Reducing uncertainty in outdoors PV module characterisation

Abstract

Quality control of PV modules in large grid-connected PV plants is typically accomplished by means of indoors testing at qualified laboratories which use solar-simulators. Nevertheless, outdoors on-site measurement of PV modules has several advantages: the devices required to measure the PV modules are much cheaper than solar simulators; the costs and effort related to disassemble and to transport the PV modules to the laboratories are entirely avoided; and the safety of the modules against undesirable cracks and/or module breakage during their manipulation is drastically improved (manipulation is just reduced to unplug and to plug the connectors). Besides, the uncertainties related to outdoors PV module measurements are also strongly reduced when reference devices to measure effective incident irradiance and solar cell temperature are properly selected. These uncertainties are even lower when considering the different response of each PV module to the same real weather conditions is taken into account, especially those related to cell temperature. So uncertainties of outdoors measurements can be reduced close to those ones obtained with the indoors characterisation. This works deals with the temperature dispersion inside PV modules and between different PV modules, as well as how to manage this dispersion when the PV modules are characterised outdoors to obtain accurate results with a reduced uncertainty.