Research On The Method Of Locating And Sizing Of Charging Facilities Under The Integration Of "Vehicle-Road-Electricity" Three Networks

In recent years,in order to solve the problems of environmental pollution and energy crisis,the state has vigorously promoted the use of clean energy and electric vehicles.However,with the expansion of the scale of electric vehicles and the surge of charging demand,there is a mismatch between charging demand and charging facilities;at the same time,the convergence of charging loads becomes an important factor affecting the safe operation of the distribution network.At this present stage,studies rarely consider the impact on the distribution network when planning charging stations,but the three networks of "vehicle-road-electricity" are closely integrated.Therefore,this thesis studies how to select and determine the location of charging stations in the "vehicle-roadelectricity" three networks.Considering that electric vehicles are the intermediate link,the operating characteristics are related to the transportation network,a "vehicle-road-electricity" system model is established in this thesis.Against this background,the temporal and spatial distribution of electric vehicles charging demand is predicted.Firstly,the Gaussian mixture model is used to fit the relevant feature quantities in the travel chain,and the maximum likelihood estimation method is used to solve the parameters in the model.Secondly,taking electric taxis and electric private cars as research objects,the daily travel process is analyzed,and the spatio-temporal transfer behavior of electric vehicle travel is simulated by using Monte Carlo sampling combined with the travel chain,and the time and location of charging demand are predicted.Aiming at the mismatch between charging demand and charging facilities and the problem that the operation of charging stations reduces the operational stability of the distribution system,this thesis proposes a charging station planning method based on distribution network voltage and network loss.A charging station site selection and capacity optimization model is established,taking the minimization of user loss cost,investor cost,voltage offset and power loss as the objective functions,consider the user waiting time,device utilization rate and node voltage offset as constraint conditions.The combinatorial empowerment method based on game theory is used to calculate the weights of each target value in the planning scheme,and the target value is normalized and linearly combined with the weight to form the fitness value,and the alternative scheme is optimized.Example analysis shows that the planning scheme solves the problem of long distance and long waiting time in the station from the perspective of the vehicle network,solves the problem of unreasonable construction of charging station and low utilization rate of the device from the perspective of the road network,solves the problem of serious network loss and large voltage offset from the perspective of the power grid,and realizes the integration of the "vehicle-road-electricity" three networks.With the increase of photovoltaic grid-connected capacity,the impact of photovoltaic grid-connected on the distribution system needs to be taken into account in the planning process of charging stations.Firstly,the uncertainty model of photovoltaic output is established,and the influence of the photovoltaic installation position and capacity on system voltage and network loss is analyzed.Secondly,considering the different situations of whether there is photovoltaic installation in the planning area,a charging station planning model considering the impact of photovoltaics and a joint planning model between charging stations and distributed photovoltaics are established.Example analysis shows that the model established in this thesis can improve the utilization rate of the device and reduce the total social cost under the premise of meeting the charging needs of users,while improving the utilization rate of photovoltaics in the distribution system,reducing the voltage offset of the distribution system,and improving the operating economy.