Impedance Modeling Method Considering the Phase of the Grid Connection Point in Grid-Forming and Grid-Following Converter Multi-Machine System

In recent years, the rapid growth of renewable energy sources such as wind and solar power has contributed to environmental improvements while introducing new challenges to the safe and stable operation of power systems. Impedance-based methods are widely used for small-signal stability analysis; however, conventional modeling approaches that neglect the grid connection point phase are increasingly inadequate as research on inverters advances. This paper presents a novel modeling method that accounts for the phase of the grid connection point. By incorporating the grid connection phase in the derivation process, the proposed approach ensures applicability even when the inverter phase is not constant. The method is applied to the grid-forming and grid-following converter multi-machine systems to investigate factors influencing its stability, thereby demonstrating the method's versatility and general applicability.