Optimal transformer sizing with the presence of electric vehicle charging

The loss of life of distribution transformers has become a significant concern with the prevalence of charging electric vehicles. One alternative is to increase the transformer rating. Due to no-load losses associated with a higher transformer rating and greater limited loading on a transformer (mainly between 5:00 and 11:00 pm), a method is proposed to optimize the transformer rating. In this work, a secondary-distribution transformer with no-load losses is minimized while limiting the acceleration of the transformer loss of life. An example is shown to illustrate the validity of this model. Both controlled and uncontrolled charging options are considered to analyze the importance of charging diversity on transformer sizing.