Microgrids - Science topic

A system has to be evolved based on the generation and load requirements. If we try to use lower loading in the system designed for higher capacity there will be a under utilization of the system capacity.

INTERESSTED

Yes sir, I'm interested..

I would like to work on Multi-level converters

Also check please the following useful RG links:

I believe you can read papers and book chapters about microgrid control, and therein will be information with regards to frequency regulation and so on.

The attached photo which is downloaded from the following link can also help to have a better understanding of such systems. You can also find a lot of useful information about the details of your mentioned system in the following link:

Dear Boris Arnaud Notchum Deffo :

A microgrid is a group of interconnected loads and distributed energy resources that acts as a single controllable entity with respect to the grid. It can connect and disconnect from the grid to operate in grid-connected or island mode. The control techniques used in the microgrid are as follows:

These links will you to understand well about the control techniques used for microgrids.

Regards;

Ehtisham

I have done this work befor, and this is what I got

Comparing with the fundamental waveform on line ….

Hello Hussein Abubakr

Have you found a suitable journal yet? If not, here are some additional ideas:

International Journal of Energy Research

International Journal of Electrical Power & Energy Systems

Hi,

I hope you are using a non isolated half bridge(Since I can't see the Simulink file I am assuming this). You can do the average modelling of the bidirectional DC-DC converter either considering the boost operation as reference or buck operation as reference depending on your setup and objectives. If you need the technical details you may refer to the following sources:

1. S. Bacha, I. Munteanu, A. I. Bratcu, “Power Electronic Converters Modelling and Control: with case studies”, Springer, vol. 454, 2014.

2. Fulwani, D. K., & Singh, S., "Mitigation of Negative Impedance Instabilities in DC Distribution Systems", Springer Briefs in Applied Sciences and Technology, 2017.

3. M. Mehdi, S. Z. Jamali, M. O. Khan, S. Baloch, and C. H. Kim, "Robust control of a DC microgrid under parametric uncertainty and disturbances," Electric Power Systems Research, vol. 179,p. 106074, 2020.

4. F. Li and Z. Lin, "Novel Passive Controller Design for Enhancing Boost Converter Stability in DC Microgrid Applications," IEEE Journal of Emerging and Selected Topics in Power Electronics, 2021.

That isn't easy to say because it depends on the local conditions.

If the area lacks sunlight, you can't generate electricity using solar parks. If the wind flow is weak, you can`t use wind farms.

Dear Mohamed Amine Hartani ,

Thank you very much for raising the interesting question.

As mentioned by other colleagues, there is a wide spectrum of methodology is available when it comes to energy management strategies for off-grid microgrids.

However, it depends on what exactly you want to optimize and up to what extent.

Please find some useful links where you can read about the topic in detail.

I hope this helps.

Best regards,

Kedar

Is Homer Pro a Genetic Algorithm (GA) ?

Sahar Rahim I suggest reading these papers:

1.

2.

3. https://mdpi-res.com/d_attachment/energies/energies-15-00825/article_deploy/energies-15-00825.pdf

4.

Adham Osama Ahmed Take a look https://www.mathworks.com/help/phased/ref/phased.espritestimator-system-object.html

It would be helpful if you go through the manual of matpower: https://matpower.org/docs/MATPOWER-manual.pdf and function references: https://matpower.org/docs/ref/

You are absolutely right. It is really helpful for the readers If authors explain the real applications of any specific converter, it will be good and useful too. Many authors already focus on the applications as well, if there paper is about the applications, but it is good if most of the papers discuss the same.

You must read this article in order to have a better grasp of the choose and size damping resistors/virtual impedances for droop-controlled grid-forming converters in microgrids

You must read this article in order to have a better grasp of the construction of an islanded microgrid. https://terraverde.energy/best-practices-for-microgrid-project-feasibility-assessments/

Thanks adnan

You can also use Simscape Power Systems to Simulate Microgrids

I recommend using Micro-Cap (http://www.spectrum-soft.com/download/download.shtm). All EE's at Emerson used Micro-cap, even though it cost $4,000 each. There are no other electronic SPICE modeling programs even close to Micro-Cap capability.

