Wind turbine generator modeling considerations for stability studies of weak systems

High levels of renewable energy sources (RES) can significantly impact system stability and system resilience as conventional generators are replaced by these units. Typically, positive sequence models of RES are used for stability analysis and interconnection studies of RES. Although these models can accurately represent the dynamic behavior of RES, there are certain limitations of their usage. This paper focuses on the limitations of positive sequence RES models when used for stability studies of weak grids. The limitations arise due to simplified controller representation and neglect of controllers' fast dynamics, in comparison with EMT models. The paper demonstrates those limitations by comparing the simulated response of RES in positive sequence and EMT platforms for a weak system.