 3 in the order in the draft. Moreover, the authors have included the explanations of figure 2 in the context.
To validate the proposed optimal operation strategy for ADN with an SOP, a 21-bus distribution system is adopted in case study, as shown in Figure 2. The 10-kV distribution network contains 6 PV plants and BESS installed at buses 3, 7, 9, 12, 16, and 20, respectively. Additionally, buses 20 and 14 are connected via an SOP, which is integrated with a BESS to provide power support for the system.
- Page 8, line 235: The details of "Computational resources" are included, but they generally seem unnecessary. If there is a reason for detailing "Computational resources," please explain it.
Answer: Thanks very much for the comment and suggestions. The authors deleted the computational resources in the context.
- Page 9, line 260: Is "Figure 5(c)" a mistake for "Figure 5(d)"?
Answer: Thanks very much for the comment. The authors have revised Figure 5(c) as Figure 5(d).
- Figures 4 to 7 and relevant discussions: A discussion on the influence of the six different source patterns shown in Table 1 on the results would be beneficial. More explicit discussions on the relationship between each result and PV, BESS, and SOP would also be helpful.
Answer: Thanks very much for the comment and suggestions. The authors have included the influence of SOP on the power outputs of PV sources and BESS in the system, shown by the red context in the revised draft.
Furthermore, the output power of each BESS vary from each other since the operation costs of BESS are different. Meanwhile the reactive power outputs of BESS are from -20 to 120 kVar to support system voltages. And the reactive power output of BESS at bus 3 is the highest during the peak hours (from 18:00 to 22:00). It is because that this load demand of this branch is much higher than other branches and BESSs at this branch would generate more reactive power to support bus voltages.
However, the outputs of reactive power are different, which is caused by the power outputs constraints, power flow constraints and load demand distribution in the system.
With SOP, the power outputs of BESS 1, 2, 3, 5 are close to each other, however, power outputs of BESS 4 and BESS 6 installed at buses 14 and 20 are opposite during peak hours. It is because that during the peak hours, load demand is transferred from bus 20 to bus 14. To conclude, the outputs of BESS are decided not only by operation costs but also by operation constraints of SOP.
- Page 9, lines 277-287: These two paragraphs discuss the efficiency improvements brought by the introduction of SOP, which is the core part of this study. Since this is an important section, it would be beneficial to emphasize the superiority of the SOP introduction, including the principles behind it, with a focus on the comparison of Figures 6 and 7.
Answer: Thanks very much for the comment and suggestions. The authors have included the benefits of SOP in section 4.2 in context with red color.
The SOP plays a pivotal role in enhancing the operational flexibility and efficiency of the distribution network, as validated by the results shown in Figure 4 to Figure 7. It smooths BESS power outputs and reduces PV power curtailments. Compared to Figure 5(d) and Figure 7(b), the reduction in PV power curtailments is over 90% in general, while still satisfying the operational constraints.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsIn my eyes, this is a high-level paper and worth publishing. I think there should be some overview of the content at the beginning of each section, For example, one paragraph should been inserted between “2. System Optimization Model” and “2.1. Linearized Power Flow Model”, between “3. Optimization Model and Convexation” and “3.1. Reformulation of Objectives”.
Author Response
Answer: The authors would like to convey their sincere thanks to the reviewer for providing valuable comments and suggestions. The included contexts are shown as follows.
Paragraph between 2 and 2.1:
This section introduces the model of an ADN with PV sources, BESS, and SOP with BESS. The operational model of the ADN includes the power flow model, the SOP model with power losses, BESS operational constraints in the SOP, the power loss model as part of the ADN operation model, and the active and reactive operation objectives and constraints for PV sources and BESS.
Paragraph between 3 and 3.1:
This section concludes the optimization objectives of the proposed models for ADN, which include SOP operation costs, PV operation costs (power curtailment costs), BESS operation costs, power losses of the ADN, and the utility power purchase cost. To convexify the optimization model, a second-order cone program (SOCP) is adopted to relax the power losses.
Author Response File: Author Response.pdf
