Influence of Electric Vehicle AC-Chargers on the Resonance Behavior of Domestic Distribution Grids

The ongoing integration of decentralized generation units and electric vehicles leads to an increasing number of power electronic inverters in distribution grids. These growing numbers of inverters can have a significant impact on the network harmonic impedance and therefore cause an alternation in resonances within the lower frequency range of 50 Hz to 2 kHz, where most harmonics are emitted. This paper deals in particular with the influence of electric vehicle AC-chargers. As analysis methods, the frequency scan and the resonance mode analysis are presented. Based on the resonance mode analysis, participation factors can be calculated that describe the impact of harmonics on specific nodes at certain resonance frequencies. As a case study, distribution grid data is adapted from a real grid topology of the city of Hanover, Germany.