Enhancement of microgrid dynamic voltage stabilty using Microgrid Voltage Stabilizer

The microgrid concept has the potential to solve major problems arising from large penetration of distributed generation in distribution systems. A microgrid is not a robust system when compared to a power system. Therefore, proper control strategies should be implemented for a successful operation of a microgrid. This paper proposes the use of a coordinated control of reactive sources for the improvement of the dynamic voltage stability in a microgrid. The associated controller is termed as a Micro Grid Voltage Stabilizer (MGVS). The MGVS is a secondary level voltage controller which takes the weighted average of the voltage deficiencies at the load Buses and generates a control signal. This control signal is divided among the reactive power sources in the microgrid in proportion to their available capacities; thus each source will be required to generate certain amount of reactive power. The MGVS is implemented in a micro grid test system in MATLAB environment. A dynamic simulation of the test system is carried out for the cases of with and without the MGVS for various disturbances. Both grid-connected and islanded modes of operation are considered. Results show that, with the addition of MGVS, the dynamic voltage profile of the microgrid system, especially at the load Buses, improve drastically.