Relieving the pressure of electric vehicle battery charging on distribution transformer via particle swarm optimization method

In this paper, a stochastic model of plug-in hybrid electric vehicle (PHEV) is developed in Matlab to investigate its impact on distribution transformer. Two types of PHEVs are included in this model, sedan and SUV. These two types of PHEV share the same charging schedule, but possess different charging characteristics. Charging power, Full-charge time for example. If dumb charging method (V0G) is applied, that will surely result in a load peak in the evening. From the simulation results, it is proven that this scale of load peak will lead to the increase of loss of life (LOL) of distribution transformer. To mitigate the load peak, particle swarm optimization method is performed to reschedule the charging pattern of each PHEV. Eventually, the LOL of distribution transformer is minimized with smoother charging load curve after optimization.