Impedance-Based Stability Analysis of Systems with the Dominant Presence of Distributed Power Sources

In recently developed electric power systems, numerous distributed generators (DGs) are connected via power electronic devices. Because these devices can generate harmonics and nonlinear distortion, traditional model-based approaches can become too complex to accurately analyze the dynamic responses of DGs. Stability analysis methods based on impedance scanning provide a practical alternative to the linear model approximation method; they directly measure the impedance of the source-load subsystems and evaluate the stability. However, most previous research focused on the characteristics of individual grid-connected devices and the stability of the microgrid (MG). In this study, the dynamic characteristics of a large-scale power system with intermittencies caused by the introduction of a large number of DGs with advanced inverter controls were analyzed through impedance-based analysis. The effect of the capacitance of passive filters and transmission lines in advanced DGs on stability was also investigated.