Three-level hierarchical microgrid control-model development and laboratory implementation

This paper presents a three-level hierarchical control approach for microgrids in grid-connected mode. The first level optimizes microgrid operation in the long run, e.g. 15 min, with the goal of minimizing microgrid's operating costs. The second level takes part in frequency control in grid-connected microgrids. It utilizes a Model Predictive Controller and Kalman Filter based on available frequency measurements in the microgrid. The third level is the plant level, in which classical controllers are used for tracking optimal set points received from upper two control levels. The developed control scheme is applied to the Smart Grid Lab (SGLab) at the University of Zagreb Faculty of Electrical Engineering and Computing. The findings from this close-to-real-world application are also presented.