On the Integration of On-Route Fast Chargers for Battery Electric Buses

The electrification of a bus system using on-route fast chargers will require the installation of high-power chargers at bus stops. This work quantifies the impact of short duration high-power (pulse) charging demands of battery electric buses (BEBs) on power quality in terms of voltage flicker in electric distribution systems; hence, influencing the number of allowed charging events per hour. In addition, the introduced work investigates the minimum required electric distribution systems upgrades to mitigate such impact. The impact of charging is evaluated for both the IEEE-34 distribution test feeder and for a real distribution feeder, for which data was provided by an electric utility in Canada. The results show that the impact of intermittent charging demands of BEBs on power quality is highly affected by the system voltage of the feeder. Moreover, the concurrent charging of buses using multiple chargers connected to the same feeder can increase the voltage dip up to 15%, exceeding the voltage flicker borderline of irritation, which is unacceptable and will require a reduction of the number of allowed charging events per hour. However, the upgrade of distribution systems by adding voltage regulators and/or shunt capacitor banks can reduce the voltage dip to the permissible level, which will allow the hourly number of charging events required for regular operation of the bus system.