Assessing Power Quality Disturbances Caused by Urban EV Fast Charging Stations in Low Voltage Grids: A Case from Kavacik, Istanbul

The establishment of a large number of Electric Vehicle Charging Stations (EVCSs) increases the attractiveness of Electric Vehicle (EV) use. However, these types of charging stations are classified as mobile and non-linear loads in electrical power systems. This situation introduces new challenges of a scale and nature that electricity distribution networks are not accustomed to. Considering technological changes from the past to the present, it is predicted that Electric Vehicle Fast Charging Stations (EVFCS) will constitute a significant share of all types of EVCSs. Consequently, many electrical issues are likely to emerge in the grid with the integration of these charging stations into the distribution network. Considering the concerns about these potential problems and strategies for mitigating them, it is crucial to examine the possible electrical impacts of EVCSs on the distribution network. In this study, substations, transformer substations, transformer points, HV/LV distribution feeders, and loads belonging to the distribution company were analyzed in the pilot region of Istanbul/Kavacik. The locations of existing stations in the region were taken into account when determining the placement of EVCSs on the distribution network. The simulation of the system is modeled using MATLAB/Simulink software, incorporating real-time technical data such as the location of distribution transformers, power data, load density, and the number and length of feeders, along with data on system protection and control elements. When the simulation results are analyzed, it is noted that the current value drawn in the feeder to which the single-phase EVFCS is connected increases by approximately 32%, while this value rises by 75% in all phases of three-phase EVFCS systems. Although the total harmonic distortion value did not increase significantly in single-phase systems, it was found to exceed the limit values in three-phase systems. It was confirmed that the voltage drops did not surpass the permitted limits.