Combined central-local voltage control of inverter-based DG in active distribution networks

The increased integration of distributed generators (DGs) has exacerbated voltage violations in active distribution networks (ADNs). Utilizing the var capacity offered by DG inverters presents a potential solution for managing the voltage of ADN. By merging the merits of different hierarchies, the combined voltage control can provide better performances in addressing the variability of DGs. In this paper, a combined central-local voltage control strategy is proposed for DGs to suppress voltage fluctuations. Firstly, the control strategy for DGs is generated for global optimization, considering the coordination of discrete regulation devices and DGs in a long-time scale. Then, the local control curve for DGs is established based on the reactive power value of DGs determined in the central strategy. To further enhance the robustness of the local control curves, a parameter tuning model for the local control curve is built based on the distributionally robust optimization (DRO) method. The voltage violations caused by DG fluctuations can be quickly suppressed by using the local control curve. Finally, the effectiveness of the combined central-local control strategy is substantiated through validation using both the modified IEEE 33-node distribution system and the practical JMF3 80-node distribution system. The proposed method can improve voltage control performance while enhancing the adaptation to DG fluctuation.