Solar panel failure detection by infrared UAS digital photogrammetry: A case study

Infrared thermal photogrammetry is an attractive solution for the diagnosis of photovoltaic systems. Traditional systems often require high-end drones and expensive cameras, but more recently, low-cost thermal sensors on board of smallscale drone platforms suitable for digital photogrammetry have emerged as a promising approach. Nevertheless, studies evaluating its effectiveness can barely be found in the literature. Unlike many works in the literature that analyze individual images, through digital photogrammetry it is also possible to create orthomosaics of complete installations or high-resolution maps of segments that cannot be visualized and analyzed properly with single images. In this work, a photogrammetric thermal analysis methodology with a small-scale drone and a thermal camera is presented and a case of study is analyzed. To validate and quantitatively scale the results, functional tests on the panels were performed and temperature measurements with a thermocouple on the panels were carried out. The results from both single images and orthomosaics confirm that it is possible to obtain qualitative and quantitative information to detect failures in solar panel installations with a low-cost thermal sensor on board of small-scale drone platforms. These results may be useful for defining surveillance and maintenance procedures with low-cost equipment in photovoltaic installations, which can help for early detection of failures, operation with higher efficiency and to achieve longer lifetimes of the panels.