Impact of Electrical Vehicle Private Charging Stations on the Quality of the Low Voltage Network Supply

The appearance of new single-phase intensive and often coincident loads, such as the electric vehicle private charging stations (i.e., residential or private parking lots of shopping malls or workplaces), can affect the operation of low voltage (LV) distribution networks. Unbalances among the three-phase loading are extremely common, even if the end-users of a given LV network have similar behaviors. Due to the coincidence of such loads, excessive voltage drops may often appear, altering the quality of supply voltage provided to the LV end-users. This work evaluates the effects of residential and other charging stations located in parking lots of shopping malls or workplaces on the quality of supply voltage of LV grids. Then, a decentralized approach is proposed, based on the multi-agent system, which allows the different flexibility resources available on the grid to act together to improve the network quality. The agents cooperate to regulate the network nodal voltage, taking into account the characteristics of the resources they are controlling and the needs of their owners. A case study derived from a real portion of the Italian distribution system demonstrates the validity of the approach in solving the network operation criticalities.