An infrared thermographic approach as a hot-spot detection tool for photovoltaic modules using image histogram and line profile analysis

As ecological awareness has intensified during the past two decades, renewable energy sources (RES) and, consequently, photovoltaic (PV) systems have undergone an impressively fast evolution. However, the sustainability of an installed PV system can only be achieved through its performance optimisation by reducing any source of fault, structural defect or malfunction during either the manufacturing or the operating (after installation) stage. This paper suggests the use of a hot-spot detection tool for PV modules, based on condition monitoring by infrared thermography. The experimentation of the intended approach includes several daily sets of in-situ thermography measurements of specific PV arrays, installed on the rooftop of a laboratory building in the School of Engineering Campus of Democritus University of Thrace (DUTH), Greece. Further processing of the obtained thermal images, by means of a basic image histogram and line profile analysis, provides useful data for the detection and quantification of hot spots within each PV module. In particular, specific variations in the morphological features of both thermal images’ histograms and linear profiles witness the presence of defects, their source within the module and, ultimately, their impact on the degradation of the inspected PV array’s performance due to the hot-spot heating effect.