Inverter-based resources (IBRs) are integral parts of modern power systems, facilitating the integration of renewable energy sources into the grid. These resources support critical functionalities such as grid-forming, grid-following, and grid-supporting operations, enabling seamless transitions between grid-connected and islanded modes of operation.
To analyze and study the performance of modern power systems, employing appropriate models for these inverter-based resources is necessary.
Power systems primarily operate under slow dynamic conditions, with transient or fast dynamics occurring only during brief periods, such as fault events, sudden load changes, or switching operations. During these slow dynamics, simplified models can effectively represent the system. Consequently, steady-state models are widely applied for load-flow analysis, energy management, and various other operational studies of power systems.
This paper presents a data-driven methodology for fitting a Thevenin circuit model to a grid-forming inverter interfacing a PEM fuel cell system with a microgrid. The model parameters are estimated using operational data obtained from the grid-forming resource. The proposed model is applicable to load-flow analysis and energy management during both the design and operational stages of power systems, supporting both online and offline applications. The reduced-complexity nature of the model minimizes computational demands, making it highly suitable for a range of applications, including optimal sizing of system components, grid planning, load-flow studies, steady-state stability analysis, feasibility assessments, optimal dispatch, and resource allocation. By providing a simplified yet effective representation, the model facilitates energy flow study in microgrids and power systems.