Research On The Economic Dispatch Of Power Grid Considering Charging And Discharging Of Electric Vehicles

With the rapid development of the global economy,the environment pollution and energycrisis has been becoming the global problems.As a kind of clear transportation tools,theelectric vehicles has already come to innumerable homes，Electric instead of petrol,zerorelease and low noise are the main features of the electric vehicles.Thus the development ofthe electric vehicles industry has become an important measure to relieve the problems ofglobal energy crisis and environment pollution.As the same time, it is also the organiccomposition in the construction of the intelligent power grid.Plug-in hybrid electric vehicles (PHEVs) can be considered as electric loads whencharging, but also can behave as distributed generation resources when discharging in the idlestate. The connection of large-scale PHEVs to the power grid will impose a series of newproblems to the economic and safe operation of the electric power systems. The paper hasfirstly introduced the effects on the power grid after the electric vehicles integrate into it andalso recommended the factors which influence the dispatch of the electric vehicles.Then thepaper has elaborated some measures to work out the dynamic economic dispatch model of theelectric power system. Traditional optimization methods contain dynamic programming andLagrange relaxation method, while the intelligent optimization methods such as inheritancearithmetics and particle population arithmetics can also solve these problems effectively. Atlast, the differential evolution is introduced and some improvement measures are put forward.This paper formulated a dynamic economic dispatch model which the social total costs(the unit coal cost, exhaust emissions, the economic effects of PHEVs users)were selected asthe minimum objective functions and the corresponding constraints were considered. TheBi-population differential evolution with elitist strategy was implemented aiming at thiscomplex model thus extracting the best dispatch scheme. The proposed power dispatchapproach was tested on a ten-unit system. The results show that with reasonable generationschedule, large-scale integration of PHEVs into power gird can provide services like peak-load shaving and spinning reserves on day load.