Optimizing Grid-Connected Solar Power for Steady-State Operation with PSO-Tuned UPFC

The increasing penetration of renewable energy into distribution systems or networks createsvoltage instability, high power losses, oscillatory disturbances, and harmonic distortion. Thisstudy applies a Particle Swarm Optimization (PSO)-tuned Unified Power Flow Controller(UPFC) to a power distribution network to mitigate instability caused by 5 MW solarpenetration. MATLAB/Simulink was employed to simulate three operating scenarios: normaloperation without renewable integration, solar photovoltaic (PV) integration without control,and solar PV integration with PSO-UPFC compensation. Results show that the PSO-UPFCmaintained a stable bus voltage profile close to 1.0 p.u., even at the peak load of 7.9 MW.Power losses were reduced by approximately 55% compared to the uncontrolled solar scenario,demonstrating significant efficiency improvement. Oscillation magnitudes were damped bynearly 90%, ensuring faster system settling and improved dynamic stability. Total harmonicdistortion (THD) was reduced by 80% compared to the uncontrolled solar case, indicatingenhanced waveform quality and improved equipment protection. The PSO algorithm achievedrapid convergence, reaching an optimal fitness value of approximately 0.05 within 100iterations, confirming the effectiveness of the optimization strategy. The findings support theadoption of UPFC to enforce grid codes, enhance voltage compliance, reduce energy losses,and improve power quality.