Plug-in hybrid electric vehicle (PHEV) technology provides one of the most promising solutions to tackle the threatening challenges such as air pollution in urban areas. Dramatic increases in the number of PHEVs could have major impacts on power system operations because of their high electricity demand. From the distribution system operator facet, distribution system congestion during PHEVs' charging is an economic and security concern. It is, therefore, necessary to investigate the effects of widespread using of PHEVs on the performance of distribution networks. In this paper, PHEV characteristics are exactly studied and a comprehensive model for investigation of PHEV impacts is achieved. The results would likely demonstrate distribution congestion arising from using PHEVs. Controlled charging of PHEVs is a possible solution to the distribution congestion problem. In this work, optimal charging algorithm is developed which minimizes the electrical charging payment of customers. The optimization problem is solved by energy schedulers in each home. The output of the problem is the charging level for PHEVs in each period of the scheduling time.
Results illustrate that due to noticeable likeness between the load behavior and tariffs, minimizing customer cost would likely lead to shave peak load and prevent distribution congestion.