Techno-Economic Multi-Objective Optimization of DG, Soft Open Points, and Demand Response for EV Integrated Distribution Networks

With the widespread proliferation of electric vehicle charging stations in the modern distribution networks, several operational challenges have emerged, including increased power losses, voltage instability, harmonic distortion, and higher substation loading. Conventional distribution systems were not originally designed to accommodate such dynamic and concentrated loads; therefore, coordinated planning, and advanced control strategies are essential to ensure reliable and efficient operation. In this paper proposes a comprehensive multi-objective optimization framework for the IEEE 33 bus radial distribution system; that integrates distributed generation (DG), soft open points (SOPs), and demand response (DR) in a coordinated manner. The proposed framework simultaneously addresses multiple technical and economic objectives, including minimization of power losses, enhancement of voltage profiles, reduction of harmonic distortion, and effective management of substation capacity. To achieve optimal placement and sizing of distributed resources under various operating scenarios, Harris Hawks Optimization (HHO) and Particle Swarm Optimization (PSO) are employed. The coordinated utilization of DG and SOPs significantly enhances power flow flexibility and voltage regulation, while demand response effectively reshapes load profiles and mitigates peak demand stress caused by electric vehicle charging station (EVCS). The results demonstrate that uncoordinated integration of EV charging infrastructure can substantially degrade network performance. In contrast, coordinated deployment of DG, SOPs, and DR leads to notable improvements in system efficiency, voltage stability, and power quality. Furthermore, HHO consistently outperforms PSO by providing superior convergence characteristics and more balanced trade-offs among competing objectives. Overall, the proposed multi-objective framework offers a robust and scalable solution for future smart distribution networks with high electric vehicle penetration, underscoring the critical role of coordinated resource planning and advanced optimization techniques in achieving safe, economical, and sustainable power system operation.