Voltage and Frequency Recovery in an Islanded Inverter-Based Microgrid Considering Load Type and Power Factor

Abstract

This paper introduces simple and complete under voltage-frequency load shedding schemes to determine proper load shedding amounts (LSAs) in an islanded inverter-based microgrids (IBMGs) considering power and power factor (PF) of various load types, such as constant power, constant current, and constant impedance loads. The proposed method employs a fast time-step simulation approach based on the complete state-space model of IBMG in order to obtain the transient and steady state responses of the system. The required power-voltage curves are obtained considering load PF and system topology. Ultimately, LSA is obtained according to the under voltage load shedding (LS) and under frequency LS values. To demonstrate the effectiveness of the proposed simple and complete LS methods, the corresponding performances are analyzed in a test islanded IBMG modeled in MATLAB. The simulation results show that unlike the other compared methods, the proposed LS approach can accurately determine less LSA while maintaining the power system stability.