A Comprehensive Control Strategy for F-SOP Considering Three-Phase Imbalance and Economic Operation in ISLDN

With the increasing integration of renewable energy sources (RES) and single-phase loads, three-phase imbalance and transformer lightly/heavily loaded operation issues has become more prominent in low-voltage distribution networks (LDN). However, existing research on interconnected systems of LDN (ISLDN) rarely addresses the comprehensive management of both three-phase imbalance and lightly/heavily loaded operation issues. To this end, a comprehensive control strategy for three-phase imbalance and lightly/heavily loaded operation in ISLDN based on a four-leg soft open point (F-SOP) is proposed in this paper. Firstly, the comprehensive loss characteristics model of ISLDN including the F-SOP and the transformer are established, revealing that both imbalance and load rate can affect the equipment efficiency. Secondly, considering the objective of minimizing power loss, an optimization dispatch strategy with constraints of three-phase imbalance and the optimal economic operation area is proposed to obtain the dispatch power commands for the F-SOP. Furthermore, an improved peer-to-peer control for F-SOP is proposed to ensure the conduct of the optimization dispatch strategy and enhance stability performance of system. Finally, the effectiveness and feasibility of the proposed comprehensive control strategy are validated by the simulations and experiments. The results show that comprehensive control of lightly/heavily loaded operation and three-phase imbalance in the ISLDN can significantly reduce daily power loss by 62%, improving system operation reliability and economy.