Research On Coordinated Planning Of Electric Vehicle Charging Stations And The Active Distribution Network Considering Orderly Charging

In order to cope with the rapid development of electric vehicles,on one hand,charging facilities should be constructed to provide places for refueling.On the other,the current distribution network should be upgraded to bring sufficient and reliable power supply to these facilities.Therefore,the coordinated planning of charging facilities and the distribution network is required,so that a comprehensive and efficient charging network can be formed along with a well-functioning power network.Firstly,two orderly charging schemes of electric vehicles,namely time-of-use pricing and subsidy-based load shifting,is analyzed.The time-of-use pricing mode let customers adjust their time of charging spontaneously by classifying peak/flat/valley periods and assigning different prices.Based on the demand elasticity theory,load transfer between different types of period can be calculated and the new demand calculated.The subsidy-based load shifting is based on customer psychology theory.On the basis of time-of-use pricing scheme,contracts are signed with customers to provide them with subsidy and require them to shift their demand from peak hours to off-peak ones.Meanwhile,curve-fitting of actual charging data is performed using Gaussian functions to model the distribution of fast and slow charging throughout a day.After simulating the mass charging power,the influence brought by the orderly charging scheme is simulated and load-transferring cost calculated.Then,the coordinated planning model of charging stations and the distribution network considering orderly charging is constructed.By shifting charging demand from peak hours to the off-peak period,the maximum load during peak hours is reduced,as well as the nominal capacity of distribution lines,substations and charging stations.The planning model aims at minimizing the annualized total cost consisting of construction,operation and orderly charging.Constraints of the model include power flow,capacity,load demand,network topology,etc.The model is solved using MILP and verified through simulation of an 18-node distribution network.By paying customers some orderly charging cost,the investment cost of the whole network decreases,reducing the total planning cost.The planning result under different participation rates of the scheme is conducted and compared with the traditional method.Finally,load uncertainty and reliability of distribution network is added into the planning model.The fluctuation of load is modeled using multi-scenario technique,which reduces computational burden while ensuring the rationality of result.The reliability of charging station and distribution network is analyzed and reliability indexes of the charging station defined.Based on FEMA method,the reliability indices are calculated.The GA-MILP algorithm is proposed to solve the model.The effect bring about by the uncertainty and reliability is analyzed by comparing planning results with previous ones.