Assessing the Value of Reactive Power Injection from Photovoltaic Generation in Optimal Sizing Studies

The transition toward a sustainable society requires the large-scale integration of renewable energy resources into modern power systems. Among the available technologies, photovoltaic distributed generation (PDG) plays a key role in achieving these goals. This paper proposes an optimization model for the sizing of PDG in rural distribution systems (DSs). The active power contribution of PDG reduces the loading of the DS, while reactive power injection through Volt–VAR control improves the voltage profile. The optimization problem incorporates probabilistic constraints associated with voltage regulation, line ampacity, and reverse power flow at the substation. The proposed methodology, based on the enhanced snow geese algorithm (ESGA), was validated using two rural DSs with 95 and 170 buses. For the 95-bus system, the results demonstrated a significant improvement in the voltage profile and a 22.9% reduction in the annual energy supplied by the substation. For the 170-bus system, ESGA achieved a high-quality solution with an objective function value only 1.4% higher than that obtained by PSO. The resulting PV penetration levels reached 27.3% and 30.8%, respectively. These results demonstrate the capability of ESGA to provide solutions comparable to those obtained with well-established optimization techniques.