Influence of Fast-Moving Cumulus Cloud on Power Quality of Emerging Grid-Tied Solar Farms with Heterogeneous Control Techniques: A Case Study

The international renewable energy agency (IRENA) estimates that, in the upcoming future, 90% of the world’s electricity will be from renewable energy sources. Among available sources, solar is gaining popularity because of its easy maintenance and availability. The unavoidable variability of solar irradiation can cause detrimental impacts on power grids. One of the main reasons for rapid irradiance transitions is fast-moving cumulus clouds. Impact of such clouds on power injected into the grid by solar farms and hence on the power quality is not well studied in literature. Temperature of solar panels, heterogeneous control methods followed by grid-tied inverters, and the strength of the bus bar at the point of common coupling (PCC) are the principal factors that decide the impact. This paper illustrates such an impact through simulation-based case studies conducted on an IEEE-9 bus system. Reactive power injection to the grid by the solar farms are considered, and case studies are conducted for various penetration levels of grid-following and grid-forming inverters. The results for the case studies can significantly contribute to the design and selection of flexible dispatch systems like energy storage.