Toward Mitigating Electric Vehicles Impact on Power System: A Planning Approach

With the rapid growth of electric vehicles, power systems would face serious difficulties to supply the excessive electricity demand in the near future. In this paper, a bilevel planning method is introduced to prevent the environmental and technical issues that the introduction of electric vehicles may cause for electricity grids. The idea of this method is to employ the differences between EV types and optimally distribute them within the power system. The planning objective, modeled by the upper-level problem, is to minimize the total CO2. This upper-level problem is constrained by a lower-level optimal power flow. The model is reduced to a single-level convex optimization problem using the duality theory. The importance of decreasing urban area emission is also considered in this model. The IEEE RTS 24 system, and real world vehicle specifications is used to demonstrate the capability of the proposed method. Results suggest that for low daily trip distances, the best option depends on the priority of urban area emission reduction. On the other hand, for higher distances, the plug-in types would lead to lower total emissions. Keywords—Bilevel model, CO2 emissions, Duality theroy, Planning, Electric Vehicle NOTATION Indices and Sets i,j Index of system buses t Index of time slots u Index of generating units b Index of blocks of generating units heat rate l Index of transmission lines w Index of scenarios B Set of system buses T Set of time slots G Set of generation units Bu Set of blocks of generating units heat rate of unit u W Set of scenarios Variables xi,phev Number of PHEVs in bus i xi,hev Number of HEVs in bus i xi,pev Number of PEVs in bus i Pg Total amount of power generation of units F Transmission line power δ Voltage angle of system buses EVload Total load of EV charging at bus Constants and input data d Daily trip distance for all vehicles demandpev Amount of electricity used by a PEV in one-day trips demandphev Amount of electricity used by a PHEV in one-day trips AER All-electric range of PHEVs bcpev Battery capacity of PEVs bcphev Battery capacity of PHEVs Cpev PEV charger’s rated power Cphev PHEV charger’s rated power Tpev Needed time to fully charge a PEV Tphev Needed time to fully charge a PHEV Lpev Load of charging a PEV in every time slot Lphev Load of charging a PHEV in every time slot ephev Total CO2 emitted in one day from a PHEV ehev Total CO2 emitted in one day from an HEV CPKhev CO2 emission rate of HEVs CPKphev CO2 emission rate of PHEVs while using electricity B Matrix of transmission line Susceptances load Load of system buses M Matrix of mapping the generation units to system buses N Specified total number of vehicles Sb Base power of the system H Incremental heat rate value in every step eu CO2 emission rate of unit α Importance factor for urban area emission Pg Unit minimum production limit Mohammadreza Barazesh*, Javad Saebi**, and Mohammad Hossein Javidi D. B.*** * Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran, mr.Barazesh@stu.um.ac.ir ** Faculty of Engineering, University of Bojnord, Bojnord, Iran, j-saebi@ub.ac.ir *** Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran, h-javidi@um.ac.ir Pg Unit maximum production limit Y Line susceptance s(l) Sending end of transmission line r(l) Receiving end of transmission line F Transmission line minimum power limit F Transmission line maximum power limit fc Fuel cost of generation units Ω Probability of every scenario