Correlation of electrical and visual degradation seen in field survey in India

This paper presents an analysis of the electrical and visual degradation data gathered in the 2^nd All India Survey of Photovoltaic Module Reliability, conducted in 2014, in which a total of 1148 modules were inspected in different climatic zones of India. The modules in the Hot Climates are seen to degrade faster than modules in the Non-Hot climates. Fill Factor (FF) reduction has been found to be the main cause for power reduction in young modules (less than 5 years old), while for old modules (more than 5 years), I_sc reduction is the main culprit. Visual degradation in the modules has been quantified and correlated with the degradation in various electrical parameters. The degradation in I_sc correlates with the discoloration and delamination of the encapsulant and the degradation in the FF correlates well with the extent of the corrosion in the metallization.