  The growing proliferation in solar deployment, especially at distribution
level, has made the case for power system operators to develop more accurate
solar forecasting models. This paper proposes a solar photovoltaic (PV)
generation forecasting model based on multi-level solar measurements and
utilizing a nonlinear autoregressive with exogenous input (NARX) model to
improve the training and achieve better forecasts. The proposed model consists
of four stages of data preparation, establishment of fitting model, model
training, and forecasting. The model is tested under different weather
conditions. Numerical simulations exhibit the acceptable performance of the
model when compared to forecasting results obtained from two-level and
single-level studies.
