Power Quality in Grid-Connected Photovoltaic Inverters: A Systematic Review of Critical Parameters, Standards, and Mitigation Strategies

The rapid integration of grid-connected photovoltaic (PV) systems has intensified concerns regarding power quality (PQ) driven by the widespread deployment of power electronic inverters and the increasing intermittency of operating environmental conditions. In this context, a comprehensive characterization of the critical PQ quantities and disturbance phenomena, applicable international standards, and performance of mitigation strategies is necessary to support reliable grid interoperability. This study presents a systematic literature review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and structured using the Population, Intervention, Comparison, and Outcome (PICO) framework to identify and critically synthesize recent peer-reviewed contributions published between 2020 and 2025. The review indicates that current total harmonic distortion (THDI), voltage total harmonic distortion (THDV), power factor (PF), voltage sag events, and voltage unbalance are among the most frequently addressed PQ quantities and phenomena, whereas other power quality aspects are assessed less consistently. This review compares the regulatory limits adopted worldwide, highlighting methodological variability across studies. In addition, it classifies recent control and mitigation techniques, including active filtering, advanced modulation, and adaptive control schemes, to improve the PQ performance and provide ancillary grid support. This study offers a structured mapping of the evaluated parameters, regulatory reference frameworks, and mitigation approaches, providing a consolidated basis for future research, standard harmonization, and the design of grid-connected PV inverter systems that comply with applicable requirements.