Time-Coupled Probabilistic Modelling of Electric Vehicle Charging Station Load and its Application

The load of electric vehicle charging station has large random fluctuation. It is of great significance for the security operation of distribution network to study the stochastic fluctuation characteristics of electric vehicle charging station load and establish a suitable probability characteristic model. A versatile distribution is used to fit the marginal distribution of a single-period charging station load. Considering the continuity of the charging behaviors of electric vehicles, the loads at adjacent periods are also correlated. Based on the characteristic of Kendall correlation coefficient, a D-vine Copula structure is constructed by Pair-Copula decomposition method to describe the correlation between loads at different time periods, and the joint probability distribution function is obtained. Scenario generation method based on Pair-Copula takes the correlation between the loads of the charging station at different time periods into account, so that the generated scenarios reflecting daily charging load changes are more typical. The daily load historical data of an actual electric vehicle charging station in 2017 is used to verify the effectiveness of the proposed method. An actual distribution network with electric vehicle charging station is taken as an example to illustrate the impact of different scenarios on the voltage of charging station access bus and the distribution network loss.