Dear Masoud

A microgrid is an electrical system that includes multiple loads and distributed energy resources that can be operated in parallel with the broader utility grid or a Small, independent power system. It Increased reliability with distributed generation, Increase efficiency with reduced transmission length, and Easier integration of alternative energy sources.

while A smart grid is a modernized electrical grid that uses information and communications technology to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity. Transmission and operations: wide‐area monitoring, 

control and protection.

Thanks and Regards

Dear Masoud

A microgrid is an electrical system that includes multiple loads and distributed energy resources that can be operated in parallel with the broader utility grid or a Small, independent power system. It Increased reliability with distributed generation, Increase efficiency with reduced transmission length, and Easier integration of alternative energy sources.

while A smart grid is a modernized electrical grid that uses information and communications technology to gather and act on information, such as information about the behaviors of suppliers and consumers, in an automated fashion to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity. Transmission and operations: wide‐area monitoring, 

control and protection.

Thanks and Regards

In the same way, I just want to add that, microgrid permit to generate electricity from many small energy sources. It is an alternarive approch to integrate small scale distribute energy ressources while smartgrid is accordint to what Vika Shagma says.

best regards

In short microgrid grid means distributed generation on small scale rather than centralized generation and centralized control may be through e.g. renewable energy sources.

Smart grids are those controlled through advanced technology like telecommunication system.

What is the resource of energy in smart grid? Is it distributed or centralized generation ??

Generally the computerized, load dispatched center of area located generally at center of load area, from where distribution of total generation carried out economically along with, the monitoring/control of complete system load frequency control(stability point view) is called the smart grid. All individual, micro grid of small substations are monitor and control, if needed by smart grid.(refer my paper, "Microprocessor based automatic load shedding controller......"In U.S micro grids are generally no man's grid.

All resources of energy (micro grid) are monitored by smart grid, and load distribution is done economically.

But the Installation costs of Smart Grid are much higher when compared to Micro grids... Is it like that?

The difference between smart grids and smart microgrids is scale, the types of decision makers and the potential rate of change. While smart grids take place at the utility and national grid level, involving the large transmission and distribution lines, smart microgrids are smaller scale, require fewer decision makers and have faster implementation.

I may add a little more to Vikas Sharma's Answer.

Micro Grid can be considered as a sub set of Smart Grid  that is controlled through advanced technology like telecommunication system. Also  Nano Grid can be cosidered as a subset of Micro Grid. Nano Grids may be bigger than microgrids (in some places it's true already)

    #     MicroGrids Would Enhance Smart Grids

           Darrell Delamaide

  http://www.energybiz.com/article/13/09/microgrids-would-enhance-smart-grids

     #    Understanding Microgrids as the Essential Architecture of Smart Energy

      Toby Considine et al.

   http://www.gridwiseac.org/pdfs/forum_papers12/considine_paper_gi12.pdf

Our vision of the smart grid architecture is recursive; each

grid can be composed from a number of microgrids, and each smart microgrid replicates the architecture of the overall smart grid. A customer interface may front a home or commercial building, or an office park or military base.The office park and military base may contain their distribution network, their own generation, and their own

customer nodes. There is no architectural limit on this recursion; recent commercial products  provide room - level microgrids that support a single service, and manage generation, storage, and distribution internally.

             We use the term cloud to represent a multimodal , multi -

participant system wherein energy decisions are made, and energy

s executed. The cloud may or may not be  in the building, on the site, or located elsewhere. The cloud is not tied to a particular technology in use today.

The cloud is not tied to a specific application contained in any of

energy using or producing systems in the microgrid

    #   smart grid wins in energy storage, metering and more

        nanogrids may be bigger than microgrids (in some places it's true already)

   http://www.smartgridnews.com/artman/publish/Business_Markets_Pricing/Read-all-about-it-smart-grid-wins-in-energy-storage-metering-and-more-6449.html#.U-EWH6P2sec

P.S.

What is the difference between a microgrid and a smartgrid?.

Microgrid grid means distributed generation on small scale rather than centralized generation and centralized control may be through e.g. renewable energy sources.

Smart grids are those controlled through advanced technology like telecommunication system.

I support as Abdul Rauf Bhatti ...

