Dynamic Modeling of Active Distribution Networks Using the Aggregate Parameterized DER-A Model for Voltage Stability Studies

The integration of distributed energy resources into active distribution networks (ADNs) has created a need for accurate dynamic models to be used in stability and planning studies. Aggregated models, such as the DER-A model, provide a practical method for representing the collective behavior of inverter-based generators (IBGs) at the feeder level. However, the process of parameterizing these models presents a significant challenge, particularly under changing operating conditions and real-time constraints. This paper proposes an online methodology for parameter estimation of the DER-A model using moving horizon estimation. The objective is to identify the parameters governing voltage stability, critical for maintaining reliable grid operations in ADNs. The methodology incorporates a smooth mathematical representation of the DER-A model, which enable robust estimation under noisy measurements conditions and system disturbances. Simulation results validate the proposed approach, demonstrating its capability to accurately capture the dynamic behavior of aggregated IBGs under different levels of penetration and disturbances.