Experimental Comparison of Visual Inspection and Infrared Thermography for the Detection of Soling and Partial Shading in Photovoltaic Arrays

Soling and partial shading of solar panels are two of the most common conditions that affects the power yield of a photovoltaic (PV) installation. Even though human inspection can easily identify such situations, in the case of large power plants covering thousands of hectares it is not practical. In this regard, unmanned areal systems (UAS) represents a useful tool to gather images in a short time for the inspection of thousands of PV panels. Using RGB and infrared cameras, UAS can be used to perform visual inspection (VI) and infrared thermography (IRT) to detect failures in PV arrays. The present paper presents the results of an experiment designed to evaluate the effectiveness of VI and IRT for detecting soiling and partial shadowing. It has been found that for the aforementioned conditions VI are more effective. Also, the methodology presented can be used as a reference for future research for other techniques and other failures. The results provide technical-scientific information for those in charge of operation and maintenance to make an objective choice of failure detection techniques.