# Case Study of Power Plants in the Slovak Republic and Construction of Microgrid and Smart Grid
## 3 Microgrid  
Research shows microgrid systems will be a key part of building smart grids, and this major part also provides solutions for powering remote communities and industrial facilities and military bases that are usually connected to the grid so that they can disconnect and operate independently. Microgrid working system:  
* On-grid microgrid obtains a battery-free system that is connected to the public power grid. Any excess solar energy they produce is provided in the power grid. The primary disadvantage of this structure is that they fail to operate during a blackout [26]. * Off-grid microgrids typically provide power for remote villages, industrial operations, and military bases. These usually have a very high cost of generation as they are totally dependent on diesel fuel and may face logistical challenges in fuel delivery. We can also use photovoltaic panels with battery systems, but in this case, we have certain performance limitations [26]. * Hybrid microgrids can be disconnected from the grid to operate autonomously, ensuring continuity of power supply in the case of an outage. This approach is common in locations where the grid can be unreliable, such as storm-prone or mountainous areas. As shown in Figure 6 system takes advantage of both previous systems. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Energy Source** & **Western Slovakia** & **Middle Slovakia** & **Eastern Slovakia** \\ \hline Nuclear & 1950 MW & 0 MW & 0 MW \\ Hydro & 1166.2 MW & 1289.98 MW & 111.19 MW \\ Hard coal & 0 MW & 0 MW & 220 MW \\ Lignite & 220 MW & 81.77 MW & 0 MW \\ Natural gas & 903.3 MW & 18.9 MW & 170.5 MW \\ Oil & 45.9 MW & 32 MW & 0.72 MW \\ Mix fuels & 46 MW & 35 MW & 320.5 MW \\ Solar & 130.39 MW & 231.32 MW & 128.54 MW \\ Biomass & 43.67 MW & 56.78 MW & 52.39 MW \\ Biofuel & 44.41 MW & 33.65 MW & 24.82 MW \\ Wind & 3.14 MW & 0 MW & 0 MW \\ Other RES & 4.66 MW & 0 MW & 0 MW \\ Other & 6.3 MW & 0 MW & 6 MW \\ Total & 4563.46 MW & 1779.39 MW & 1034.66 MW \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Division of power plants in Slovakia [20, 21, 22, 23, 24, 25]. Figure 5: Division of power plans in Slovakia [20, 21, 22, 23, 24, 25]. The most promising for the future is a hybrid system, which, as shown in Figure 6, uses the advantages of both the On-grid and the Off-grid systems. However, there are also problems with this system in the form of a protection system and locating faults. The main problem with the microgrid system is the way of managing individual resources so that they work as efficiently as viable and with the least possible losses. Solving these problems in microgrid systems will simplify management, increase the efficiency of electricity generation, and reduce transmission losses in the smart grid. For these microgrid systems, it will therefore be essential to select, according to the area of application, the appropriate energy sources so that the supply of electricity is guaranteed under any weather conditions. The problem with applying these structures in practice is several, but the essential problems are with a suitable mix of energy sources for such systems and the transmission infrastructure itself, which is undesigned for such changes. The key will be to determine the size of the area that such a microgrid system will control. Examples of Application of Microgrid Systems  
The schematic of the microgrid system shown in Figure 6 has already been practically tested on island operation and is currently working in a few places. One such system supplies electricity to the remote north of the Arctic, with approximately 160 members of Lake Colville located 50 km beyond the Arctic Circle in Northern Canada.