Frequency-Constrained Optimal Restoration Scheduling in Active Distribution Networks With Dynamic Boundaries for Networked Microgrids

This paper proposes a frequency security-constrained optimal restoration scheduling framework for active distribution networks (FRSDN). The approach leverages distributed energy resources (DERs), particularly the inverter-interfaced renewable energy generators (IIREGs). First, incorporating the equivalent aggregated frequency response from both the governors of synchronous thermal generators (TGs) and the virtual synchronous control manner of IIREGs, linearized and conservative constraints for dynamic frequency metrics are derived, in particular for load-pickup process in renewable-based distribution system restoration (DSR). Next, a sequential dynamic boundary identification model (SDIDM) is developed to identify the dynamic boundaries and the involved generator types of networked microgrids (MGs), which facilitates the precise imposition of frequency security constraints by conserving the serial numbers of dynamically clustered networked MGs. Finally, the frequency-constrained DSR method is formulated as a three-layer robust mixed-integer linear programming (MILP) problem and solved by the column-and-constraint generation (C&CG) algorithm. Numerical results on a modified IEEE 123-node system are leveraged to demonstrate the effectiveness and superiorities of the proposed method. It is manifested that the frequency responses of all boundary-aware MGs could be confined to secure conditions by implementing the proposed FRSDN.