Scientific African (Jul 2023)
Characterisation of visual defects on installed solar photovoltaic (PV) modules in different climatic zones in Ghana
Abstract
Visual defects on photovoltaic (PV) modules depend on climatic conditions and hence, vary from one country to another. This study characterised visual defects on PV modules installed in three climatic zones in Ghana and determined the link between the defective modules and output power degradation. It identified and classified these defects according to climatic zones and age groups of the modules. It also compared the degradation rates of the modules with visual defects and those without visual defects to determine the influence of the visual defects on output power degradation of the modules. The study used 104 PV modules of different technologies, which were older than 5 years, selected from 16 PV systems installed in the three climatic zones. A walkthrough visual inspection of the modules was performed to observe the visible defects, followed by current-voltage (I-V) curve tracing. The results revealed that encapsulant discoloration and corrosion of frames were found on 50% and 30% of the modules respectively. The other identified visual defects include encapsulant delamination, corrosion of metallisation, sealant infiltration, snail track and cracks in cells, which were few. Encapsulant discoloration was predominant in all the climatic zones and highest in Interior Savannah Climatic Zone while corrosion of frame was prevalent in Dry Equatorial Climatic Zone. The recently installed PV modules succumbed more to these defects than those installed years ago. Overall, modules with visual defects degraded at faster rates than those without visual defects, but the output power degradation could not be wholly attributed to these visual defects because some of the modules with severe visual defects degraded lesser than some of the modules with minor or no visual defects and vice versa. However, the visual defects provided initial clues about the degradation of the modules. Thus, regular visual inspection of the modules should be carried out for early identification of these defects to detect problems that could lead to failures in the future.
