Evolution of Microgrid and Hierarchical Control of Microgrid

A microgrid is a local energy grid with control capability, which means it can disconnect from the traditional grid and operate autonomously. Our survey on this topic, focuses on the proposed technical control solutions for the various levels of the Microgrid organization hierarchy. An electric grid is an interconnected network where electricity is delivered from producers to consumers. Grids vary in sizes and consist of: power stations, electrical substations, electric power transmission and electric power distribution. The difference between a traditional grid and a microgrid can be clarified using an example: in a traditional system, if the power transmission source and load are out of balance, the power is instantly balanced by the system's rotational inertia, modifying the intensity, which is the simple concept of the P-f droop control method. The microgrid, on the other hand, lacks inertia because most of the microgrid's sources are renewable , making the microgrid control system architecture complex and difficult. This resulted in the development of a new control technique for microgrids called Hierarchical Control (HC), which has three levels: main control, secondary control, and tertiary. According to our research, as of 2021, about a billion individuals distributed across various places were unable to connect to the power grid due to a variety of issues, the most significant of which was difficult economic conditions. Our survey mainly mentions how the complicated grid structure is a source of particular worry, and that microgrids were established to address this issue. Electric grids are vulnerable to malicious attack and cyber threats nowadays, thus their security is a must. They are enormous in size and are frequently found far from densely populated areas.