Advancement in Techniques towards Optimal Operation of UPQC for Power Quality Improvement

The advantages of RES for the environment have made them commercially viable and widely used today. The microgrid is also crucial to conventional power distribution systems due to its improved dependability and reduced overall energy losses. For more adaptability, renewable energy sources (RES) including solar, wind, batteries, fuel, tidal, etc., satisfy massive power demands based on dispersed generation and non-linear loads, which may result in power quality problems like voltage sag/swell and harmonic distortion. Many power-conditioning types of equipment are used to solve PQ issues. Among them, UPQC acts as the most significant choice for reducing PQ issues. As a result, a literature review was conducted in this research, using the 30 most significant research publications from IEEE, Science Direct, and Springer journals. These contirbutuons were all compiled between the years 2010 and 2021. This study has examined 30 academic research contributions in several ways, including from the perspectives of optimization algorithms and AI-based control strategies, to get an understanding of what are all about. Additionally, each work's performance under sag/swell conditions is demonstrated in terms of voltage, current, and THD. Furthermore, the present challenges in UPQC power quality enhancement methods for distributed generators connected to the grid will be described, which will be a significant milestone for researchers in the future.