Simultaneous Planning of PV and DSTATCOM for Combined Mitigation of Voltage Deviation and Unbalance

The increased integration of photovoltaic systems (PVs) and unbalanced loads in low-voltage (LV) distribution systems has negative consequences on the overall performance of the utility grid (UG), resulting in voltage imbalance, power losses, line overheating, and various power quality issues. To enhance the hosting capacity (HC) of such distribution systems for accommodating increased capacities of PVs, the reactive power control (RPC) techniques, such as distribution static compensators (DSTATCOMs) are utilized to regulate voltage profiles and address voltage unbalances. In this regard, this study focuses on coordinating the sizing and placement of PVs and DSTATCOMs to mitigate voltage unbalances and maintain acceptable limits for other power quality metrics, particularly in unbalanced three-phase systems. By accounting for fluctuations in both load demand and solar irradiance, a multi-objective grey wolf optimization (MOGWO) algorithm verifies the planning method within the IEEE 123-bus unbalanced distribution system, employing the co-simulation between MATLAB and OpenDSS platforms. As a result of this proposed planning approach, voltage unbalances, power losses, and voltage deviations are reduced by 21%, 42%, and 23%, respectively, under 100% overloading conditions, alongside a 215% penetration level of PVs. Furthermore, the proposed planning strategy underscores that the combination of PVs and DSTATCOMs can alleviate voltage unbalances, consequently reducing power losses and thermal line overloading effectively.