Impedance-Based Stability Analysis of Power Systems Incorporating Inverter-Based Resources: Techniques, Methods, and Applications

Analysis and control methods utilizing the impedance of power sources and loads have garnered attention for enhancing the fault tolerance of power systems. However, conducting actual impedance measurements across a wide bandwidth in the laboratory poses several challenges, including the accuracy of measured values and magnetic saturation of power transformers. Therefore, this study implements a microgrid (MG) in the laboratory, consisting of a power electronics converter controlled as a virtual synchronous machine (VSM) and a power emulator, to analyze the stability of the MG by measuring the actual impedances of the converter and the grid. Various MG conditions were simulated by changing the output of the power emulator and the control of the VSM, and the required perturbation amplitude and frequency bandwidth for impedance measurements were quantitatively determined, successfully establishing an analysis method.