Impact of Electric Vehicles on Power Grids During Network Faults

As electric vehicles (EVs) gain popularity, consumers are increasingly adopting them as an alternative to traditional fossil fuel-based internal combustion engine-driven vehicles. EV chargers integrate with distribution networks via power electronic interfaces, offering significant control and operational flexibility. The industry is quickly adapting to this novel load interface, and this paper address the key blind spots in the analysis of the associated impacts. Four EVs were physically tested under various network fault conditions using a grid simulator supply interface, and their fault ride-through (FRT) performances have been characterised. Our findings are that faults causing undervoltage at or below 0.3 pu can lead to EVs either ceasing charging for between ~2 – 10 seconds, or locking out completely. Using the Tasmanian power system as a test case with low system strength and modest EV charger penetration, we simulate a double-line-to-ground transmission fault to assess the impact of this FRT behaviour. The aggregation of EV fault-responses yielded a resultant successive over-frequency and under-frequency of 50.78 and 49.22 Hz respectively, for the scenario with the most demonstrable impact from on-charge EVs. These results clearly illustrate the impact of EVs on power grids during network faults, whilst providing a genuine resource for industry to undertake further simulations.