Grid Integration of High-Power and MW-Class Electric Vehicle Charging: Impacts, Severity Factors, and Mitigation Strategies

The increasing power levels of electric vehicle (EV) charging infrastructure, from conventional direct current (DC) fast charging to extreme-fast charging (XFC), ultra-fast charging (UFC), and emerging megawatt-class systems, are creating increasingly concentrated electrical demand at the grid interface. This paper reviews the grid interaction of high-power DC charging infrastructure by linking charging-power progression with the resulting grid impacts, the factors governing their severity, and corresponding mitigation strategies. The principal impacts include peak demand, voltage deviations and fluctuations, harmonic distortion, voltage and current unbalance, transformer and feeder loading, network losses, reactive-power requirements, and system-level stability and reliability. The synthesis shows that rated charging power alone does not characterize grid exposure; actual impacts also depend on charger utilization and simultaneity, vehicle charging characteristics, grid strength and available network capacity, and spatiotemporal charging patterns. Mitigation strategies include power electronic converter (PEC) control, battery energy storage system (BESS) and renewable energy source (RES) integration, DC microgrids, coordinated charging, vehicle-to-grid/vehicle-to-everything (V2G/V2X) operation, and grid-aware planning and reinforcement. Key research needs include realistic charging-demand representation, assessment across different grid-strength conditions, field validation of XFC/UFC and MW-class installations, multi-timescale analysis, and coordinated evaluation of mitigation strategies.