Reduction of Uncertainty of Outdoor PV Module Characterization: Test Field Experiences

This research provides insights from outdoor monitoring and characterization of PV modules. We compare results from two test sites: a previously used rooftop installation and the newly established test field of Fraunhofer ISE in Merdingen, Germany. The primary focus is on analyzing uncertainties in outdoor current-voltage (IV) curve measurements caused by effective irradiance and module temperature. The study addresses factors affecting irradiance measurements, including device calibration, low irradiance levels, high angles of incidence, and site mounting configurations that caused partial shading. Additionally, it examines uncertainties related to module temperature, such as measurements non-uniformity at array level and differences from cell to PV module’s backsheet. We bring practical insights from Fraunhofer ISE's test field experiences and by assessing the impact of installation conditions on PV module measurement accuracy, we hope to contribute on the reduction of these uncertainties. The findings are intended to guide researchers in optimizing monitoring setups and highlight the importance of accurate irradiance and module temperature measurements.