Efficient Determination of Distribution Tariffs for the Prevention of Congestion from EV Charging

A dual objective electric vehicle (EV) charging schedule optimisation is proposed here whereby both consumer driving requirements and grid constraints are respected. A day-ahead dynamic tariff (DT) for distribution systems is proposed as a price signal to EV fleet operators (FO) bidding into the day-ahead market. The DT acts to disperse charging at congested periods and locations, thereby preventing congestion on a day-ahead basis. The magnitude of the DT is determined from a simulated locational marginal prices (LMPs), and the time extent of the DT is determined from analysis of the system loading curve prior to the application of the DT. Case studies were performed using a sample distribution network modelled on a network from the Danish island of Bornholm. A variety of price profiles were used to illustrate the efficacy of this approach. The case study results show that this approach is highly efficient at grid congestion prevention, and the precise level of congestion that can be alleviated is dependent on the price profile of the optimisation period in question.