Cold Load Pickup Model Adequacy for Power System Restoration Studies

Round 1

Reviewer 1 Report

Dear authors,

Your manuscript investigates the impact of cold load pickup on power system restoration. Some comments:

1) There are some grammatical errors and typos that should be corrected before publication.

2) What is the novelty of this paper? In the introduction, I cannot tell the limitations of previous works. In the methodology, all equations were taken from previous references.

As is, the paper is an interesting case sample. 

Author Response

Thank you for your comments that helped us to further improve the manuscript!

1) We corrected some some typos and removed a misplaced comma.

2) We have extended the introduction which explains the difference between the current investigation and the existing state of the art (the third paragraph, starting with "Whereas [8] featured") to explain how our approach differs from existing investigations. The main novelty is the parameter fit of the analytically derived models to actual measurements and the subsequent comparison of time domain simulation results using the different models (ED, DED and the two stepwise load changes) to the original (normalized) raw data

Reviewer 2 Report

I am pleased to congratulate the authors of this article. The article is very comprehensive, very well written. I have only a few remarks that will help to improve the manuscript.

1. Please improve the introduction, making a paragraph to show what is new with respect to previous research. 

2. Please start the sentence on line 142 with a capital letter.

3. The aspect mentioned in the paragraph on lines 160 and 162 should be mentioned in the introduction in order to delimit the scope of the research from the beginning.

4. Please remove the comma from the line 201

5. Some capital letters are mising in Table 3

6. Please add the word "subsection" in paragraph between lines 394 and 398 if you consider necesary.

 

 

 

Author Response

Thank you for your comments that helped us to further improve the manuscript! We have addressed your remarks as follows:

1. We have extended the introduction which explains the difference between the current investigation and the existing state of the art (the third paragraph, starting with "Whereas [8] featured") to explain how our approach differs from existing investigations. The main novelty is the parameter fit of the analytically derived models to actual measurements and the subsequent comparison of time domain simulation results using the different models (ED, DED and the two stepwise load changes) to the original (normalized) raw data

2. Actually, the sentence starts in line 141 (old line numbers - line 146 in the current version) before equation (4). Therefore, "there" is not capitalized.

3. We extended the introduction by including the number of events and maximum outage duration considered in the evaluation.

4. Thanks for finding the mistake. We corrected it by removing the comma.

5. Thanks for pointing this out. Now, every entry starts with a capatial letter.

6. Thanks for pointing this out. We added the word "subsection" before "6.3"

Reviewer 3 Report

 In this paper authors have studied the impact of the cold load pickup phenomenon. The idea is investigated by using the time series measured after network outages in Austria and Germany.

This is a topic of interest. For authors of this paper, I have the following concerns:

1. Highlights of proposed method and results should be clearly reported in abstract.

2. It is recommended that authors mention the URLs after making the studied datasets available online. The URLs can be used to downloaded these datasets for the investigation and study purpose.

 3. A comparison between the proposed approach and the state-of-the-art counterparts should be made, preferably in tabular form, in the discussion section. This comparison table should list the key methods, parameters and findings which are used in each study.

Author Response

Thank you for your comments that helped us to further improve the manuscript! We have addressed your remarks as follows:

1. We extended the abstract to include the method of comparing time domain simulation results and the finding that exponential decay models leads to better results with respect to active power sharing among generators.

2. We have now published the datasets and replaced "will be published" in the data availability statement by "are available at...". We will update the description of the downloadable datasets with references to the paper (links, numbers of sections and tables) as soon as it is published.

3. We have extended the introduction which explains the difference between the current investigation and the existing state of the art (the third paragraph, starting with "Whereas [8] featured") to explain how our approach differs from existing investigations. Table 3 and Figure 13 show the results of our comparison of different simulation approaches. We are not aware of any other publication featuring such a comparison.

Round 2

Reviewer 1 Report

Dear authors,

After reading your revised version, I still think the originality and novelty of this manuscript are low, but the analyses and comparisons are interesting as a case sample. It seems to me that your main contribution is the application of a fitting function to represent cold load pickup curves with validation through simulations, which should be emphasized.

Author Response

Dear Reviewer,

thank you for your further comments.

As for the language issue: An additional check resulted in 7 language related (mostly typographical) changes. Those are highlighted in the submitted .pdf file in lines 93, 107, 224, 364, 371, 399 and 407

As for the focus on the application of the fitting function, we added a sentence (in line 30) stressing that the assessment was mainly done by conducting time series simulations and comparing the results. From our point of view, the main contributions are those listet from line 37 on (which includes providing parameter data, statistics and comparison of results from applying the CLPU models).