An MILP Method for Optimal Planning of Electric Vehicle Charging Stations in Coordinated Urban Power and Transportation Networks

The growing urban mobility and the proliferation of electric vehicles (EVs) have called for expansions of electric vehicle charging stations (EVCSs) as well as large upgrades to power distribution networks (PDNs) and transportation networks (TNs). This paper proposes an MILP method for the coordinated planning of coupled PDN-TN (CPTN), which determines the optimal deployment of new roads in TN, optimal placement of EVCSs along those roads, and optimal expansion of PDNs to accommodate EVCSs. First, we analyze drivers' charging and routing behaviors, then develop and solve a bi-level discrete TN model with EVs. Next, we formulate a bi-level CPTN model which includes CPTN investment and PDN operation decisions at the upper level and traffic flow assignment at the lower level. Third, we improve the traffic assignment model to better capture its interplay with EVCS and road investments. Moreover, to tackle the computational complexity of the proposed bi-level model and potential infeasibility under existing method, we propose an improved Big-M method to acquire a tractable MILP solution. Finally, we present numerical studies for a modified real-world urban TN, which verify the effectiveness of the proposed CPTN method. In the proposed case studies, the necessity and potential benefits of the coordination between TN and PDN and the consideration of user's rationality are investigated.