Evaluation of grid relieving measures for integrating electric vehicles in a suburban low-voltage grid

Abstract

Within this study the impacts of future electric vehicle penetrations on the low-voltage level are analyzed. Therefore, the need for grid expansions is prematurely identified based on a suburban grid, operated by the Austrian distribution system operator Energienetze Steiermark GmbH. The future development of electromobility-induced grid effects is demonstrated by simulating several electric vehicle penetration rates. Additionally, grid restrictions are counteracted by analyzing grid- and user-controlled measures. The investigated suburban low-voltage grid could face inadmissible voltage range deviations per EN 50160 at an EV-penetration of only 10 %. Moreover, an increased share of electric vehicles leads to critical voltage unbalances (around 40 % EV) and thermal overloads (around 20 % EV). This study shows in addition, that voltage deviations are reduced significantly by several measures. Furthermore, grid expansions can be avoided by a charging infrastructure equipped with voltage-dependent active power control, or switching to three-phase charging with reduced power. These measures prevent inadmissible voltage range deviations and voltage unbalances as well as critical thermal conditions even at an 80 % electromobility penetration.