Applications of probability model to analyze the effects of electric vehicle chargers on distribution transformers

Author(s):  
Jason M. Sexauer ◽  
Kerry D. McBee ◽  
Kelly A. Bloch
2020 ◽  
Author(s):  
Marcel A. A. Viegas ◽  
Carlos Tavares da C. Jr.

This paper proposes the design and dynamic analysis of a possible topology of Electric Vehicle Fast Charging Station (EVFCS), which interconnects Photovoltaic Generator (PV); Stationary Batteries (SB); DC Bus; Electric Vehicle (EV); Power Switches; DC-DC Power Converters (Buck, Boost, and Bidirectional DC-DC Converter); Bidirectional AC-DC Converter; High Frequency Transformer (HFT); Matrix Converter (MC) and LCL Filter, with the possibility of connecting to the Utility Grid. The Stationary Battery will be charged slowly through the Photovoltaic System in the morning and afternoon hours and by the Utility Grid at night. Later, the Stationary Batteries will be discharged and will charge the Electric Vehicle Battery quickly (about 20-30 minutes) through a Bidirectional DC-DC Converter and through the Utility Grid, but with an effort much less to process high power in short time intervals in the distribution transformers. The power and control projects of the system were performed through calculations and validated by performing simulations. The simulations will be done in MATLAB / Simulink software. Three operating scenarios will be created, where the use or not of the Utility Grid will be analyzed, according to the intermittent of the Photovoltaic Generator, the State-of-Charge (SOC) of the Stationary Batteries and the Electric Vehicle. For this, there will be the management of the power flows that will be performed by Power Switches. The results indicate the effectiveness of the proposed strategies.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3486
Author(s):  
Teguh Kurniawan ◽  
Craig A. Baguley ◽  
Udaya K. Madawala ◽  
Suwarno Suwarno ◽  
Nanang Hariyanto ◽  
...  

Distribution networks with high electric vehicle (EV) penetration levels can experience transformer overloading and voltage instability issues. A charge scheduling approach is proposed to mitigate against these issues that suits smart home settings in residential areas. It comprises measurement systems located at distribution transformers that communicate directly with fuzzy logic controller (FLC) systems embedded within EV supply equipment (EVSE). This realizes a reduction in data processing requirements compared to more centralized control approaches, which is advantageous for distribution networks with large numbers of transformers and EV scheduling requests. A case study employing the proposed approach is presented. Realistic driver behavior patterns, EV types, and multivariate probabilistic modeling were used to estimate EV charging demands, daily travel mileage, and plug-in times. A Monte Carlo simulation approach was developed to obtain EV charging loads. The effectiveness of mitigation in terms of reducing distribution transformer peak load levels and losses, as well as improving voltage stability is demonstrated for a distribution network in Jakarta, Indonesia.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 210183-210193
Author(s):  
Pravakar Pradhan ◽  
Iftekhar Ahmad ◽  
Daryoush Habibi ◽  
Ganesh Kothapalli ◽  
Mohammad A. S. Masoum

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3257
Author(s):  
Dima Alame ◽  
Maher Azzouz ◽  
Narayan Kar

Harmonic currents of electric vehicle (EV) chargers could jeopardize the power quality of distribution systems and add to the transformer’s losses, thus degrading its lifetime. This paper assesses and mitigates the impacts of different EV chargers on distribution transformers and the voltage quality of distribution systems. The effect of state-of-charge (SOC) of the EV battery is considered through applying weighted arithmetic mean to accurately assess the impacts of EV harmonic currents on aging and losses of the EV interfacing transformer. The voltage quality of the IEEE 33-bus distribution system, supplying several EV parking lots, is also assessed at different charging levels using a fast-decoupled harmonic power flow. A new optimal harmonic power flow algorithm—that incorporates photovoltaic-based distribution generation units (DGs)—is developed to enhance the voltage quality of distribution systems, and elongate the lifetime of the substation transformer. The effectiveness of the proposed mitigation method is confirmed using the IEEE 33-bus distribution system, hosting several EV charging stations and photovoltaic-based DGs.


2012 ◽  
Vol 61 (4) ◽  
pp. 483-497 ◽  
Author(s):  
Hessamoddin Jouybari-Moghaddam

Abstract A study on plug-in electric vehicle (PEV) charging load and its impacts on distribution transformers loss-of-life, is presented in this paper. The assessment is based on residential PEV battery charging. As the exact forecasting of the charging load is not possible, the method for predicting the electric vehicle (EV) charging load is stochastically formulated. With the help of the stochastic model, the effect of fixed, time of use, and real-time charging rates on the charging load and the resultant impact on transformer derating is investigated. A 38-bus test system is adopted as the test system including industrial harmonic sources. Test results demonstrate that uncontrolled EV charging might causes a noticeable change in the K-factor of the transformer, emerging the need for derating, while applying real-time rates for battery charging loads conquers this problem even in case of harmonic-rich chargers.


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