A microgrid  consists of LV distribution systems having wind, solar, etc or any combination as small DG  units. A smart grid may or may not be a combination of microgrids.

microgrids are developed to supply local small scaled loads. A smart grid can supply large loads with the help of communication and automation technologies

microgrid considers the utilization of distributed energy systems in order to imrove the reliability and flexibility of the electricity. smart grid aims to combine intelligence technologies with electricity to imrpove the convenience and reliability of the whole electricity. micro grid is design for a small scale usually for a certain community while the smart grid is designed for the whole electricity system. They do not have any difference on the energy sources utilized.

microgrid considers the utilization of distributed energy systems in order to imrove the reliability and flexibility of the electricity. smart grid aims to combine intelligence technologies with electricity to imrpove the convenience and reliability of the whole electricity. micro grid is design for a small scale usually for a certain community while the smart grid is designed for the whole electricity system. They do not have any difference on the energy sources utilized.

microgrid considers the utilization of distributed energy systems in order to imrove the reliability and flexibility of the electricity. smart grid aims to combine intelligence technologies with electricity to imrpove the convenience and reliability of the whole electricity. micro grid is design for a small scale usually for a certain community while the smart grid is designed for the whole electricity system. They do not have any difference on the energy sources utilized.

microgrid considers the utilization of distributed energy systems in order to imrove the reliability and flexibility of the electricity. smart grid aims to combine intelligence technologies with electricity to imrpove the convenience and reliability of the whole electricity. micro grid is design for a small scale usually for a certain community while the smart grid is designed for the whole electricity system. They do not have any difference on the energy sources utilized.

I would rather saying, there is no difference between Micro grid and smart grid in  respect to load, source of generation, AC or DC except smart control system for efficiency and reliability in the system. Smart Grid Consumer Collaborative (SGCC) and others find that the average consumer knows little about how electricity is generated, distributed and consumed, the impact of using it, or how to maximize efficiency and cost savings. 

Normally, both terms are too close to each other. However, smart grid is more generalized word used for microgrids.

smart grid obtained when the control at large scale with developing technologies ensuring economic, security and reliability constraints of ( ensemble (microgrids_transmission level) + ensemle (microgrids _distribution level)) is reached

MicroGrid = small smart grid

Smart Grid = smart macro grid( utility grid)

Microgrids are the subsystems of smart grid.

MGs and SGs are totally different. 

In short  answer  :

Smart Grid is any electrical grid + IT at all levels .

Micro Grid is a group of interconnected loads and DERs within a clearly defined electrical  and geographical boundaries witch acts as a single controllable entity with respect to the main grid.

Literally, MG is defined as a system that consisting of renewable sources, small in size, and mainly locally available distributed or centralized renewable sources integrated system called Microgrid. 

when this system controlled by smart control strategies such as MNC converter, ICT-based control that can be dispatched automatically comply the market price, and demand called smart grid or smart microgrid.

recently Alborg University, Arizona state university, and the University of California, Berkeley has their own lab research center and research more about DC microgrid, and feasibility test in DC smart microgrid. such as Submarine DC grid, remotely located microgrid. 

when we introduced some Multilevel Converter, Advanced meter, and controlling center which can help smartly control 

Hello Masoud Zebarjadi ,

The phrase microgrid refers to the size of the grid from MVA capacity, and geographical extent points of view. As the name implies, it is a micro grid. On the other hand, a smart grid may be of any scale and any geographical extent while extensive use of advanced monitoring and control based communication technologies are embedded in the structure of smart grids. In addition, advanced IT technologies are used in such grids.

microgrid(lessthan 100kw) is an integral part of smart Grid..

micro grid(Extremely small grid with Distribution generation of rating less than 100kw)

where as smart grid is a grid with intelligence where it has the compatibility with Renewable Resources(Distribution Generation)

A difference is mainly the scale.

Smart grid is more intelligent than the Microgrid. I mean it is created with more advanced technology.

1. The smart grid exists in every scale and geographical location.

2. The smart grid extensively the use of advanced monitoring and control based communication technologies.

3. A microgrid (AC/DC) is an electrical system that includes multiple loads and distributed energy resources.

4. A microgrid (AC/DC) can also be a smart grid.

The smart grid is fully automatized using ICT technology for communication and automatic monitoring, control and protection with advanced technologies.

Microgrid (AC/DC) ai well explained above!