In the last couple of years, the evolution of plug-in electric cars has contributed to an increasing need of well-built charging infrastructure. This does not only require that the fair amount of charging stations needs to match the increasing demand, but the growing amount of charging station could also affect the power quality in the grid itself due to the technology used today.
The objective of the first part of the project was to deliver a complete installation plan and project basis of two AC charging stations for electric vehicles, planned in the city of Kungälv. The second part of the project was focused on studying the effects of DC fast charging of electric vehicles, with power quality in mind. This study was based on readings obtained from measuring the power quality at an existing DC fast charging station in Kungälv, as well as available publications within the area of the subject. The project planning was conducted in regards to Swedish standards and regulations, as well as to the instructions and expectations of the client, Kungälv Energi. The result was compiled and handed over to the client during the final part of the project. The resulting document contained information regarding installation, material and placement as well as approximate cost calculations.
The power quality study was carried out on a currently installed fast charging station located in the city of Kungälv, using power quality measuring instruments provided by Kungälv Energi and Metrum Sweden AB. The result was a power quality report, compiled according to Swedish Energy Markets Inspectorate, where all requirements concerning power quality were met. The data was also analyzed manually, to further investigate the effects of DC fast charging. The study shows no immediate signs of negative impact of the power quality in the nearby grid caused by the fast charging stations within the project. There were signs of harmonics caused by the charging stations, but the presence was considered low. The usage frequency is however a major factor when investigating the power quality affection of the charging station. This results in a conclusion that is not generally applicable.