Behavioral characterization of electric vehicle charging loads in a distribution power grid through modeling of battery chargers

Plug-in Electric Vehicle (PEV) is a new atypical

load in power systems. In future, PEV load will play a significant

role in the distribution grids. This integrated load into the power

grid may overload the system components, increase power losses

and may violate system constraints. Currently, the most common

method of Electric Vehicle (EV) modeling is to consider the EV

loads as constant power elements without considering the voltage

dependency of EV charging system during state of charges

(SOC). EV load demand cannot be considered as a constant

power, as modeling as a constant power load will not provide

accurate information about the behavior of charging system

during charging process. As several research projects on smart

grids are now looking into realistic models representing the

realistic behavior of an EV loads, this paper proposes a

methodology for modeling of EV charger integrated to an

electricity grid in order to understand the impacts of EV

charging load. A charging system was designed to capture the

EV load behavior and extract the coefficients of the EV ZIP load

model. A comparative study was carried out with different types

of load models. The results indicate that the assumptions of load

demand as a constant power to analysis the effect of PEVs on

power grid would not be effective in real time application of

PEVs.