Evaluation of power-quality field measurements of an electric bus charging station using remote monitoring systems

Vehicle electrification has become an important measure for greenhouse gas reduction in many countries worldwide. Regardless of what type of electric vehicles (EVs), the on-board battery must be charged via a charger or charging station. In the future, when large numbers of EV chargers or charging stations are connected to distribution systems, there will be a degree of influence on the system operation and power quality. This paper aims for presenting the methodology and results for evaluation of power-quality field measurements of an electric bus charging station in Taiwan by using remote monitoring systems. The charging station under study has 11 charging poles, including 2 fast charging and 9 slow charging poles. The power quality issues including electrical power measurements, voltage flickers, harmonic distortion, and three-phase unbalance are discussed. Power quality measurements of the high-voltage customer closing to the station are also collected and evaluated. Test results show that with the proposed method the power quality of electric bus charging stations can be effectively monitored and evaluated. The results of this study can provide utilities with useful information regarding grid planning against significant electric bus penetration.