The impact of charging plug-in hybrid electric vehicles on residential distribution transformers

Plug-in hybrid electric vehicles are becoming more popular in smart grids. The batteries of these electric vehicles may be charged at home from a standard outlet. These extra electrical loads may have several adverse impacts on the distribution system. This paper proposes a comprehensive approach for evaluating the adverse impact of different levels of PHEV penetration on the loss of distribution transformers´ life. The proposed method is applied to a sample distribution transformer supplying residential customers. Obtained results show that nighttime charging of PHEVs has the least adverse impact on the loss of transformers´ life. This is while charging during evening peak hours can even cause a 900% increase in the transformer loss-of-life rate for a scenario with only 30% penetration of PHEVs.