Cross-correlation Analysis of the Indoor Accelerated and Real World Exposed Photovoltaic Systems Across Multiple Climate Zones

The authors demonstrate a method to calculate the cross-correlation scale factor (CCSF) which rescales the time between indoor and outdoor degradation models. The CCSF is further applied to obtain the cross correlation coefficients(CCC) between the models of outdoor modules located in three climate zones and the indoor accelerated tests using damp-heat and thermal cycle exposures for five commercial PV module brands. We evaluate and compare the performances of different combinations based on the CCC, to determine the indoor accelerated test which is most closely related to real world conditions at each site. The result shows that the cross correlation coefficients among some combinations between the outdoor model and indoor model are over 0.9, and we further compare the trend of I-V features between indoor and outdoor modules to evaluate the degree of similarity of degradation mechanisms between indoor and outdoor modules. The result obtained from these two comparison methods are in good agreement with each other.