| In order to cope with the "double carbon" target,China has put forward the development strategy of building a new power system with new energy as the main body,in this context,vigorously developing new energy vehicle(EV)has become an important means to realize the clean energy consumption side.In recent years,the Chinese market has become the global leader in the growth rate of EV sales,and as the number of EV ownership climbs year by year,the large-scale use of EVs has become an inevitable trend of electric energy substitution and green transportation development.However,with the increasing number of EVs,their charging load will put greater pressure on the distribution network,which may lead to power quality problems such as overload of distribution equipment and uneven distribution of tide.The emergence of incremental distribution network provides a new option to cope with the high proportion of EV access.To this end,this paper conducts an in-depth study on the impact of EV cluster access on the demand of urban incremental distribution grid.Firstly,the paper constructs an EV charging load prediction model based on Monte Carlo simulation algorithm.Taking an incremental distribution network pilot city as the research object,the Monte Carlo simulation algorithm was used to randomly extract the starting charging time and daily mileage of EVs,then this paper calculates the charging time and battery status at the beginning of charging,and finally obtains the charging load curve of buses,taxis and commuter private cars in the city.Secondly,the paper constructs a prediction model for the electricity demand of urban distribution network considering the access of EVs.Based on the system dynamics method,relevant variables such as residential basic electricity load,EV charging load,maximum load factor and power factor of different functional areas are introduced into the model,and the simulation analysis is carried out with the system dynamics simulation software Vensim PLE to obtain the comprehensive load data of distribution networks in different functional areas and the comprehensive load fluctuation of distribution networks in the central city.Finally,this paper constructs a capacity planning model for the city’s incremental distribution network.The combination of "orderly charging control+new distribution transformer" is used to analyze the control cost of orderly charging of EVs and the total cost of new distribution transformer in the whole life cycle,and the combination decision optimization model of the city’s incremental distribution network is constructed with the objective of minimizing the total cost.The model is solved with the help of MATLAB compiler software by setting constraints such as power constraint of distribution network,capacity constraint of incremental distribution network and cost constraint of EV users.And finally the incremental capacity demand of the urban distribution network under the optimal solution is obtained.The results of this study show that there is a large peak-to-valley difference in the distribution of EV charging load in the city,and the cluster access of EVs will aggravate the peak electricity demand of the distribution network in the central city,while the measures to guide the orderly charging of EVs will have little effect on the overall electricity load of the distribution network.New distribution transformer capacity is needed to meet the residential electricity demand.Through the research of this paper,the comprehensive electricity demand situation of the distribution network and the demand forecast data of the urban incremental distribution network under the optimal solution can guide the distribution network system to make timely response according to the fluctuation of residential electricity load,so as to improve the comprehensive energy utilization efficiency and avoid energy wastage due to over-concentrated electricity load,and to further rationalize the arrangement of distribution transformer facilities and EV charging facilities,thus improving the intelligent control and optimal operation of the urban incremental distribution network.It can further rationalize distribution transformer facilities and EV charging facilities,thus improving the grid connection of EVs,realizing intelligent control and optimal operation of the power system,and providing a reference for the rational planning of future incremental distribution grids in cities. |