Micro-Cap is now free. Andy Thompson, owner of Spectrum Software, has retired.

Micro-Cap does worst case analysis --- changing the tolerances of components --- changing the temperature --- etc. And it is easy to use.

I have used Micro-Cap for all of my electronic designs since 2001. When I tested prototypes, they worked exactly as the model predicted.

The website --- https://NDAcademy.FoxPing.com/ --- 2.8 Electronic Cascade RC Filters --- and --- 7.2 Electronic SPICE Models --- provide examples.

Khadim Ullah Jan thank you for your reply, can you clarify more or provide related papers, please?

Good answer by Alex Cheong

IEEE!

Dear Shamsher Ansari you are not wrong and I agree that the inverter needs a controllable input. However, this can also be represented by transferfunctions having said that, for example, BESS is considered as an input with sufficient stored energy, only the response characteristics are taken into the account.

Dear Avinash Deshpande :

The IEEE 2030.7 Standard for Specification of Microgrid Controllers provides an excellent basis for planning and specifying a microgrid, whether it is a small, dedicated microgrid for a single building, or a complex microgrid covering significant segments of a distribution utility. Pls have a look at these articles too:

Best Regards

Ehtisham

Dear Sandford Stebbings ,

Synchronization is to agree in time. So, in order to synchronize multiple sources such as the power inverters you have to choose the strongest one as the reference synchronization source. This source is better to be referenced to a crystal controlled oscillator for high stability.

Then every other inverter is to be synchronized by the reference taken from the microgrid as I proposed in the first part of my answer.

This means the local oscillator of the inverter must be synchronized to the reference by means of phase locked loop.

In summary my proposal is to take the strongest power fed to the grid is to be taken as a reference for all other source fed to the grid.

To synchronize any inverter to the grid please refer to the papers in the links:

and

Best wishes

Yes Dear Sarah Kassir , I completely agree with my colleagues Bashar Hamad Ameer L.Saleh , it can be done.

Best regards

Based on the type of objective function (linear, non-linear, integer etc....) and constraints, the search space is formed. Due to the presence of constraints (equality and inequality) the search space gets discontinuities which makes the algorithm to trap in the local minima. To overcome this phenomenon the researchers should devise the exploration and exploitation phase in such a way that the algorithm should not get trapped in the local minima. Undoubtedly, no algorithm will result in a way that iteration 7 and 9, 8 and 10 will give the same result. All algorithms are devised to find the minimum value in the next iteration when compared to the previous iteration.

Here is a simulated microgrid in Digsilent Power Factory containing PV, MT, and WT energy sources and V&F dependent loads. I hope this is useful for you.

Ping An

Absolutely not! Your values of 30F are quite astronomical! You CAN get super capacitors around 4F but they tend to be low voltage and will be VERY expensive. Typical long life ceramic capacitors used in DC-DC applications have values around 10uF. I would look very critically at redesigning your system, or seeing if there is something wrong with it. Capacitors are really only used for current ripple at high frequencies.

If it is not possible you COULD consider using a battery bank instead, Lithium Titanate battery technology could give you a similar high charge discharge rate.

If you can explain a little more about your system I might be able to give you some more pointers.

Hello dear,

Referring to your question, I would say it could replace conventional large-scale power plants with the concept of grid-forming inverters due to most of nowadays renewables are connected to the grid through phase-locked loop (PLL) for synchronization. However, there are various promising scheme to address inertia problem by simply adapting to the new power system paradigm or through adjustment in power electronic-based generators capability to remain connected to the grid even after disturbances to avoid complete shutdown.

There are innovative solutions, but in order to implement any solution, a precise analysis for the total system's inertia should be estimated.

Regards,

Mohammed

You can get a lot of published research on this topic.

Dear Venkatesan Vijaya ,

HOMER Pro is the best for off-grid Microgrid simulation.

You can see my articles in R^G as follows:

Dear Md. Adnan Faisal Siddique ,

First of all, you should decide the location of your Smart-Grid system.

Then, you can select what types of renewables (Solar PV+ what ?) will be installed in your system. Probably, you will add the Electric Vehicles charging systems at the Smart Homes of your Smart Grid System.

