Static-Voltage-Stability Analysis of Renewable Energy-Integrated Distribution Power System Based on Impedance Model Index

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors

 

Thank you for your contribution to our journal

The paper introduces the impedance model index for analyzing the static voltage stability of distribution systems comprising renewable energy sources (RES).

The authors provided a detailed calculation process and equations.

The inclusion of various test cases, such as the integration of RES and different network topologies, significantly strengthens the paper's credibility by demonstrating the accuracy of the proposed method.

Your work is commendable, and we appreciate the effort invested in producing a well-written manuscript.

In Section 2, the paper provides a comprehensive review and comparisons of traditional static voltage stability analysis methods. Furthermore, the inclusion of various test cases, such as the integration of RES and different network topologies, significantly strengthens the paper's credibility by demonstrating the accuracy of the proposed method.

Upon reviewing your submission, we noticed a resemblance to a method presented in reference [8]:

[8] Y. Song, D. J. Hill and T. Liu, "Static Voltage Stability Analysis of Distribution Systems Based on Network-Load Admittance 578 Ratio," in IEEE Transactions on Power Systems, vol. 34, no. 3, pp. 2270-2280, May 2019, doi: 10.1109/TPWRS.2018.2886636.

In [8], the admittance ratio is introduced as the voltage stability index, bearing a striking similarity to the concept presented in your paper. We would appreciate it if you could provide clarification on this matter. Specifically, how does your work differ from or build upon the ideas presented in reference [8]?

I recommended that the authors should compared the proposed method with other method summarized in the Table 1 and Ref. [8].

The conclusion is well consistent with the calculation results.

The references are appropriate

Best regards.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Title: Static Voltage Stability Analysis of Renewable Energy Integrated Distribution Power System based on Impedance Model Index

This paper proposed the impedance model index to easily evaluate voltage stability and demonstrated its effectiveness with example problems.

・Although the focus is on RE, is it also possible to think that the same applies to other power resources? Are there any benefits to the proposed method that are unique to RE?

For example, as EV chargers become more widespread, EV storage battery discharge as Vehicle to Grid will also increase in the future. If you have such a point of view, please add it.

・The various analysis methods listed in Table 1 are informative. Is it possible to show the relationship between the impedance model index of the proposed method and the indices of these existing methods, such as the singular values of the SVD method?

・If the Jacobian matrix used in existing methods is sensitive to parameter errors in the power system model (e. g. error of impedance information of individual branches), analysis may become difficult. In the case of the proposed method, how does parameter errors affect to the analysis accuracy?

・Is there a possibility that the impedance model index will be improved by appropriately setting P and Q on the resource side, that is, the voltage stability will be improved? If so, are there examples where the smart inverter function or power factor control function improves the voltage stability? Can you also show us such examples?

・This proposed method is a voltage stability analysis method. Is it possible to extend the method to a design method for a specific power supply system? The concept and prospect of applicability for design is described in the conclusion, but can you provide an concrete example of a specific design procedure of voltage stable power system?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors propose a static voltage analysis method for renewable energy integrated distribution power systems based on impedance model index.

 

Questions:

 

1. The use of indices and methods to evaluate voltage stability in systems with renewable electrical energy sources is not new. What are the weaknesses of existing methods and which ones do the authors aim to solve?

 

2. How did the authors arrive at the formulation of equation (1)? Why do values above 1 represent a case of voltage instability? Provide a reference for this method.

 

3. It is not clear how equation (3) was arrived at from equation (2).

 

4. Are renewable generation sources such as wind and photovoltaic plants considered as impedance and not power injections? How are the intermittency of active power generations considered in the model?

 

5. When determining and plotting the PV curves, did the authors consider the reactive power generation limits of the generators? They should usually be considered.

 

6. The authors do not present comparative results with methods already existing in the literature. What other existing methods evaluate voltage stability with the integration of renewable sources? What are the benefits of the method proposed by the authors compared to existing methods?

 

7. Does using impedance-based models bring conservatism in voltage stability analysis? Could using other models be beneficial?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors propose a static voltage analysis method for renewable energy integrated distribution power systems based on impedance model index.

 

The article has been improved, the contribution is good and all questions have been effectively answered.