Different techniques can be used to detect and quantify PV modules anomalies, as visual inspections,
electrical tests like the I-V curve test, infrared thermography (IRT) or electroluminescence (EL). PV plants operators
usually apply only one or two of them within the Operation and Maintenance (O&M) activities. Additionally,
researchers usually studied them separately. However, these methods provide complementary results, glimpsing
interesting information about the PV site state. The main strength of the research performed is the simultaneous study
of all these inspection techniques, studying the correlation between them. Results confirm that, EL and IRT under
current injection on modules are closely correlated, while IRT under normal operation (sun exposure) reveals
complementary information not detected in EL but existing in the visible spectrum. In conclusion, it is advisable using
as many techniques as possible to characterize the actual state of the module and to explain its I-V curve.
