Photovoltaic Power Generation: Modeling Solar Plants´ Load Levels and Their Effects on the Distribution System

Both the renewable portfolio standard requirements and the potential to delay distribution upgrade expenditures has resulted in a vast increase of distributed energy resources (DERs) on utility systems. As a result, distribution engineers are confronted with the very challenging task of fulfilling the scope of a system impact study to determine whether there exists the potential for the DER to create any adverse operational or voltage issues, now or in the future, as system changes occur. Fortunately, there are industry standards and guides that describe how to fulfill the technical study requirements with some step-by-step guidance. The complexity of the system impact study also depends heavily upon the type and size of the DER and its operating modes. An all-encompassing study might cover a vast number of areas with just a few of these being voltage and stability analysis, harmonics, transients, distribution system protection, and DER relaying requirements. Predicting photovoltaic (PV) generation profiles for different seasons and hours of the day rests heavily on the plant design and layout.