Investigation of the Accuracy of Thermographic Inspections of Photovoltaic Modules

Remote inspections of photovoltaic installations are an important factor for taking timely measures to increase their efficiency and reduce degradation. This study deals with the accuracy and uncertainty of thermal measurements of PV cells. An experiment is organized in order to compare the measured temperatures with means of contact sensor and contactless infrared cameras from different distance. The obtained results indicate significant difference in the measured peak temperatures with the different means. Furthermore, the temperature gradient of an affected cell depends strongly on the soiling area and could surpass $40^{\circ}\mathrm{C}$, which is a precondition for significant errors in the measured temperatures, i.e. it creates a significant uncertainty. Another important observation is that for the investigated polycrystalline module no hotspot was created if 6% or less of a cell’s area is covered.