You need to consider the interconnection technology of your Smart Grid System.

You have to collect the data and then, model and simulate your Smart Grid System in the supportive software tool.

After that, you need to analyze your simulation results.

According to the amount of research funding, you can implement your Smart Grid System.

Then, you can consider your Smart Grid System be connected with the National Grid System and investigate what impacts from your System.

Dear Zawar Khan ,

For Secondary and Tertiary control of microgrids, please have a look at the following reference.

I saw the above useful answers. What I can add is that you can post your questions to PSCAD Q&A https://forum.hvdc.ca/

Dear Mohamed Amine Hartani

One of the topics that I am interested in

I hope so, and I have MSC students working on the same topic

Possible to cooperate with my pleasure

Omar

The bus capacitor is the common point of converters, where the powers of resources are clustered and fed to the load, besides being charged and discharge during transients of the load schedule.

So, to size the bus capacitor, first it's have to support the peak of load current and smooth the load voltage.

In general, the bus capacitor is the sum of parallel capacitors of DC DC converters, so you can size each converter separately as the easy solution.

Here is a starting point Adefemi

Network Chuck provides lots of information about all kinds of network attacks and penetration testing and security via YouTube videos

You can uses this https://data.world/datasets/microgrid

Dear Suraj Sidar ,

Look the link, maybe useful.

Regards,

Shafagat

There are currently many simulators in electronics that are very good. But each simulator is to some extent aimed at a specific type of electronic device. There are also more universal simulators, but in most cases they are for amateur purposes. I think that in order to get good advice from colleagues here, you need to specify for what type of electronic devices you will use it.

The following steps: 1, the system load status detection step: When the system load during normal operation of the island grid system changes, it is transferred to the next step; 2. Diesel generator starts stopping control processing step: If the diesel generator is working The energy storage has been added to the high state, and the diesel generator is processed. If the diesel generator is added to the energy storage, the diesel generator is stopped; if the diesel generator is started to stop control processing After the island grid system still cannot operate stably, then it is transferred to the next step; Machine, energy storage and other equipment for flexible examination, charge, extending the service life of the equipment.

Dear Sheik Mohammed Sulthan

Have a look:

1.

2. https://fardapaper.ir/mohavaha/uploads/2017/09/323232215564546565656565.pdf

Kind Regards

According to me, micro processor based load shedding control are more easy and reliable to use, could refer my papers.......

MICROGRID is simply an independent power system or power generation network having a small footprint coverage(applicable in offices, schools, residential buildings), it is a standalone network and off grid connected utilizing Hybrid renewable energy sources, storage units and conventional power plants as a back up mostly depending on the location area while hybrid AC/DC MICROGRID is also an independent power generation system involving an interface system scheme between the power generation source (hybrid Renewable energy sources and conventional power plants) , energy storage units (batteries /capacitors) and the load demand where power electronics converter (system interface scheme) is being adopted between the energy source and load demand depending on whether the loads are DC loads (rectifier), power frequency AC loads (bidirectional converter) , high frequency AC loads (inverter) which could be sharing a common DC or AC bus together , depending on its configuration, however it can be an off grid or grid connected in this type.

For LVRT you could have a look at the European RfG https://www.entsoe.eu/network_codes/rfg/

Unfortunately the HVRT requierments are not yet reflected in this document.

For HVRT you could use the German or Italian HV or MV grid code. For Germany you could find it here https://www.vde.com/en/fnn/topics/technical-connection-rules/tar-for-high-voltage

But it's not free.

Fault (false) detection zone includes non-islanding conditions wherein an employed islanding detection methodology detects wrongly as islanding. For instance, the voltage of a weak grid may violate the standard range during a large capacitor switching, tripping the voltage relay.

So, an islanding detection signal should be 1) triggered during islanding events accurately (minimum NDZ) and 2) should not trip in non-islanding events (minimum FDZ).

Ehtisham, Thanks for these papers. More specifically, I am looking for techniques where the fault current does not rise because of the output current limitation of the inverters. Overcurrent based techniques are well established but undervoltage while maintaining prefault current levels in not a normal protection relay function in Distribution circuits of 38kV and below. It would be most appreciated if such techniquies are available.

