Defect Detection and Degradation Analysis in Photovoltaic Modules using Thermography, Spectroscopy, and Current-Voltage Measurements, and Quantitative Assessment of Their Impact

摘要

The measurement of defects in photovoltaic (PV) module and their impact assessment can help to improve the reliability and performance of PV systems. Herein, improved defect detection and degradation analysis approach using the combination of infrared (IR) thermography, electroluminescence emission spectroscopy, and current-voltage (I-V) measurements are presented. Moreover, an image-processing scheme to automatically detect and compute defective area is also proposed. First, experiments are conducted on normal operating modules. Subsequently, different defects and failures are induced, and experiments are conducted again. These modules are analyzed quantitatively and qualitatively. From IR images, defective area, overheating, and underheating computations are carried out. From I-V measurements, power losses, current degradation, and voltage degradation calculations are carried out. The defects that show up in IR images are correlated with I-V curve deviations and their effect on power losses and current/voltage degradation is also analyzed. Moreover, electroluminescence emissions of defective regions are correlated with overheating/underheating calculations. Finally, the observations from experimental results and related quantitative/qualitative computations are summarized. This approach can help to investigate module degradation stage and mode. It can also help in decision making with the use of only IR imaging and related computations in absence of optimum measurement conditions.