Spectral influences on estimations of useful irradiance for different PV technologies

Reference solar irradiance is the most influential parameters for accuracy of PV systems monitoring. Due to new cells technologies a magnitude of spectral effects is widely discussed nowadays. No comprehensive measurements are taken to resolve this debate. This paper discuss utilization of the spectral measurements in a PV system monitoring. Analysed data come from dedicated monitoring systems and include broadband and spectral irradiance, module short circuit current, module temperature, ambient temperature humidity and wind-speed. It has been shown what are the variations in the solar spectrum over the different types of overcast and how does the different module technologies react on those changes. Investigating distribution of the solar spectral irradiance is a complex task. Conclusions discuss usability of the spectroradiometers as the reference sensors and problems that still stays unsolved in the field of spectroradiometry.