ORPD Enhancement Using TCSC and UPFC: A Kepler Optimization Algorithm-Based Approach with Single and Multi-Objective Benchmark

Abstract This work presents a new Optimal Reactive Power Dispatch (ORPD) scheme using single-objective and multi-objective optimization to achieve higher system performance under diverse operating conditions. Two different Flexible AC Transmission Systems (FACTS) devices, in particular the Thyristor-Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC), have been strategically implemented on the IEEE 30-bus and IEEE 118-bus test systems, enabling control of reactive power flows, enhancement of voltage stability, and reduction of transmission losses. The Kepler Optimization Algorithm (KOA) is chosen as the main optimization algorithm by virtue of its excellent global exploration ability, as well as strong convergence behavior for both single-objective and multi-objective formulations, as they are used for loss reduction, voltage deviation minimization, and stability margin enhancement. The performance of the proposed methods is also demonstrated with comparisons to existing metaheuristic methods like Bat Algorithm (BA), Grey Wolf Optimizer (GWO), Ant Lion Optimizer (ALO), Tabu Search (TS), Particle Swarm Optimization (PSO), Modified Ant Lion Optimizer (MALO), and Hybridized Tabu Search–Simulated Annealing (HTSSA). Through the simulation, the KOA proves to be consistently better compared to benchmark methods for single-objective and multi-objective ORPD scenarios, leading to significant reductions in real power losses, improvement of voltage profiles, and the provision of optimal trade-off solutions. The TCSC and UPFC are also incorporated to enhance the controllability and resilience of the system. This KOA-based ORPD approach is an adequate and scalable solution for modern power systems, needing advanced reactive power handling and multi-criteria operational optimization.