Distribution Feeder Impacts of Electric Vehicles Charging in an Integrated Traffic and Power Network

Electric vehicles are considered to be flexible loads due to their elasticity in both charging time and location. Because a larger number of electric vehicles are expected to be connected to the grid for charging, the total load of the distribution network will increase and may negatively impact the grid. This paper designs a method to determine electric vehicle charging demand at various nodes in a distribution system. The fluctuation in the charging load with time is due to random movement of electric vehicles in an integrated traffic and power network. Uncoordinated and semi-coordinated charging scenarios are simulated. Monte Carlo simulation is performed to analyze the effect of uncertainty in driving behavior in a medium voltage distribution network. Results show that uncoordinated charging techniques generate new peaks in the load profile of each node in the distribution system and cause power network congestion problems. Semi-coordinated charging techniques introduce a delay in the charging time to shift EV charging loads to off-peak times. Hence, with this technique, it is unnecessary to immediately upgrade distribution network infrastructures to avoid network overloading.