Impact Of Large-scale Electric Vehicles On Power Grid And Charging Infrastructure Planning

The transport sector is undergoing worldwide tremendous changes due to pressurecaused by energy crisis and global warming. Electric transportation has many attractivefeatures including decreasing greenhouse gas emissions and reducing dependence onimported petroleum to keep energy security. During the next years, it is expected thatthere will be a considerable increase in the number of Electric Vehicles (EVs). In order toimprove the penetration of EVs, a large number of countries are interested in constructingcharging infrastructure to make electric cars more easily access the power system.However, charging demand for EVs will bring new load on power system, the disorder ofcharging will adversely affect the safety of system operation. Therefore, it’s veryimportant to quantify the effect of adding large scaled EVs onto the power grid. Andresearches on charging facilities optimize planning can increase the acceptance of EVs topower system which supporting the healthy development of EVs.In researches on spatial and temporal distribution of electric vehicle chargingdemand, data on private cars is used to analyze driving behaviors to give temporaldistribution of EV charging demand. At the same time, GPS information of some taxiesare used to build spatial distribution of EV charging demand based on the relationshipbetween taxi GPS information and charging load geographical distribution. Then,forecasting methods for the proportion of future electric vehicles and charging demandsare developed using the law from historical development of China’s automobile market.In researches for impact of large-scale electric vehicles on power system operation,existing spatial and temporal distribution of electric vehicles are used to study the effectsof different penetrations of electric vehicle charging on load curve for distributionnetwork and urban power system. An electric bus charging model is built combined withengineering practice to study the effect of quick chargers on voltage flicker at different voltage levels in the distribution network, and work out the appropriate quick chargeraccessing voltage level. A smart fast charge station construction plan is proposed with theusage of decommissioned batteries to improve efficiency of transmission and distributionfacilities and reduce the distribution voltage flicker, too.In the study of optimal charging facilities planning, the simultaneously charging rateis proposed as the main indicator of charging stations planning and service abilityevaluating under private charging mode. For widely used battery exchange mode inpublic transportation, A battery charging-exchange station construction mode isproposed and corresponding optimal planning strategy is given. At last, actual statistics ofa city are taken as an example to determine the quantity of charge/exchange devices andbatteries in these stations which provide a reference for the actual planning of thesefacilities.