Safe trajectory sets for online operation of power systems under uncertainty

Flexibility provision from active distribution grids requires efficient and robust methods of optimization and control suitable for online operation. In this paper we introduce conditions for the secure operation of power systems using feedback optimization based controllers. The feasibility of system operation is defined using the Feasible Operating Region (FOR), which serves as a boundary for safe system states. We propose a method to compute safe trajectory sets by projecting the high-dimensional system state onto the two-dimensional PQ-plane, enabling intuitive analysis of controller behavior. Our method is demonstrated on an exemplary sub-transmission system, where we evaluate the controller's performance and robustness under disturbances and uncertainties. Results highlight the suitability of the proposed approach for assessing reachable and feasible system states in cases where the controlled grid is subjected to disturbances.