A VOLTAGE STABILIZER FOR A MICROGRID SYSTEM WITH TWO TYPES OF DISTRIBUTED GENERATION RESOURCES

Microgrids are used as controllable units connected to power grid, in which the electrical distances between reactive power sources and the loads that need the reactive compensation are small. Thus, a coordinated compensation of reactive sources has to be implemented to avoid a fast voltage collapse by proposing a Microgrid Voltage Stabilizer (MGVS). This stabilizer is desirable to improve the dynamic voltage profile and is tested at a 21-bus IEEE microgrid system. In order to verify the performance of this stabilizer, three distributed generation (DG) resources are utilized in this microgrid (Two PV resources which are categorized as power-electronic converter based on DG and a diesel generator which is known as synchronous machine also based on DG). At first, the mentioned resources and all of their needed equipments are modeled. Then, a control model of the stabilizer with appropriate parameters for the proposed microgrid is presented. Voltage deficiency of the system is the input of the stabilizer, and the output signal of the stabilizer is divided between the DGs in order to provide required reactive power. The dynamic voltage profile of buses in the presence of MGVS and its absence has been compared by implying disturbances. Simulation results in MATLAB/SIMULINK show that the dynamic voltage profile of the buses improves satisfactorily with the addition of MGVS.