<p>Unified power quality conditioners (UPQCs) are considered one of the best methods for enhancing distribution networks’ power quality by reducing the effects of voltage fluctuations, harmonics, and sudden load changes. The system may experience quality problems when renewable energy sources (RES) and loads are integrated. Thus, in order to improve the quality of power in grid-connected systems, this paper proposes a novel pelican optimization algorithm (POA)-tuned cascaded controller to enhance the power quality in RES-integrated grid systems. The UPQC is employed to mitigate power quality issues like voltage sag, swell, and harmonic distortion caused by dynamic and nonlinear loads. A controller utilizes a fractional order proportional resonant and proportional integral controller (FOPR-PI) to address the power quality issues, which ensures precise voltage and current control. The gain parameters of these FOPR-PI controllers are optimized by using the Pelican optimization algorithm (POA). The proposed controller is implemented in a PV and wind-integrated microgrid with the help of MATLAB/Simulink. The results of the proposed approach are evaluated using various scenarios and a total harmonic distortions (THD) analysis. Additionally, the THD for the proposed method is calculated and compared to conventional methods. In comparison with the existing controllers, the proposed method yields a very low THD of 0.25%.</p>