Performance Analysis of Hybrid Power Plant under Varying Grid Conditions

Large synchronous generators are being retired, while inverter-based renewable energy sources (IBR) are increasing, weakening future power system strength. As the grid weakens, grid-following (GFL) IBRs may become unstable. However, grid-forming (GFM) IBRs can reinforce weak grids, ensuring stability. Hybrid power plants (HPPs) with GFM and GFL can operate in very weak grids. However, the dynamic differences of IBR plants complicate interactions between plant-level controllers in HPPs. This study uses advanced modelling and time-domain simulations to examine HPP dynamic behaviour under various grid strengths. An HPP with three IBR power plants is used to evaluate the centralised, hierarchical control system under different system strengths and X/R ratios. The HPP’s stability boundary is maintained across different system strengths. The findings improve our understanding of the interactions between the HPP and the grid and support optimised design and operation strategies for future energy systems.