SENSITIVITY ANALYSIS OF FREQUENCY AND VOLTAGE STABILITY IN ISLANDED MICROGRID

This paper studies the voltage and frequency stabil ity of an islanded microgrid and the sensitivity of these qua ntities to certain changes in system configuration. In convent ional power systems the system frequency is coupled with the rotor speed of the directly grid connected large synchronous generators and power unbalance can be s een as changed system frequency. But in an islanded mic rogrid it is possible that all generation units are connec ted to grid via converters and there is no inertia of rotating masses to affect the frequency. In that case the frequency ha s to be created by a power electronic device and the freque ncy is more of less fixed and power unbalance cannot be de tected in the classical way. The studied urban low voltage (LV) network based microgrid consists of three converter s and one synchronous generator based distributed generat ion (DG) units. The studies are made with PSCAD simulat ion software.