A Hybrid Scenario-Based Approach to Optimal Reactive Power Dispatch in renewable-rich distribution networks

The increasing integration of renewable energy sources (RES) into power systems introduces significant challenges in reactive power management and voltage regulation due to the inherent variability and uncertainty of renewable generation and load demand. This paper proposes an Optimal Reactive Power Dispatch (ORPD) framework that incorporates uncertainty modeling of wind speed, solar irradiance, and load variations using a hybrid scenario generation approach combined with Monte Carlo simulations. The BAT optimization algorithm is used to solve the nonlinear ORPD problem. The IEEE 5-bus test network is used as a case study to determine the optimal placement of FACTS devices and RES generation units with the objective of minimizing transmission power losses. Results demonstrate that the evolutionary BAT algorithm outperforms conventional deterministic methods, achieving significant reductions of 17.74% in power losses. The study identifies bus 3 as the optimal location for both wind and solar RES installations, while the strategic placement of a STATCOM FACTS device at bus 2 further reduces transmission losses by more than 4%. Incorporating uncertainty reveals an increase in expected transmission losses, emphasizing the importance of stochastic modeling in reactive power optimization. The proposed approach provides a practical and robust tool for power system operators to enhance grid reliability and efficiency in renewable-rich networks, supporting the transition toward sustainable energy systems.