Seasonal Effects of Electric Vehicle Charging on the Aging of Distribution Transformers

Abstract

Large-scale adoption of electric vehicles (EVs) will be accompanied by several technical, financial and environmental benefits. However, high penetration of EVs in residential neighborhoods is expected to overburden the local distribution network. Unregulated EV charging has the potential to reduce the lifespan of network equipment, most notably the distribution transformer. The loss of life of a transformer is a function of its internal temperature, which in turn depends on the kVA loading and ambient temperature. Transformer loading is influenced by the level of EV penetration while the ambient temperature varies seasonally. This paper examines the impact of domestic EV charging on the aging of a distribution transformer under multiple penetration levels during summer and winter. The transformer's thermal model is utilized to determine its internal temperature and the rate of aging under different loading levels. The simulation results clearly exhibit the variation in transformer aging with EV deployment under different seasons.