Large-Scale Distribution Systems: Solar Integration and Load Demand Fluctuation Case Studies

The modern-day power grid is continuously growing as the integration of renewable energy, such as wind and solar, increases. These distributed energy resources (DERs) cause two-way power flows, where power also flows upstream toward the feeders in distribution networks. High penetration of these resources can cause issues in the grid, such as, but not limited to, voltage fluctuations, switching frequency effects at the devices on the grid-edge, and line overloading, which are essential to study and analyze to ensure system stability and resiliency. Hence, the work in this paper performs two case studies on large-scale distribution networks, focusing on different levels of solar integration and load demand fluctuations. Efforts such as these are crucial to existing power system planning and capacity studies, in which our analysis and results provide a deeper understanding of solar integration effects on large-scale networks. Our analysis, for example, can demonstrate how utilities can consider PV system integration as an option to ease line overloading instead of costly transmission line upgrades. These improved models and control studies also improve the potential for comprehensive cyber-physical contingency analysis studies for better resilient large-scale distribution networks.