Potential of EV Charging Stations for MV Grid Voltage Support

Abstract:
The additional power demand in the electric grid resulting from fast charging influences the hosting capacity of highly loaded distribution grids, which impacts the number of charging stations that can be installed. The active power demand of charging stations depends on the charging profile, the parking time and the rate of usage. As a result, the daily demand is often lower than the installed capacity, which leads to the potential of grid voltage support by reactive power injection in the medium voltage grid. If the available reactive power is insufficient, charging power can be curtailed, giving priority to voltage support. In this work, the potential of charging stations to provide such service in a benchmark grid of an urban distribution grid based on real charging profiles is analyzed for fast charging stations connected to the medium voltage grid. The trade-off between power rating to account for grid voltage support and power rating without participation at reactive power market is shown in an economical analysis based on fixed remuneration for reactive power provision.