Performance Analysis of Grid-Connected Solar Photovoltaic Systems Under Variable Weather Conditions

Abstract

Grid-connected photovoltaic (PV) generation is strongly affected by short- and long-term variations in solar irradiance, ambient and module temperature, humidity, wind, cloud cover, and associated balance-of-system losses. This methodology paper presents a reproducible framework for quantifying how variable weather conditions influence the performance of a grid-connected PV system using normalized indicators commonly adopted in field studies. The proposed method combines time-synchronized meteorological and electrical measurements, data-quality screening, temperature-sensitive PV conversion modeling, and calculation of reference yield, final yield, performance ratio, capacity factor, and system efficiency. To demonstrate the workflow without claiming unavailable field measurements, an illustrative 100 kWp system is evaluated using a synthetic 2020 monthly weather profile representative of a warm subtropical site. The modeled annual AC energy is 140.78 MWh, with a final yield of 1407.8 kWh/kWp, an annual performance ratio of 76.6%, and a capacity factor of 16.0%. Performance is highest during cooler, clear months and deteriorates during hot or humid/cloudy periods despite comparable irradiance. The framework is suitable for comparative studies, preliminary plant diagnostics, and future validation with SCADA and on-site meteorological data.