Investigation of the effects of microgrids on power system stability

Conventional power systems are faced with many problems, such as the reduction of fossil fuel resources, bad energy policies and environmental pollution. In addition, ever-increasing electric power demands are forcing power networks to work at load limits and make it difficult to transfer energy from central production points to energy consumption centers. These problems have led to a greater use of renewable energy sources and a new trend of regional power generation at the distribution voltage level. The microgrid concept has provided an interesting alternative for the power systems to overcome the challenges of integrating distributed energy sources, including renewable energy sources. The microgrid concept can be described as a cluster of micro-sources, storage systems and loads which present itself to the grid as a single entity that can respond to central control signals. Today, studies about the microgrid concept are increasing day by day. In this study, integration of microgrids into power systems and its effect on the stability of power system are investigated. Firstly, information about micro grid, power system stability classes and power system stability analysis methods are given. For the analysis studies, firstly a microgrid model was simulated and the appropriate place where this microgrid would be placed in the power system was determined. Then the effects of the microgrid installed in the power system on the stability of the power system are analyzed. In order to demonstrate the effect of the microgrid on the power system stability, power flow analysis, bifurcation analysis, small signal stability analysis, modal analysis and time domain simulation analysis studies have been carried out for the power system with microgrid and without microgrid. In all the stability analysis results, it is obtained that microgrid addition to the power system which has no microgrid has improved the stability of the power system.