Laboratory Intercomparison on a Shading Resistance Classification of PV Modules

Shading of PV modules can significantly reduce the performance of PV installations, particularly in rooftop installations. We have developed a classification scheme based on a shading metric to rate PV modules according to their shading tolerance. The results of a laboratory intercomparison, where four participating labs applied the metric to four PV modules with different shading mitigation strategies, are presented. Indoor and outdoor measurements were conducted using a strict procedure developed for reproducibility and future standardization of the scheme. A lab also provided simulations of the PV modules for comparison with the measured results. Consistent ratings were obtained by all participating labs for all examined PV modules under two of the three proposed shading conditions.