POWER FLOW ANALYSIS OF ISLANDED HYBRID AC/DC MICROGRID

Abstract

Presently, a lot of research is going on for power flow studies for better management of power flow among the sub-grids. With the changing times, the power requirement of the world is also increasing. Hence, the traditional power system also needs to change in order to fulfill the larger amount of demand and peak load. Consequently, a large number of distributed generation sources are connected to the grid to balance the demand. But, if this DG is connected without having autonomous control capability, it will create problems for the utility grid as well as the consumers. To overcome these problems microgrid is used to manage the distributed generation and cater to the load demand. A microgrid can be used to supply the power continuously for private buildings and the colleges, or the whole city, even in the situation when the main grid or surrounding microgrid enables to fulfil the demand, this makes the system more stable and efficient. Microgrids also can be a solution to reduce pollution and meet environmental objectives because connected sources are renewable and environmentally friendly. It is also useful in a critical situation when the main grid gets affected by weather or some fault happens in the system then the microgrid controls autonomously the supply and the demand of power The microgrid can be AC or DC in nature, Both AC and DC microgrids can balance the power and load demand individually. In cases where DC electronics loads are present and integrating renewable energy sources in the microgrid is required, the DC microgrid is the best option to choose. Moreover, where the system requirement is of step up and step-down voltage level and connected electronic loads are AC powered, then an AC microgrid is the preferable choice to go with. In the contemporary world, some power systems require the benefits of both AC and DC microgrids at the same time. In those cases, the hybrid microgrid can be very useful. If a hybrid microgrid operates autonomously then this power system becomes very complex to build because of the complexity of the power system. Moreover, load flow studies of the system become absolutely necessary before building such type of system. A hybrid microgrid is connected through different distributed energy resources like a solar panel, and wind turbine which is environmentally friendly. That’s why islanded microgrid's power flow studies are becoming increasingly significant for the researcher. Various methods have been proposed to study the power flow of microgrids but most of them are confined to only one system, either AC or DC microgrid systems. Therefore, a hybrid microgrid system's power flow analysis must be done separately.