Qualitative Multimodal Diagnostic Assessment of PV Installations: Field Results from the PROMISE Second Advanced School in Malta

This paper presents the technical outcomes of a multimodal diagnostic assessment conducted during the PROMISE Advanced School in Malta. Attendees of the school utilized a suite of complementary measurement techniques, ranging from visual inspection to electrical characterization and advanced imaging techniques such as drone infrared (IR), magnetic field imaging (MFI), electroluminescence (EL) and ultraviolet fluorescence (UVF). These were applied to four residential photovoltaic (PV) installations. By leveraging the strengths of each method, the study demonstrates how multimodal assessments enable a more accurate and comprehensive understanding of module degradation, electrical anomalies and material failures. Faults such as microcracks, inactive cell areas, broken interconnects and semiconductor breakdown were identified and cross-validated across different techniques. For instance, MFI confirmed current path disruptions identified using current-voltage (I–V) tracing, while EL-detected semiconductor breakdowns were linked to IR-confirmed hotspots. This approach improves diagnostic accuracy and reduces ambiguity in fault attribution. To the authors’ knowledge, this is among the first field-based studies combining these complementary techniques on operational residential PV systems. The findings contribute actionable insights for reliability analysis, predictive maintenance, decommissioning and quality assurance in PV systems.