Long term reliability evaluation of PV module

Long-term reliability of photovoltaic (PV) module is important for the reliability of the photovoltaic generating system. Especially, the milky white phenomena and the series resistance increasing of crystalline silicon PV module influence the output of PV module. To establish the method of causing these phenomena accelerating on PV module, the research is executed. This paper describes the outline of testing method of long-term reliability for PV module, and the initial results are explained. Furthermore as the evaluation technology of degradation level, the measurement method of characteristics of each cell in module is explained.