Impact Analysis of EVs and DERs on the Bulk Grid Through T&D Co-Simulation

The increasing penetration of distributed energy resources (DERs) and electric vehicles (EVs) in distribution grids necessitates studying the transmission and distribution (T &D) system in an integrated manner. This paper proposes a T &D co-simulation approach using Positive System Load Flow (PSLF) and Open Distribution System Simulator (OpenDSS) to examine the impact of DER and EV penetration on the large scale T&D grids. A mathematical model for EVs is proposed for the tightly coupled co-simulation framework. The proposed EV model and DERs with volt-var control are incorporated into practical distribution feeders, each with 5,647 nodes, and co-simulated after connecting them to the IEEE-118 transmission system. The simulation results demonstrate the functionality of the EV model and the impact of DERs and EVs on substation voltages. Additionally, the impact of DERs and EVs on the ramp rate of net load at the distribution substation bus and the generators in the transmission network is also analyzed.