Reliability Analysis Of Distribution Network After Large-Scale Electric Vehicle Connected

Electric vehicle not only brings convenience to people’s life,but also brings great challenge to the reliability of distribution network.Especially during the peak period,the disorderly charging of electric vehicles will greatly increase the risk of distribution network operation.With the development of science and technology,intelligent distribution network and V2G(Vehicle-to-Grid,V2G)technology have been developed rapidly.V2 G technology is the interaction between electric vehicle and distribution network.The electric vehicle is charged in the valley period of the distribution network.In the peak period of the distribution network,the electric vehicle can choose to discharge to the distribution network if there is any remaining electricity.Compared to routine.Disordered charging and the application of V2 G technology can effectively improve the negative effects of disordered charging of large-scale electric vehicles on the distribution network.At the same time,V2 G technology also has the advantages of low operating cost and improving power efficiency.In this paper,taking the private electric vehicle as an example,combined with the commuting time of the residents and the charging and discharging characteristics of the electric vehicle,the charging and discharging model of the electric vehicle is established,and the influence of disorderly charging on the load of the distribution network is analyzed.The load of distribution network is analyzed by power flow calculation.The reliability model of distribution network considering the charging of electric vehicles is established,and the time series Monte Carlo method is chosen as the reliability analysis method of this subject.The influence of electric vehicle charging on the reliability index of distribution network is analyzed.An example shows that the unordered charging of a large-scale electric vehicle during the peak period will lead to overloading of the line.At the same time,with the electric vehicle access rules The mode is getting bigger and bigger,and the influence on the reliability of distribution network power supply is more and more big.Combined with the charging and discharging factors of electric vehicle,the discharge model of electric vehicle is established.Considering the electric vehicle as the distributed power supply to connect to the distribution network,two modes of operation are considered.The condition of island effect of electric vehicle under V2 G technology is analyzed.Based on V2 G technology,the reliability of distribution network is evaluated and compared with that of distribution network under disordered charging.The results show that the peak-valley difference can be effectively reduced and the peak-filling effect can be achieved by using the discharge characteristics of the electric vehicle battery under the V2 G technology.When electric vehicles of thesame size are connected to the distribution network,the V2 G charging mode is better than the conventional disordered charging mode.The reliability index of the power network has been improved to some extent,and the reliability of the distribution network has also been improved,At the same time,it also saves the investment cost of the power grid.