Dynamic modeling of hybrid GFM-GFL distributed generators for enhanced transient stability based on phasor-domain control

The increasing demand for low-carbon resources drives the adoption of distributed energy resources (DERs) to shape sustainable cities. To ensure stable operation and cost-effective inverter deployment, microgrids (MGs) are equipped with grid-forming (GFM) and grid-following (GFL) units. This paper presents a strategic framework for planning and operating multiple DERs to enhance resilience in sustainable smart grids. A low-order phasor-domain dynamic model for systems with various DERs is developed, integrating GFM and GFL units in multi-DER islanded MGs to assess large-signal stability and optimize DER dispatch. The proposed equation facilitates optimal control allocation and strategic GFM placement to improve transient stability. A structured scenario-based search is employed to assess the critical clearing time for islanded MGs and to identify effective GFM location while accounting for DER interaction dynamics. Results highlight the crucial role of GFM placement in enhancing transient stability and operational resilience, with equivalent impedance between DERs significantly influencing the proposed model solution. Validation through single-city and multi-city networks demonstrates the robustness and effectiveness of the proposed strategy. This work provides a comprehensive solution for efficient DER control dispatch and strategic RES integration, offering valuable insights for advancing the resilience and sustainability of modern innovative grid systems. • to propose a nonlinear low-order phasor-domain dynamic model for multiple DGs. • to select the most suitable location for GFM to enhance transient stability. • to validate the proposed control approach by implementing PHIL verifications.