Analytical Methods for Inverter-Based Resources Stability

This technical report discusses analytical methods for determining the stable operation of inverter-based resources (IBRs) within future power systems, specifically focusing on small-signal stability. The report outlines the importance of understanding various stability aspects, including large signal, small signal, and voltage stability, as the share of IBRs increases in Australian power networks. It details the methodology for constructing small-signal models using linear models of individual devices and highlights the challenges posed by blackbox models provided by IBR manufacturers. The report presents findings from multiple project stages, including time series power flow analysis and the development of methods for estimating IBR admittance and impedance characteristics. It also addresses the impact of operating points on small-signal stability characteristics and proposes further research into evaluating stability margins and screening methods. The overall objective is to enhance the understanding of IBR behavior in dynamic conditions and improve the accuracy of stability assessments in the context of high IBR penetration.