Maintaining balance between generations and loads is an essential issue in power electronic-interfaced microgrids. Furthermore, due to inherent changing of operation mode from grid-connected to islanded, the risk of placing the microgrid in emergency condition is increased. Therefore, it is vital to recognize the emergency condition and implement an efficient approach, accordingly. This paper introduces a new algorithm for under voltage-frequency load shedding in AC microgrids. The proposed algorithm uses the system frequency, rate of change of the frequency, and voltage standard deviation parameters to identifying emergency condition properly at the right time and decrease the amount of load shedding to the least. The effectiveness of the proposed approach is evaluated through a typical microgrid test system.
