Remote Laboratory Testing Demonstration

Round 1

Reviewer 1 Report

The paper discusses at a very high level a cloud platform to exchange data, which to me has no particular relevance for power systems. Any book on Kubernetes discusses the topic in a more relevant manner. Also, the project VILLAS developed at University of Aachen is basically the same as JaNDER but is not cited in the paper.

My main concern is that the description of JaNDER is so high level that the paper looks like a report for an EU project. It may be adequate for such projects where carrying out actual research is not required and one has to justify why millions of Euros have been spent to make a software tool that any fourth-year computer science student would take a week to develop. But clearly, this is not research (and in fact no equations are included in the paper). And this has to be expected given that the paper is written mostly by people from industry.

The proposed platform, JaNDER is a simple and rusty software tool that allows exchanging data and, given the delays that are indicated in the paper, is not even good at doing that. The case study is not particularly relevant: OLTCs are very slow devices. No communication delay can ever harm their dynamic response. OLTCs, in fact, are often delayed a few minutes on purpose to avoid unnecessary changes of the tap ratio. The authors should test the proposed approach with faster controllers, e.g., some typical WAMS proposed in the literature. Note that the paper also fails in doing a good literature review.

I suggest that the authors present their tool at a booth paid by their company at some conference on power systems (e.g., ISGT Europe). This manuscript document could serve as a flier to give to people passing by the booth.

Author Response

Comment 1:

"The paper discusses at a very high level a cloud platform to exchange data, which to me has no particular relevance for power systems. Any book on Kubernetes discusses the topic in a more relevant manner. Also, the project VILLAS developed at University of Aachen is basically the same as JaNDER but is not cited in the paper."

Authors:

The communication platform disccussed in the paper enables many new power system testing because the proposed approach allows to integrate hardware/software of different labs. 

The paper does not aim to explain the architecture of a cloud based communication platform but it aims to show how a tool like JaNDER can be used to extend an HIL setup.

JaNDER is very similar to VILLAS. The main advantage of JaNDER is the simplicity of installation and use. Indeed it does not require any ICT skill.

A state of the art analysis has been added.

Comment 2:

"My main concern is that the description of JaNDER is so high level that the paper looks like a report for an EU project. It may be adequate for such projects where carrying out actual research is not required and one has to justify why millions of Euros have been spent to make a software tool that any fourth-year computer science student would take a week to develop. But clearly, this is not research (and in fact no equations are included in the paper). And this has to be expected given that the paper is written mostly by people from industry."

Authors:

Since the objective of the paper is the approach of laoratory coupling and not the test itself, the details of the optimization problem (with equations etc.) have not been reported. This has been highlighted in the paper.

The work behind the results presented is much more than a week. This should be clear to the reviewer that knows well VILLAS framework. JaNDER, like VILLAS, is  open source software. To make it easy to use several PMs have been spent. This is not a simple custom software for exchanging data.

Moreover, the few papers available in the literature and the high number of funds on this topic demonstrate that the objective of the paper is obviously at research stage. Many other aspects have to be investigated.

Comment 3:

"The proposed platform, JaNDER is a simple and rusty software tool that allows exchanging data and, given the delays that are indicated in the paper, is not even good at doing that. The case study is not particularly relevant: OLTCs are very slow devices. No communication delay can ever harm their dynamic response. OLTCs, in fact, are often delayed a few minutes on purpose to avoid unnecessary changes of the tap ratio. The authors should test the proposed approach with faster controllers, e.g., some typical WAMS proposed in the literature. Note that the paper also fails in doing a good literature review."

Authors:

The delays of JaNDER is in the range of tens of ms that is more or less the same latency of similar tools for data exchanging based on Internet. 

The considered test case (validation of a Centralized Voltage Control) is a classical test for smart grid application that could be performed with a HIL setup. Since the objective of the paper is to demonstrate that JaNDER can be used to extend a HIL setup, the selected test case is well justified.

Faster controller will be tested with this approach to stress the communication platform and evaluate its performance.

Some considerations have been added in chapter 5. 

Reviewer 2 Report

The paper presents JaNDER, a tool for integrating research infrastructures and exchanging data in real time. The structure and presentation of the paper are clear. The use of JaNDER in different tests have been provided. The performance of the virtual laboratory system relies heavily on the internet connection, so that (delay) outliers sometimes happen.

I recommend the paper is publishable in current form.

Minor typos:

Page 2, line 69: "could can" -> "could"

Page 8, line 255: "not" -> "no"

Author Response

The state of the art analysis has been extended.

Additional considerations have been provided in chapter 5.

Several typos have been corrected.

Reviewer 3 Report

This paper presents the results of a Horizon 2020 project on the integration of research laboratories and the online data exchange.

The results presented in section 5 support the theoretical background presented in the paper. However, the reviewer wants to draw the authors' attention to the following issues:

• The authors must present and analyze similar research presented in the literature, that is, the so-called "state of the art" of the subject under consideration.
• Please, define the meaning of the acronym DRTS at its first appearance.
• Check for typos, for instance “every single measurements” on line 223, page 7.
• Referring to Fig. 16, page 14: comment on the implications of a time delay of 3.76 seconds (the largest delay in the chain of actions analyzed) on an online approach.

Author Response

Comment 1:

The authors must present and analyze similar research presented in the literature, that is, the so-called "state of the art" of the subject under consideration.

Authors:

A state of the art analysis has been added.

Comment 2:

Please, define the meaning of the acronym DRTS at its first appearance.

Authors:

All the abbreviations have been explained.

Comment 3:

Check for typos, for instance “every single measurements” on line 223, page 7.

Referring to Fig. 16, page 14: comment on the implications of a time delay of 3.76 seconds (the largest delay in the chain of actions analyzed) on an online approach.

Authors:

Several typos have been corrected.

Some considerations regarding the latency of the communication platform and the delay of the OLTC controller have been added in chapter 5.

Round 2

Reviewer 1 Report

The answers provided by the authors are not really addressing my comments. Their main argument is "This [JaNDER] is not a simple custom software for exchanging data." Even if that were turn, which is not, no novel contribution is provided in the paper. Definitively reject.

Author Response

Reviewer:
The answers provided by the authors are not really addressing my comments. 
Authors:
The reviewer should explain better which comments were not addressed.

Reviewer:
Their main argument is "This [JaNDER] is not a simple custom software for exchanging data." Even if that were turn, which is not, no novel contribution is provided in the paper. Definitively reject.
Authors:
We would highlight that the novel contribution provided in the paper is not JaNDER itself but the demonstration of the possibility to test a control (such as CVC) using an extended HIL setup through a communication platform. The results show that JaNDER makes it possible, providing an effective, secure and easy to deploy communication platform.