Avaliação dos impactos da recarga de veículos elétricos na vida útil de transformadores de distribuição

Abstract

The objective of this dissertation is to provide a comparative assessment of the impacts caused by charging practices of short-range and long-range electric vehicles under different power levels on life expectancy of distribution transformers. This research is based on the use of real data of residential energy consumption collected from the region of East Midlands, United Kingdom, as well as electric vehicle charging data collected through an experimental project also conducted in the United Kingdom. This study examines transformer hottest-spot temperature and evaluates the transformer accelerated aging factor that influences the equipment's lifespan according to the thermal model presented in IEEE Standard C57.91. As a result, this study reveals that the effects caused by long-range vehicles are more pronounced, as they charge at higher power level and the charging process is longer. As the penetration level of electric vehicles increases, transformer load and hottest-spot temperature increases, especially during winter season, where residential demand escalates. In the case of vehicles with 75 kWh, penetration levels starting from 30% already causes severe violations on transformer hottest-spot temperature, contributing to a reduction in the equipment's lifespan.