Modeling and Synchronization Stability of Low-Voltage Active Distribution Networks With Large-Scale Distributed Generations.

With the large-scale penetration of demand-side distributed generations (DG), the conventional low-voltage distribution network is becoming increasingly complex in the terms of synchronization stability and control. This paper presents the evolution process of energy transfer topology in the mathematical model, analyzes the network model and the synchronization stability of large-scale DGs in a low-voltage active distribution network. Topological mathematical models are established as the object to research incorporate DGs into three networks (i.e., star-shaped, circle-shaped, and tree-shaped networks) without changing the network architecture. Based on the Kuramoto oscillator form from a complex network theory perspective, the large-scale DGs with the frequency-droop controllers in the network can be transformed into a generalized Kuramoto model. Accordingly, by comparing the above proposed models with the standard networks (i.e., fully coupled network, NW small world network, and BA scale-free network), we discuss the synchronization stability for different topology structures of an active distributed network. The effectiveness and the superiority of the proposed topology structure are further demonstrated through numerical simulation methods, including frequency stability, phase stability, order parameters, and spectrum analysis. Furthermore, the improvement of Iceland 189-node grid is employed to prove the better stability with the star-shaped connection.