Detecting defects in photovoltaic cells and panels with the help of time-resolved thermography under outdoor environmental conditions

This paper investigates defects in photovoltaic (PV) cell and panels, in particular, the size and location of defects. We concentrate on characterising photovoltaics under outdoor environmental conditions with the help of synchronized thermography (ST) and time-resolved thermography (TRT). Infrared (IR) images are obtained under changing solar radiation levels and moderate wind speeds with the help of a table IR-camera. We demonstrate that IR-images obtained outdoors by ST and TRT provide the same information in the same accuracy as IR-images recorded indoors. We elaborate the differences in parameters such as measurement time and region-of-interest (ROI) which need to be adjusted when moving from indoor to outdoor environments. Our technique allows maintenance staff to carry out measurements on the site of a PV power plant to identify PV panels with defects in an easy way.