Correlation Analysis between Shading Analysis and Power Output in a Photovoltaic System

Abstract

A photovoltaic (PV) string consists of PV modules that are connected in series. When partial shading occurs in the PV modules, the total PV string current is lowered. When the partial shading becomes severe, the bypass diode operates. Most PV systems are exposed to partial shading by nearby terrain, rather than an actual shaded flat environment. In this study, shading analysis was performed at 19 points of a 33.2 kWp solar power plant installed on the roof of a building, and the shaded irradiance ratio at the PV module location was estimated using this result. We compared the results of the performance ratio monitored for one year. As a result, the expected output ratio of the shading analysis compared to normal was found to be 89.6%, and the annual performance ratio was 90.2%.