A cloud shadow model for analysis of solar photovoltaic power variability in high-penetration PV distribution networks

The primary challenge with high penetrations of solar power into power distribution feeders lies in the solar resource's inherent variability and uncertainty during partly cloudy days. To avoid unnecessary limitations to the rapid integration of PV to the grid, there is a need to understand and characterize PV variability from the prospective of utility operators and planners. To this end, this paper presents an easily implemented cloud shadow model to simulate realistic solar power variability of both distributed and large centralized PVs at various locations on a feeder at one second intervals. Power of four actual PV plants installed on an EPRI test feeder is simulated using the cloud shadow model and compared to actual one second measured data. The practical usefulness of the proposed model is confirmed by examining the distribution of PV ramp rates at time windows ranging from 10 to 60 seconds as well as the correlation between modeled and measured power output.