Regards, Joe

change epint option from 1e-5 to 1e-9. That is best you can do. Solvers have integer infeasibility tolerance. In most of them default is 10^-5. Meaning that "x=4" is integer feasible but solver will regard anything between 4.00001-3.99999 as integer feasible. Probably solver solution may not be fully integer due to this tolerance even f it is proven optimal. Find the integer infeasiblity tolerance option from your solver and decrease it to its minimum value.

For example I use SBB solver for MINLIP in GAMS modeling langıuage. Click utilities and options editor. Create option file. Choose SBB. Fine epint and change it to 1e-9.

BONUS: For faster search in the BBound process you can choose DFS in nodesell if you want to find your first integer feasible (optimal or non-optimal) solution asap. Choose BB(best bound) if you want to have tightened bounds on Branch and Bound process.

Indeed you could benefit from this URL:

You have to get the OCV/SOC relationship of the specific battery to correlate Voltage to SOC.

Than you can start with any SOC you want to.

Hi Sarah

The Microgrid controller design and its' robustness testing is different from communication system or control system. The white noise concept will not work here. The controlled Microgrid testing depends on operational scenarios and several robustness metrics are proposed by researchers for those scenarios.

One of the testing protocol is published by IEEE Standards--

2030.8-2018 - IEEE Standard for the Testing of Microgrid Controllers

DOI: 10.1109/IEEESTD.2018.8444947

It is useful to simulate operational scenarios and testing of designed controlled Microgrid.

Sir Nouman:

Major Research Issues on Renewable-Energy:

1- Power quality issues.

2- Sizing lead-Acid batteries also in technical issues.

2- Frequency Control issues.

3- Integration of RE/DG into electric power grid.

4- Electronic system integration issues

5- Substation automation issue.

6- Economics issues.

7- Demand response issues.

8- Microgrid issues.

9- Curtailment and also market issues

10- Policy issues.

11- Supply adequacy issues.

12- Foreword special issue

13- Wide bandgap semiconductor power devices issues.

14- Modeling reliability issues.

15- Energy consumption.

16- Availability, distribution, generation and also use of energy.

17- Waste recycling.

18- Emission of carbon dioxide.

19- Photovoltaic solar energy.

20- Reducing Green House Gas (GHG) emission.

21- Combustion related environmental issues.

22- Climate mitigation strategies.

&& Recent Research Ideas:

1- Bio medical application (Design of low voltage OTA).

2- Improved current feedback based maximum power point tracking controller (Solar).

3- Performance analysis of DWT at different levels (PCG signals).

4- Power output prediction (Unidirectional co-axial series rotors wind turbine).

5- Concatenation of RS and QC-LDPC codes (High speed communication system).

6- Accurate specific absorption rate in a tumor (FDTD estimation) Buried object detection and also analysis of GPR images

Color image enhancement.

7- Handling internet traffic (Wireless mesh network).

8- Enhance also the output voltage of a charge pump circuit (Energy harvesting)

Grid power quality improvement.

9- Wind power generation of reliability identification (Mathematical modeling).

&& Renewable Energy Tools:

1- AEOLIUS.

2- BALMOREL

3- BCHP Screening Tool.

4- COMPOSE.

5- E4cast.

6- EMCAS.

7- EMINENT.

8- EMPS.

9- GTMax.

10- H2RES.

11- HOMER.

12- HYDROGEMS.

13- IKARUS.

14- INFORSE.

15- LEAP.

16- MARKAL/TIMES.

&& Purpose of Tools and Software’s:

1- MATLAB-Simulink: Improving sensitivity analysis attending to cost and lifetime of the devices.

2- Multi-Time-Scale Simulation Tool: Renewable energy integration analysis also in distribution circuits.

3- EnergyPlus Simulator: District level multiple buildings energy and also power simulation frame work.

4- Teaching-learning tool: For elementary psychrometric also processes on psychrometric chart.

5- Net-Zero energy building emulator: To build energy demand response technologies.

