Avaliação do desempenho de módulos fotovoltaicos com mais de 10 anos de exposição em campo

Abstract

This paper presents the results of the investigation of performance losses ofphotovoltaic moduleand the identification of component failure and durability issues. Therefore, this study used thesample collection obtained of the approximately 1000 stand-alone PV systems, which include solar home systems (sized 150 Wp) and schools systems (approximately 2000 Wp). These were commissioned and are operated by the Energetic Company of Minas Gerais (CEMIG). These PV systems are installed in the state of Minas Gerais, with the oldest 10 years in operation. The stand-alone systems are located at northern and eastern region of Minas Gerais. These areas are considered subtropical climate zones, with dry winters and rainy summers. These systems had not had a rigorous evaluation for their reliability and operation performance—with no reporting of any module ageing or identifying major degradation mechanisms. Following accepted power-plant evaluation methodologies, we used visual inspection procedures to identify the major PV module degradation modes as gradual encapsulant discoloration and delamination—that may be caused by the high incidence of ultraviolet radiationexisting, as well as presence of deposited dirt on the modules, with until 20% obscuration transmission. This paper provides an initial analysis of the visual inspection results of photovoltaic modules, the identification of the degradation modes, and the steps taken to restore acceptable levels of operation (e.g., regular inspections and periodic cleaning schedules).At the next step further degradation will be investigated in a larger sample of modules, with performance electrical test and statistical analysis of the failures of the PV systems installed in Minas Gerais.