Novel Topological Aggregation Method for Grid-Forming Converters of Renewable Energy with Threshold Correction

With the increasing integration of renewable energy sources into modern power grids, the dynamic and operational complexity of power systems has grown significantly, rendering traditional control and modeling approaches insufficient. Virtual Synchronous Generator (VSG) technology has emerged as a critical solution, replicating the dynamics of synchronous generators to enhance the stability of inverter-based systems. Aggregation of VSG units is essential for efficient modeling and analysis of large-scale systems, especially in addressing challenges like power oscillations, dynamic stability, and control interactions. This paper proposes an improved homological equivalent method tailored for VSGs, incorporating a precise definition of critical parameters such as the time window and threshold to enhance its applicability. Additionally, aggregation methods for VSG control and circuit parameters are developed to facilitate the representation of complex systems. The proposed methods are validated through Matlab/Simulink simulations, where the performance of the aggregated VSG model is compared with the original VSG group. Results confirm the reliability and effectiveness of the approach in retaining dynamic characteristics while reducing modeling complexity. This research provides a theoretical foundation and practical methodology for VSG aggregation, contributing to enhanced stability analysis and operational efficiency in high-renewable-penetration power systems.