Prolonged degradation and reliability assessment of installed modules operational for 10 years in 5 MW PV plant in hot semi-arid climate

Abstract

The current work presents detailed degradation and reliability assessment of installed PV modules in grid tied 5 MW solar PV plant in hot semi-arid climate. Defects and failures of 336 modules out of 2078 visually inspected c-Si modules with 10 years of operational period in hot semi-arid climate is evaluated using FMECA statistical tool and I-V curve measurement. The novelty of the research conducted is presenting long term degradation of PV modules in utility scale PV plant installed for 10 years in outdoor environment in remote location, carrying FMECA analysis of visually degraded modules along with on-field electrical characterization. Correlation of identified defect and failures with electrical parameters of PV module is also presented. The results obtained indicate light and dark EVA discoloration, EVA discoloration with cell and metallization discoloration, snail trails, backsheet burnt, glass breakage with or without cell cracks to be the most dominant and frequently occurring defects and failures with high severity. The inspected plant has considerable degradation as compared to other plants in the same area in hot semi-arid climate and therefore degradation investigation of the plant is important in identifying various possible causes of observed degradation and studying impact of degradation on module performance. Based on the results obtained and analysis conducted, several important preventive and corrective measures along with important recommendations have been enlisted for mitigating failures and improving the system performance.