Impact of Reactive Power from Public Electric Vehicle Stations on Transformer Aging and Active Energy Losses

Abstract

Climate change at the global level has accelerated the energy transition around the world. With the aim of reducing CO2 emissions, the paradigm of using electric vehicles (EVs) has been globally accepted. The impact of EVs and their integration into the energy system is vital for accepting the increasing number of EVs. Considering the way the modern energy system functions, the role of EVs in the system may vary. A methodology for analyzing the impact of reactive power from public electric vehicle charging stations (EVCSs) on two main indicators of the distribution system is proposed as follows: globally, referring to active power losses, and locally, referring to transformer aging. This paper indicates that there is an optimal value of reactive power coming from EV chargers at EVCSs by which active energy losses and transformer aging are reduced. The proposed methodology is based on relevant models for calculating power flows and transformer aging and appropriately takes into consideration the stochastic nature of EV charging demand.

Keywords

• electric vehicles
• electric vehicle charging stations
• active power losses
• power distribution transformers
• thermal aging
• reactive power