Adaptive Cognitive Compensation for Four-Wire Distribution Grids Using Disturbance-Aware UPQC-SPV Architecture

Abstract

The increasing penetration of renewable energy sources and nonlinear loads in modern distribution grids has 
intensified power quality challenges, including voltage sags/swells, harmonic distortion, load unbalance, and 
neutral current issues. Conventional Unified Power Quality Conditioners (UPQCs) operate with static control 
strategies, applying uniform compensation regardless of disturbance type resulting in suboptimal performance and 
unnecessary power losses. This paper proposes an Adaptive Cognitive Compensation (ACC) architecture that 
integrates a four-wire UPQC with a dual-stage Solar Photovoltaic (SPV) array with a disturbance-aware decision 
engine. The system employs a rule-based strategy mapper that dynamically selects between series-dominant, shunt
dominant, and hybrid compensation modes based on real-time classified disturbance type and severity. The 
theoretical advantages include reduced switching losses through selective inverter activation, faster response time 
via pre-configured mode selection, and maintained compliance with IEEE 519-2022 and IEEE 1159-2019 
standards. A comprehensive evaluation methodology is proposed using OPAL-RT real-time simulation, with test 
conditions, metrics, baselines, and hypotheses explicitly defined as open empirical questions. The mode-switching 
logic is justified through a categorical allocation framework where voltage-domain disturbances receive high series 
utilization, current-domain disturbances receive high shunt utilization, and combined disturbances receive hybrid 
compensation. This work provides a complete architectural blueprint and reproducible evaluation framework for 
future implementation and validation, representing a paradigm shift from static, reactive compensation to dynamic, 
cognitive power quality governance.