A Regulation Method Considering Coupled Voltage Violation and Unbalance in Three-Phase Four-Wire Hybrid AC/DC LVDNs with High Penetration PVs

Low-voltage distribution networks (LVDNs) have witnessed an increasing penetration of distributed photovoltaics (PVs), which exacerbates the existing voltage violation and voltage unbalance issues. PVs, energy storage systems, and voltage source converters can regulate voltages in hybrid AC/DC LVDNs. To solve the above two voltage problems simultaneously, a partition-based coordinated regulation method is proposed in this paper considering the coupling of the two issues and the effect of active power on reactive power in electrical distance calculation. The voltage adjustments in different voltage violation scenarios are obtained based on a graph that describes the coupling of the two issues mathematically. In order to better determine control devices, the equivalent coefficient of active power adjustment on electrical distance calculation is considered in the partition method, in which regulation efficiency, regulation cost, and regulation capability are used as objectives. The coordination of controllable devices is achieved according to three-phase four-wire sensitivities. Case studies are performed to verify the effectiveness and accuracy of the proposed regulation method in hybrid AC/DC LVDNs.