Control strategy evaluation for reactive power management in grid-connected photovoltaic systems under varying solar conditions

Solar energy is environmentally friendly and one of the most significant renewable energy sources. This energy is a leading renewable energy source, contributing significantly to sustainable development goals. In grid-connected photovoltaic (PV) systems, reactive power management is essential for maintaining voltage stability and ensuring reliable operation. However, the influence of fluctuating solar irradiation (G) on reactive power (Q) behavior is often underrepresented in conventional inverter control strategies. This research addresses this gap by modeling the dependence of reactive power on solar irradiance using a data-driven curve-fitting approach. The methodology involves the acquisition of real-world operational data, preprocessing, selection of an appropriate analytical model, and validation of its performance. The findings indicate that reactive power increases under low irradiance conditions, primarily due to inverter behavior and grid voltage support requirements. The resulting analytical expression offers a practical framework for integrating irradiance-dependent reactive power control into inverter firmware or grid management software. The model performed with high accuracy with an R2 of 0.9955. This contribution enhances the ability of PV systems to respond dynamically to environmental changes, improving grid compatibility, operational efficiency, and voltage regulation in modern distributed energy networks.