An electric vehicle charging station operation model with hourly capacity mechanism

With the increasing penetration of electric vehicles (EVs), the EV charging load (EVCL), characterized by high power demand and uncertainty, consumes grid capacity and increases the operational cost of the distribution network (DN), posing challenges for EV charging stations (EVCSs) and limiting the integration of other loads. This paper proposes an hourly capacity mechanism to guide EVCS operation in the DN. Compared to traditional models, the proposed approach innovatively incorporates an hourly capacity payment and establishes a bi-level model based on hourly capacity and time-varying prices. A tailored algorithmic solution is developed to efficiently solve the bi-level optimization problem. Case studies on a modified IEEE 33-bus system show that the proposed model reduces EVCS hourly capacity by an average of 24.33 %, and lowers operational costs for the EVCS and DN by 11.38 % and 1.15 %, respectively, while ensuring secure grid operation and preventing voltage deviation. Sensitivity and scalability analyses confirm the model's robustness under increasing EV arrival rates. The computational burden is also evaluated, demonstrating the approach's practicality and engineering value.