A stochastic distribution operations framework to study the impact of PEV charging loads

In this paper, an extensive study on plug-in electric vehicle (PEV) driving characteristics, charging behavior and their impact on the utility is presented. The primary challenge in investigating the effects of PEV charging loads on the distribution system is taking care of the uncertainties. A detailed study on National Household Travel Survey (NHTS) data is carried out and the PEV charging behavior is modeled. Thereafter, a stochastic optimization model is proposed considering different PEV charging scenarios with their associated probabilities and the impact on system load, feeder loss and voltage deviation are studied. A Distribution Optimal Power Flow (DOPF) model with various objectives such as feeder loss minimization, energy drawn minimization and PEV charging cost minimization subject to feeder operational constraints including PEV charging within a 33-bus balanced distribution system is presented. In the uncontrolled charging case, the worst case scenarios are discussed. The proposed smart charging model provides with the optimal charging schedules which result in flattening the load profile.