Weather forecast-based power predictions and experimental results from photovoltaic systems

Considering the distributed generation from solar energy, the topics of this paper are multiple: firstly, to analyze accurate measurements of solar irradiance from pyranometer and to compare them with 1-3 day weather forecasts by the suitable statistical error parameters. Then, to describe a detailed PhotoVoltaic (PV) conversion model, from the solar irradiance to the AC power profile delivered to the utility grid, and to compare the simulation results with the 15-min mean power measured by the energy-meter of a real grid-connected PV system with megawatt size. The results show that an adequate accuracy can be obtained and that useful information can be provided for fault diagnosis of a portion of a PV array.