Reactive power support in residential LV distribution grids through electric vehicle charging

This article discusses the impact of reactive power support of single-phase electric vehicle chargers, during charging, in a low-voltage residential distribution grid. For a representative Flemish case study, reactive power support is investigated for three different electric vehicle charging strategies: uncoordinated charging, residential off-peak tariff charging, and vehicle-based peak shaving. For an increasing electric vehicle penetration rate and an increasing amount of reactive power injection, the impact on the residential voltage deviations, peak load, and grid losses is calculated. The results of the case study show that the implementation of a capacitive load behavior in electric vehicle chargers has a beneficial impact on the voltage deviations. Furthermore, for a capacitive power factor of 0.95 or higher, there is no disadvantage with respect to the residential peak load and the residential grid losses. However, the cost related to the increased apparent power rating of the vehicle chargers, required to supply the reactive power, should be assessed compared to the mentioned advantages. If the benefits outweigh the costs, reactive power support could be considered in the grid compliance requirements of electric vehicle chargers, as it allows deferring distribution grid infrastructure investments.