Dynamic Stability Assessment for Integrated Transmission-Distribution System Considering Distributed Energy Resources

The importance of considering integrated transmission and distribution (T-D) system planning and operation has been increasingly recognized. Most research focuses on steady-state analysis, yet the dynamic behaviors of T-D systems have not been thoroughly studied, especially with deeper penetration of distributed energy resources (DERs) largely altering system dynamic characteristics. In this paper, we attempt to investigate the impacts of aggregate DERs on transmission side dynamic stability. Time domain simulations are performed for dynamic stability assessment. Simulation results demonstrate how the grid-connected DERs affect overall system dynamics under different scenarios. Furthermore, smart inverters with grid-support functions have also been examined via simulations to mitigate the adverse impacts on stability caused by DERs.