Power quality measurements reveal vehicle-to-grid (V2G) influence from charging and discharging

As electric vehicle (EV) adoption grows, technologies like smart charging and Vehicle-to-Grid (V2G) become essential for managing peak loads and enhancing grid stability. However, these technologies also raise concerns related to power quality. This paper investigates the impact of bidirectional charging on power quality, using experimental data from an EV connected to a single-phase bidirectional charger with nominal power of 7.4 kW. Voltage changes and unbalances, as well as harmonic disturbances and total harmonic distortion (THDi), are measured for different power levels and compared with regulatory limits. The results show that the voltage of the loaded phase drops during charging and increases during discharging . Voltage unbalances are more pronounced during charging than discharging across all power levels, suggesting that V2G technology could help stabilize the grid. Harmonic disturbances are observed during both charging and discharging, with minimal differences between the two modes. These disturbances are most pronounced at power levels well below nominal power. All voltage and harmonic disturbances remain within the regulatory limits for the low-voltage distribution grid for the single EV in this study. However, simultaneous charging of several EVs could become pose challenges for power quality. These findings underscore the need for advanced control strategies and power conditioning systems to mitigate adverse impacts on power quality during bidirectional charging. Developing filters in V2G chargers to filter out harmonic interference is a potential solution.