The Impact of Electric Vehicles on Low Voltage Grids: A Case Study of Berlin

Replacing fossil-fueled vehicles with electric vehicles (EVs) poses new challenges for public distribution networks. In order to accommodate these new loads in current grid extension planning, distribution system operators (DSOs) have to consider various EV penetration scenarios. This involves long planning and investment cycles, on the one hand, and several dissemination projections on the other. In this case study, the potential impact of EVs on transformer, cable sections and power quality in two representative urban and suburban low-voltage (LV) grids are investigated. For that, simulation studies based on real grid topologies are employed. Two different approaches to modelling EV charging concurrency behavior in the urban and suburban grids are applied. The study finds that when concurrency in charging is considered and EVs comply with harmonics regulation standards, Berlin's LV grids can accomodate very high penetrations of even 50% and 100% without the need for reinforcement. Penetrations below 30%, however, may lead to overloading or unacceptable power quality. This may occur if EVs do not comply with current standards or mobility and charging patterns deviate significantly from the proposed approaches.