A method for evaluating the impact of electric vehicle charging on transformer hotspot temperature

Abstract

The expected increasing market share of electric vehicles is a response to the combination of new technological developments, governmental financial control, and an attitude shift of residents to a more environmentally friendly lifestyle. The expected capacity required for charging, imposes changes in the load to the already existing components in the electric power grid. In order to continue managing these existing assets efficiently during this load change, it is important to evaluate the impact imposed by the battery charging.The transformer is considered as one of the most important components in the grid due to the potential severe and economic consequences upon failure; hence it is reasonable to begin an impact evaluation with this component. In areas where the grid is dimensioned close to the load limit, which often is set by transformer capacity limitations; an additional load from electric vehicles could force investments in the grid infrastructure.This paper presents a method to model electric vehicle charging load, based on uncontrolled and controlled charging scenarios, and furthermore, evaluate the impact caused by these charging scenarios on the distribution transformer hotspot temperature and loss of life using a thermal model. Index Terms-Charging profile, electric vehicle (EV), hotspot temperature, transformer loss of life.

Probabilistic Impact of Transportation Electrification on the Loss-of-Life of Distribution Transformers in the Presence of Rooftop Solar Photovoltaic

“…In [10], the transformer aging was estimated due to increasing PEV charging demand but without considering any solar PV penetration. Studies [11]- [14] investigated the impact of PEV charging on distribution transformer's overload but without taking into account the effect of rooftop solar PV, which may cause reverse power flow. Argade et al [15] studied the effect of charging PEV on the LOL taking into account the distribution transformer geographical location.…”

Review of Charging Load Modeling Strategies for Electric Vehicles: a Comparison of Grid-to-Vehicle Probabilistic Approaches

“…For example, with the penetration of EVs, it is not only evident that there is an increased electricity consumption in the power grid, along with the introduction of new load variations, but impacts have also been identified on transportation, manufacturing, and the economy (Li et al, 2019). These impacts depend on when EVs are connected for charging, where they are connected, and at which charging power (Grahn et al, 2011). Therefore, these factors must be considered in the operation, planning, and analysis of modern power grids such as active distribution networks or grid-connected microgrids (Alahyari et al, 2019).…”

“…unidirectional charging, bidirectional charging, uncontrolled charging, external charging strategies, and individual charging strategies (Grahn et al, 2011). Uncontrolled charging (UCC) means that EV users travel and park as they choose and connect their EVs when there is a need to recharge the battery.…”

The Concept of EV’s Intelligent Integrated Station and Its Energy Flow

“…Yilmaz et al [26] reviewed the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in EVs. Obviously, EVs will introduce additional load to the power system, and consequently, they can challenge power quality and reliability of power systems if their charging is not coordinated properly [27][28][29]. The impact of EVs on distribution networks can be determined by following aspects: driving patterns, charging characteristics, charge timing, and vehicle penetration, etc.…”