Optimal charging of electric vehicles in low-voltage distribution systems

Advances in the development of electric vehicles,
along with policy incentives will see a wider uptake of this
technology in the transport sector in future years. However, the
widespread adoption of electric vehicles could lead to adverse
effects on the power system, especially for existing distribution
networks. These effects would include excessive voltage drops and
overloading of network components, which occur mainly during
periods of simultaneous charging of large numbers of electric
vehicles. This paper demonstrates how controlling the rate at
which electric vehicles charge can lead to better utilisation of
existing networks. A technique based on linear programming is
employed, which determines the optimal charging rate for each
electric vehicle in order to maximise the total power that can be
delivered to the vehicles while operating within network limits.
The technique is tested on a section of residential distribution
network. Results show that, by controlling the charging rate of
individual vehicles, high penetrations can be accommodated on
existing residential networks with little or no need for upgrading
network infrastructure.