1 AIT Asian Institute of Technology

Optimal scheduling of the EV charging for the mitigation of overload and unbalanced three-phase load conditions on the distribution transformer

AuthorIttiporn Sornprasit
Call NumberAIT Thesis no.SE-24-02
Subject(s)Electric vehicles--Thailand
Electric vehicles--Government policy--Thailand
Electric power distribution--Thailand
Electric vehicles--Power supply--Thailand
NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Sustainable Energy Transition
PublisherAsian Institute of Technology
AbstractThe global trend of EVs is increasing, as well as in Thailand. As EV penetration increases, single-phase residential chargers continue to account for most charging infrastructure. The additional load from residential EVs could generate peak demand that might affect the overload on the distribution transformer. In addition, the unplanned distributed single-phase chargers could increase the three-phase unbalanced load. Firstly, this research aims to study the impact of EV charging on the distribution transformer and Three-phase unbalanced load in the case of Overload. Then, EV charging scheduling techniques are developed to avoid overload of the parallel distribution transformer to mitigate three-phase load imbalances. To make the outcome more realistic, the model is simulated based on the actual low voltage distribution grid of the Provincial Electricity Authority (PEA) in Thailand, and The EV charging profile would be generated by a stochastic process based on data from National Household Travel Survey (NTHS 2017). The EV scheduling program is established by two-step optimization developed by GAMS software. The first objective is phase unbalance mitigation. Then, the EV charging power was scheduled in step two optimization based on the priced-based objective. The individual electric vehicle charging time from the scheduling program was simulated in the system by coordinating Python API and DIgSILENT power factory software. In conclusion, the outcomes from the simulation show the overload on the distribution transformer and the increase of three-phase unbalanced factors in a random charging scheme. After implementing the scheduling program, the simulation indicates no overload on the distribution transformer along the simulation. In terms of imbalance, the fluctuation of three-phase imbalance factors has been improved. As a result, the overall losses in the system with an EV scheduling program are lower than EVs charging scheme without a scheduling program.
Year2024
TypeThesis
SchoolSchool of Environment, Resources, and Development
DepartmentDepartment of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC))
Academic Program/FoSSustainable Energy Transition (SE)
Chairperson(s)Singh, Jai Govind
Examination Committee(s)Weerakorn Ongsakul;Ekbordin Winijkul
Scholarship Donor(s)PEA-AIT Education Cooperation Project;AIT Scholarship
DegreeThesis (M. Eng.) - Asian Institute of Technology, 2024


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