Abstract Phase unbalance is a common issue encountered in LV electricity distribution networks, caused by uneven allocation of single-phase loads among phases. This paper analyses a part of a real LV distribution network, situated in Bosnia and Herzegovina. The impact of single-phase customers and single-phase charging of electric vehicles was analysed. To reduce unbalance and improve the voltage profiles, Phase Balance Optimization in DIgSILENT PowerFactory software was performed in six scenarios with different customer and electric vehicle unbalance. The goal was to find a method with the least number of changes in the customer and electric vehicle phase connection that fits within defined limits of voltage variations and voltage unbalance of a European norm for power quality (EN 50160). Results showed that all analysed scenarios were improved, with reference to voltage variation and voltage unbalance values, and were found acceptable by the limits from standard EN 50160.

Electric vehicles (EVs) retain the focus of the public attention because of the constant development and promotion of their technology and global warming awareness. Their integration is expected to experience an exponential rise along with new challenges for the existing networks. Simultaneous and unregulated charging of a large fleet of EVs increasingly burdens the power system and negatively affects the power quality parameters, especially during the daily peak-period. The paper analyses the power quality analysis of a low-voltage distribution network in Bosnia and Herzegovina. Different EV types are investigated, such as Mitsubishi i-MiEV, Renault ZOE, Volkswagen e-Golf, and Tesla X, to determine their impact on harmonic voltages impact for three EV penetration levels: 10%, 20% and 50%. Wallbox charging mode is also investigated. The results are evaluated compliably with the European power-quality standard EN 50160. Results show that none of the analyzed EV penetration scenarios violate the permissible harmonic voltage limits, except for the 50% EV penetration scenario with wallbox charging.