Effect of Electric Vehicle Chargers on the Harmonic Levels of a UK LV Electricity Distribution Network under Steady-State Cable Faults

Abstract

Despite the National Grid expecting the number of electric vehicles (EVs) on UK roads to increase to 35 million by 2050 (2019 data), the effect of electric vehicle chargers (EVCs) together with steady-state cable faults on the total harmonic distortion of the LV electricity distribution network (EDN) has not been considered. Therefore, the purpose of this paper is to investigate the effect that increased numbers of EVCs have on the steady-state voltage total harmonic distortion (THDv) of a UK LV EDN under steady-state cable fault arrangements. Using MATLAB simulations, the study analysed the steady-state THDv of a UK suburban residential LV EDN with increased numbers of EVCs under phase-to-phase and open-circuit network conditions. It was found that on the LV EDN studied, phase-to-phase conditions can increase the THDv of the network significantly. Under the test conditions, the LV EDN was found to no longer comply with the Engineering Recommendation G5/4-1. This paper recommends that the number of EVCs connected to LV EDNs should be restricted, or harmonic reducing technology implemented to observe compliance with the G5/4-1. Further analysis should be carried out to verify the simulation and to determine whether the harmonics observed have a noticeable effect on equipment connected to a residential network.