Plug-in electric vehicle collaborative charging for current unbalance minimization: Ant system optimization application

Plug-in electric vehicles (PEVs) are one of the solutions to reduce transportation dependency on oil. Nevertheless, uncoordinated charging in distribution low voltage (LV) networks can lead to local grid problems such as current unbalance and consequently voltage unbalance. In this paper, a combinatorial method based on Ant System (AS) optimization is proposed in order to minimize the current unbalance factor (CUF) by controlling the connection and disconnection of PEVs. The CUF is generated by PHEVs and neighboring residential loads. In addition a simulation environment is implemented to validate the performance of the AS method by benchmarking it against an Exhaustive Search approach. Results show that AS method gives satisfactory optimal solutions reducing the computation cost for scenarios having several hundred of PEVs.