Optimal Use of Existing Distribution Feeders to Accommodate Transportation Electrification

An analytical method that can be used to study the optimal topology and maximum capacity of the existing distribution network to accommodate electric vehicle (EV) charging demands is presented in this paper. In order to facilitate a large number of EV integrations, the feeder reconfiguration problem is formulated as a discrete nonlinear optimization problem that finds optimal feeders´ tie switch locations and their on/off schedule to minimize operation costs and comply with the system operation constraints. A novel stochastic dynamic programming technique is adopted to solve the problem that includes various uncertainties associated with feeder baseline and EV charging loads. Simulation results obtained from an 84-bus feeder test system have indicated that for a case with 20% EV penetration to a 70% capacity utilization feeder area, a 10.78% reduction of operation cost and a 14.4% decrease in maximum feeder utilization can be obtained by distribution feeder reconfiguration.