Hybrid power plant control in weak grids: grid following vs. grid forming

This paper studies the performance of grid-following and grid-forming controllers utilized as asset level control in Hybrid Power Plants (HPPs) while connecting to weak grid. In this regard, the overall configuration of HPP consisting of wind, solar and battery energy storage system has been simulated in time domain, using PSCAD software. In addition to that, hierarchical controller has been utilized to provide three layers of control in this configuration. Since synchronization can be considered as one of the main control challenges while operating in weak grids, grid-forming controllers are studied to show the superior performance and maintaining stability of hybrid power plants in such cases. Then, varying the weaknesses of the grid in terms of short circuit ratio, stable operation of the HPP has been studied using the abovementioned controllers. The results of this study can be utilized in control and operation planning of HPPs considering the growing challenges of weak grids.