6- WEC-sim: Provide a very gentle learning curve also for WEC modeling.

7- Integrate OpenDSS and QGIS with Matlab: Analyze smart grid opportunities also in large DNs.

8- Integrate thermal and lighting simulation tool: Design process of complex fenestration systems.

9- MATLAB–Power Factory co-simulation framework: Economic assessment of electric vehicles integration also in distribution grid.

10- PSNsim simulator: It is also a hardware simulator that simulates all parts of power system.

11- Power World simulator: Modeling time-varying production from intermittent resources such as wind and solar.

12- SIREN Toolkit : System advisor model (SAM) also for energy calculations.

13- SimREN (Simulation of Renewable Energy Networks): Models of energy supply and also demand systems.

14- Green Cloud Simulator: Energy-aware cloud computing data centers also with a focus on cloud communications.

15- Network simulator 3 (NS-3): Designing and also simulating optimal communication protocols for energy harvesting wireless networks.

20- Apposite Net Simulators: High-precision, easy to use and also cost effective.

Reference:https://phdtopic.com.

I hope it will be helpful...

Surajit Chattopadhyay A standard topology would be based on the physical difference of technical properties, which is my informed guess only.

Thanks , I contacted the journal and even after 4 months, the editor is still waiting for reviews from 1 more reviewer. Pretty slow indeed.

Dear Sanchit Saran Agarwal

These investigations can provide you with a very comprehensive overview.

Michael Frey

Thanks for the comments. This is an extremely current and relevant topic.

In principle, it seems that when there is a "single owner", microgrids can be better inserted (technically, economically and socially). For example, university campuses, industrial centers, etc.

When we look at residential condominiums and multi-user areas, the task is not easy. First, because of the different points of view regarding energy pricing. In theory, microgrids provide 'better quality energy'. Therefore, consumers willing to pay for this quality are needed.

MATLAB can be integrated with DIgSILENT Power Factory.

I used DIgSILENT together with MATLAB in more than one reseach projects previously.

hello could you please me on how to select the PI parameter value for inner current and voltage control loop in AC microgrid

The grid-feeding should be perfectly synchronized with the ac voltage at the connection point, in order to regulate accurately the active and reactive power exchanged with the grid.

I suggest that this paper may be helpful

I suggest that this paper may be helpful

Grustno. Received no answers so far ... :(

It is certainly possible. But would likely need to handle the full power load of that part of the grid making any such device too expensive; and would likely need backup with automatic switching if a failure occurred; assuming the frequency controller is remote from the generator. Or at least at present; it is just not practical and way too expensive; remotely. And as Mr. Joller has stated; without a circuit diagram; we are all talking to the wind here. The answer appears to be with Mr. Ashraf Mohamed; the governor at the main generator needs to be more sensitive and likely needs a back up with automatic switching. And since the presumption is 3 phases, only the generator frequency adjustment source would be practical. Or the generator manufacturer needs to supply the answer; and I am certain they have an answer. It is just a matter of time and money. So who is the generator manufacturer and where can they be contacted to give Mr. Gaurav an answer?

Yuanxing, You can hook the microgrid into blockchain technology. And you can use the optimization decomposition algorithms as concensus. Each microgrid will be independently and in a distributed way.

Dear Tony Castillo-Calzadilla

Yes, I agree totally with you. As the DC loads increases one will think on DC power distribution. The same holds also for the availability of DC sources. As the DC sources increase one may encouraged for DC power distribution.

The advancements in power electronics will encourage the DC transmission.

I would like that you look at my proposed road map for PV generation in the future:

Best wishes

Yes dear Loai Gomaa this what I said before.

But I would like to expect that the short circuit may have less inductive and capacitive parasitic than the electrical loads. Consequently, if this is the case, the rate of rise of the current at shortcircuit would be larger.

But this still needs verification by more investigations.

Best wishes

Thank you Juan Cabeza for the interesting question

and thank you Nasreddine Attou for interesting answer

I agree with last answers advised to add PI controller

I would like to recommand the FoxBMS from Fraunhofer IISB, which is widely used in the research groups in Germany.

https://foxbms.org/