Unified Control Scheme for Optimal Allocation of GFM and GFL Inverters in Power Networks

Abstract: With the rapid adoption of emerging inverter-based resources, it is crucial to understand their dynamic interactions across the network and ensure stability. This paper proposes a systematic and efficient method to determine the optimal allocation of grid-forming and grid-following inverters in power networks. The approach leverages a novel unified grid-forming/following inverter control and formulates an optimization problem to ensure stability and maximal energy dissipation during transient periods. An iterative algorithm is developed to solve the optimization problem. The resulting optimal droop gains for the unified inverters provide insights into the needs for grid-forming and grid-following resources in the network. A three-bus system is used to demonstrate the optimality and dynamic performance of the proposed method.