Two-Layer Distributed Control for Optimal Power Allocation in Islanded Networked Microgrids

Multiple microgrids can be interconnected as networked microgrids (NMGs) to improve the system resilience and economics. A proper and flexible economic control scheme for NMG system is of significance. This paper proposes a two-layer distributed control strategy, consisting of the low-layer control and upper-layer control, to achieve real-time optimal power allocation and maintain frequency and voltage stability. The low-layer control autonomously achieves optimal power allocation among distributed generators (DGs), and each DG provides frequency and voltage support by eliminating the error with upper-layer references. The upper-layer control realizes system frequency restoration, voltage restoration of common bus and real-time optimal power allocation among MGs by designing the MG equivalent cost functions. The designed distributed control scheme avoids the heavy computation burden as compared with static power allocation methods and thus offers more reliability. Lastly, the effectiveness of the proposed control framework is verified by the time-domain test based on MATLAB/Simulink platform.