Pilot Protection Based on Zero-Sequence Current Resistance-Capacitance Component for Large-Scale Inverter-Interfaced Power Stations
Round 1
Reviewer 1 Report
The paper has novel idea and it may be helpful for power sector. before final submission followings points needs to incarporate.
- Provide system simulation parameters like DG plant size, transformer rating,transmission line length and impedence etc.
-Provide numerical results of power flow i.e current, voltage and power for three-phase and three states: (a) from system (b) to load (c) to the grid.
-Provide the conventional Resistance basesd and proposed resistance capacitance based protection scheme in comparsion (either in Table or Figure)
- Provide complete current graphs for 3 to 4 second.
Author Response
Comment 1: The paper has novel idea and it may be helpful for power sector. before final submission followings points needs to incarporate.
Author response: Thank you very much for your approval. We really appreciate your comments.
According to your subsequent suggestions, we have done the following work to improve the paper.
1）First, in the appendix, we provide the detailed parameters of the simulation system shown in Figure 7, including the scale of distributed power plants, transformer rating, length of transmission lines, impedance and capacitance to ground;
2）Secondly, the abstract is revised to highlight the contribution of the paper. In section 3, the comparison between the traditional pilot protection and the proposed protection scheme is added to highlight the advantages of the proposed protection scheme;
3）Finally, in Section 4, for the setting and verification analysis of the proposed protection, the complete zero sequence current diagram on both sides of the tie line MN during the normal operation and fault period of the system under the conditions of different Rg resistance values and different fault locations is added to improve the readability of the simulation results.
Comment 2: Provide system simulation parameters like DG plant size, transformer rating, transmission line length and impedence etc.
Author response: We appreciate this suggestion for improving the paper. In the appendix, we provide the detailed parameters of the simulation system shown in Figure 7, including the scale of distributed power plants, transformer rating, length of transmission lines, impedance and capacitance to ground.
Comment 3: Provide numerical results of power flow i.e current, voltage and power for three-phase and three states: (a) from system (b) to load (c) to the grid.
Author response: Please see the attachment for details.
Comment 4: Provide the conventional Resistance basesd and proposed resistance capacitance based protection scheme in comparsion (either in Table or Figure).
Author response: We greatly appreciate the suggestion to improve this paper, which is very important for highlighting the contribution of this article. Please see the attachment for details.
Comment 5: Provide complete current graphs for 3 to 4 second.
Author response: Thank you very much for your comments, which are very useful for further improving the manuscript.
In the chapter of protection setting and verification analysis, when Rg is equal to 20 ohms and 150 ohms respectively, we have added zero sequence current diagrams on both sides of tie-line MN when faults occur in different areas. In addition, threshold values of starting elements with high fixed value and low fixed value are added in the current diagram to facilitate observation and determination of the action of starting elements under different fault conditions.
We have updated the original manuscript. In Section 4.3, we added zero sequence current diagrams on both sides of the interconnection line MN when faults occur in different areas under different Rg resistance values. See Figures 11 and 12 for details.
Reviewer 2 Report
In generally, when the resistance of the neutral point is large, it is difficult to consider the selectivity and rapid action of the current protection. Therefore, there is a protection mismatch with the inverter type power supply, and the low voltage crossing will lead to the risk of large-scale disconnection of the non-fault lines.
In this work, the authors establish the fault analysis model of large centralized IGPS acquisition system with grounding capacitance. Based on the analysis of fault characteristics, an economical blocking zero sequence pilot protection scheme is proposed. Finally, the effectiveness of the protection scheme is verified by an example.
In my opinion, this work is interesting and the arguments are convincing, which may arouse extensive research interest in the circuit community. I would like to recommend the publication of this manuscript in Sustainability.
A minor suggestion is that the authors can adjust the structure of the paper to make it more compact, so as to better guide the readers.
Author Response
Comment 1: In my opinion, this work is interesting and the arguments are convincing, which may arouse extensive research interest in the circuit community. I would like to recommend the publication of this manuscript in Sustainability.
Author response: Thank you very much for your approval. We really appreciate your comments.
Comment 2: A minor suggestion is that the authors can adjust the structure of the paper to make it more compact, so as to better guide the readers.
Author response: We appreciate your suggestions, which are very important to further improve this article. The revised contents mainly include the following four parts. Please refer to the manuscript for details.
- The summary has been revised to highlight the work and contribution of this paper.
- The formula and diagram are integrated to make the structure of the paper more compact and enhance readability.
- In the third section, the comparison between the proposed protection algorithm and the traditional zero sequence current protection is added to highlight the advantages of the proposed protection algorithm.
- The contents of Section 4 are integrated, and the simulation zero sequence current diagram is added, which corresponds to the protection action table and enhances readability.
