Impact of an Electric Truck Charging Station on the Small-Signal Stability of MV Grid

Abstract

This paper investigates the impact of an ETCS on the small-signal stability of the medium-voltage (MV) grid to which it is connected. An analytical approach based on a state-space model of the grid that integrates the ETCS is developed to analyze the movement of eigenvalues in the complex plane. In addition, time-domain simulations are conducted to investigate rapid voltage changes and the dynamic response of the power exchanged between the AC grid and the ETCS. The considered DC microgrid is represented by an equivalent model, where the overall system dynamics are dictated by the DC bus. A Belgian local MV network is used as a case study, with dynamic modeling performed in DIgSILENT PowerFactory. The obtained results show that the equivalent truck charger introduces an additional stable mode, whose movement is dictated by the connection rate of the subscribed load power at the load buses. Furthermore, the rapid voltage change resulting from the sequential connection of trucks rated is estimated to be 3.5%