A simple diagnostic method for generating power lowering by utilizing the rated value of a photovoltaic module

摘要

On a photovoltaic (PV) power system, diagnosis of generating power lowering is necessary. But, the diagnostic method of generating power lowering has not been established, yet. The authors are studying a diagnostic method of a PV generating system. In this paper, we described the relationship between rated value and generating power of a PV module on the influence of the environmental factors such as climate, season and so on, and proposed a simple diagnostic method for generating power lowering by utilizing the rated value of a PV module. The experimented values of generating power of a PV module increased linearly with the increase of the irradiance without regard to the environmental factors. It was clear that the experimented values of generating power are higher than 75% Line (connected the origin of coordinates to 75% of the rated value of a PV module). From these results, it was suggested that the threshold line of diagnostic method for generating power lowering is 75% Line. The authors proposed a simple diagnostic method using the 75% Line.