Modeling of Load Demand Due to EV Battery Charging in Distribution Systems

Abstract

This paper presents a methodology for modeling and analyzing the load demand in a distribution system due to electric vehicle (EV) battery charging. Following a brief introduction to the common types of EV batteries and their charging characteristics, an analytical solution for predicting the EV charging load is developed. The method is stochastically formulated so as to account for the stochastic nature of the start time of individual battery charging and the initial battery state-of-charge. A comparative study is carried out by simulating four EV charging scenarios, i.e., uncontrolled domestic charging, uncontrolled off-peak domestic charging, "smart" domestic charging and uncontrolled public charging-commuters capable of recharging at the workplace. The proposed four EVs charging scenarios take into account the expected future changes to the electricity tariffs in the electricity market place and appropriate regulation of EVs battery charging loads. A typical U.K. distribution system is adopted as an example. The time-series data of EV charging loads is taken from two commercially available EV batteries: lead-acid and lithium-ion. Results show that a 10% market penetration of EVs in the studied system would result in an increase in daily peak demand by up to 17.9%, while a 20% level of EV penetration would lead to a 35.8% increase in peak load, for the scenario of uncontrolled domestic charging-the "worst-case" scenario.

Demand profile study of battery electric vehicle under different charging options

“…Modeling the demand of an EV acting as a flexible load in the Mr. Marra power system represents an area which was not addressed until few years ago. In [6] the authors proposed a methodology for modeling EV as an additional load in the distribution grid. In the work, it is considered that the charging operation can either take place in uncoordinated manner or it can be intelligently managed during off-peak electricity hours.…”

A Comprehensive Study of Key Electric Vehicle (EV) Components, Technologies, Challenges, Impacts, and Future Direction of Development

“…Charging without any concern to the time of drawing power from the grid is denoted as uncoordinated charging, uncontrolled charging or dumb charging [124,125]. This can lead to the addition of EV load in peak hours which can cause load unbalance, shortage of energy, instability, decrease in reliability and degradation of power quality [126,123]. In case of the modified IEEE 23kV distribution system, penetration of EVs can deviate voltage below the 0.9 p.u.…”

A preventive control strategy for static voltage stability based on an efficient power plant model of electric vehicles

“…Their proportions in UK are 61 %, 30 % and 9 %, respectively [27]. This classification is used to obtain EV daily travelling distance and time.…”

“…Based on the use of transportation (HBW, HBO and NHB), daily travelling distance d follows a normal distribution, which is expressed as [27].…”

“…Hybrid Charging: Hybrid charging is a charging strategy with 50 % of the EVs adopting dumb charging and the remaining 50 % following smart charging. Assuming SOC drops linearly with the travelling distance [27], K SOC 0 is determined as…”