Power generation by unhealthy photovoltaic modules

Hotspots are one of many defects that can occur on degraded photovoltaic system, yielding a detrimental effect on the PV module production. Infrared thermography was used to detect and quantify the severity of hotspots. Temperature difference between overheated and healthy areas was assessed. Four PV modules were analysed, one of them presenting a hotspot.
A model for both healthy and unhealthy PV modules was developed, based on the single diode solar cell model and considering, exclusively, data-sheet parameters. To validate the model, the outputs for these working conditions were compared with the real outputs of the studied PV modules, which were previously measured and stored.
The relationship between the severity of a hotspot and its respective impact on the power generation of the PV module was studied and the consequent monetary loss can be assessed. Thermographic analysis was enhanced as an optimizing decision-aid tool for the operation of photovoltaic installations.