Performance Evaluation and Enhancement of an Electric Vehicle DC Fast Charging Station in a Weak Distribution Feeder

This work investigates and evaluates the performance and impact of a dc fast charging station (DCFCS) in a rural distribution feeder under various grid conditions. The station includes three de fast chargers, each of which is rated at 360 kW and %0 V. The studies are conducted in time-domain using the off-line PLECS software platform. The studies show that the point of common coupling (PCC) voltage drop limits the lowest short-circuit ratio (SCR) that the DCFCS can satisfactorily operate with. An enhancement method, utilizing both a load curtailment strategy and a battery energy storage system, is consequently proposed to maintain the PCC voltage above its lower limit under low SCR conditions, thereby extending the charging station's range of operation. RTDS-based real-time simulation results i) verify that the enhanced DCFCS is able to operate under the extended grid condition and ii) demonstrate the hardware implementation feasibility of the proposed methodology.