Increasing penetrations of distributed solar photovoltaics (PV) require more detailed modeling of distribution grids to determine the amount of PV that can be safely accommodated and to understand potential operating impacts. This detailed modeling requires high frequency and high spatial resolution inputs of PV production and load. This talk will discuss the availability of these granular inputs, errors when using only coarse inputs, and a method for generating synthetic but representative inputs to enable accurate simulations with limited input data. Specific examples for Puerto Rico based on solar measurements from Mayaguez and Carolina will be presented.