Mitigating Impacts of Plug-In Electric Vehicles on Local Distribution Feeders Using Charging Management System

Number of Plug-In Electric Vehicles (PEV) has increased significantly during the recent years, causing severe impacts on operation of power distribution systems. This study develops a new Charging Management System (CMS) to regulate PEV charging activities to minimize the PEV unwanted impacts. Its algorithm employs a 3-tier charging control mechanism that prioritizes low-battery vehicles and rolling switching of charging stations. The CMS is evaluated using a 14.4-kV distribution grid and PEV public charging station data of the Los Angeles Department of Water and Power (LADWP). Results show that the CMS can regulate the PEV charging to raise the grid voltages effectively. Under a grid heavy loading condition where its feeder voltages drop to 0.93pu, the CMS can bring all critical voltages back to normal of 0.95pu after two control cycles. In addition, the CMS improves the grid load supply capability by up to 8.5%. It ensures better charging level for PEV. The battery state charge under the CMS is 76% for 8-hour control, improved by 14.5%, as compared with a two-tier charging