Decoupling Analysis Of The Impacts Of Electric Vehicle Charging Load On Grid And Research On The Intelligent Charging Strategy

With the seriousness of environment and the shortage of energy,electric vehicles(EVs)with clean electric energy power will be growing rapidly.The impacts of large scale EVs charging on power grid and coordinated control have drawn worldwide attention.Therefore,the impacts of EVs charging on power grid and control strategy of intelligent charging are studied in this paper.The main research contents are as follows:(1)The main factors affecting EVs charging are studied.Analysis model of the travelling laws of EVs is researched based on the statistics by the U.S.Department of Transportion.The calculation method of uncoordinated charging load is improved based on the statistical model and Monte Carlo method.Then,calculation process is presented.(2)The article proposes a decoupling analysis method which studies charging load and normal load independently and then carries out an integrated analysis with the power grid.The characteristics of EVs charging load which include average,deviation,fluctuating power of charging load and regional unbalance are proposed.So that we get the fundamental laws of characteristics of EVs charging load changing with the number of vehicles and charging power.After that,the impacts of EVs in a scene of large penetration rate on power grid at all levels in China are studied and the possibility of main problems happening is got.(3)The control strategy of charging which determines the optimization goals and constraints is proposed based on the time-of-use price.Then control algorithm of intelligent charging which includes outer ordering and inner ordering is presented.So that selected EVs are integrated into power grid to achieve the coordinated charging and reduce the bad influence on power grid.(4)The control strategy of intelligent charging based on the time-of-use price is simulated which is based on the distribution system by 380 V.Load curves,load ratios of transformers,deviation of node voltage and network loss under coordinated charging are studied and contrasted to that under uncoordinated charging.The results show that the control strategy of intelligent charging can achieve load shift,reduce the bad influence on power grid and improve the operating economy of network.