Power Quality Enhancement in Renewable-Integrated Smart Grids Using Unified Power Quality Conditioners: A Review

Abstract

Over the last few decades, renewable energy sources gained significant attention that still continues today. Whether it be for solar or wind energy, conventional analyses considered these as intermittent sources of power, causing several power-quality issues in the respective power systems, such as harmonics, voltage distortion, or stability. The UPQC has extremely convenient features, and so, it is considered a suitable custom power device offering mitigation for these disturbances; however, conventional setups of a UPQC cannot sufficiently remain adaptable under intermittency of the renewable source. Recently, major research has been directed to modifying UPQC configurations through the injection of distributed generation (DG) sources for renewable applications, mainly solar PV and wind energy, at the DC common link. This review paper attempts to discuss in detail the above-mentioned modifications with respect to their contributions for DC link voltage support, harmonic mitigation, load compensation, and overall system efficiency. A critical evaluation concerning the control strategies for series and shunt converters is conducted in terms of their application toward hybrid renewable-based UPQC systems. Afterwards, a comparative study on the investigated approaches is given with regard to their advantages and disadvantages, as well as current technological trends. Among others, this review identifies a few key research gaps regarding scalability, dynamic performance, and real-time implementation and discusses the future perspectives that appear promising toward designing robust and energy-efficient UPQC architectures for smart grid applications.