Anotace:
The growing use of advanced equipment in modern systems, such as electronic devices and drives, has led to a decline in power quality (PQ), causing malfunctions in sensitive loads. Additionally, the integration of renewable energy sources into the power grid significantly impacts the PQ of the electrical system. To address these effects on voltage stability and harmonic distortion, the unified power flow controller (UPFC) series compensator has proven to be a highly effective solution. This study focuses on using the UPFC to mitigate PQ issues related to renewables, including voltage sag, swell, harmonics, and fault conditions. The UPFC is controlled by a fractional order proportional integral derivative (FOPID) controller, which uses the improved zebra optimization algorithm (ZOA) to determine optimal gain values under various PQ scenarios. Furthermore, three comparative assessments of different optimization approaches are conducted to achieve the desired performance and power of the proposed UPFC. The results showed that the proposed ZOA approach compared with WOA and PSO yielded the shortest computing time of 173.554, 257.544, and 382.405 seconds and achieved an objective function value of 2.371, 2.387, and 2.398, respectively. The effectiveness of the proposed strategy is validated using the MATLAB/Simulink platform, with results showing significant improvements in voltage stability and harmonic reduction.