Evaluating the Impact of EVs and Heat Pumps on Primary-Secondary Distribution Systems Using Real-World Data

The increasing adoption of electric vehicles (EVs) and heat pumps (HPs) is reshaping residential electricity consumption, posing significant challenges for distribution grid utilities, particularly regarding transformer overloading. This paper explores the impacts of EV charging and HP integration on distribution grids, taking into account these additional loads alongside typical residential demands. The study focuses on the service transformer (ST) overloading hours across various seasons, examining the effects of EV and HP penetration on the primary-secondary distribution system. To conduct this study, we extracted probability distributions that characterize EV charging behavior and the consumption profiles of residential customers with and without HPs. All data used in this investigation were real-world measurements collected from various utilities in the Midwest region of the USA. We developed a sampling technique to generate EV charging and residential customer consumption profiles, which were then utilized for Monte Carlo (MC) simulations. ST overloading is identified across various seasons for different penetration levels of EVs and HPs. Finally, the periods of frequent ST overloading are determined to guide utilities in defining tariff for different times of use.