The integration of the electric vehicles to the distribution network means an additional and unpredictable consumption for the system operator. High peak powers of the charging stations in case of unplanned charging affect the stability of power system operation, thus it is important that the influence of the electric vehicles is well defined.
The aim of this thesis is to define the impact of the electric vehicles on low-voltage (LV) distribution networks and the associated network parameters. Furthermore, the elements of the low-voltage network and associated models in simulation environments are also described, as well as different types of electric vehicles, their charging methods and the way they may behave as either active or passive loads in a network.
The impact analysis of the implementation of electric vehicles was carried out on a realistic model of a low-voltage network with real annual consumption data for 27 household electricity consumers. In different cases, a 7-kW electric vehicle charging station was implemented, which operated and charged electric vehicles in the afternoon and evening.
The second part of this thesis presents a scenario approach and a simulation environment for analyzing the impact of electric vehicles on the distribution network. A simulation interval of one week in the summer term was selected for the analysis. The simulations were performed in OpenDSS and MATLAB software environments. The possibility of interaction between the programs provides a more precise way of analyzing the data, a faster and more thorough analysis, and a graphical representation of the results obtained.
The simulation results capture power flows through the SN / NN transformer, voltage conditions, and losses in the low-voltage network. Electric vehicles have shown to have a major impact on peak power flows resulting from the uncoordinated charging regime. There are large voltage drops and, consequently, greater losses in electricity transmission. A high number of electric vehicles could require the inclusion of a larger transformer to ensure a more stable system operation.