Developing PHEV Charging Load Profile Based on Transportation Data Analyses

Developing PHEV Charging Load Profile (PCLP)

• PHEV: Plug in Hybrid Electric Vehicle

• PCLP: PHEV Charging Load Profile The amount of electricity demanded for charging PHEVs in a specification region at any given time.

Student(s): Zahra Darabi, Electrical and Computer Engineering

Background• Three key questions :

i. when each vehicle begins to be charged,

ii. how much energy is required to charge it,

iii. what level of charge is available.

• In Previous studies:

• Total load profiles with and without PHEVs were compared

• Main objective has not been the building of a PCLP

• There was no detailed information about the data on which those profiles are based

• A load demand schedule of PHEVs was provided but the time of day at which vehicles are charged is not indicated.

• The most comprehensive reference for transportation data is the National Household Travel Survey (NHTS)

Base of PCLP- Daily Mileage

• The most common mileage is in the range of 25-30 miles.

55% of vehicles are driven 30 30 miles daily or less

• Utility Factor (UF) is the fraction of total miles driven by electricity.

• Electric Range Utility Factor (ERUF) is the ratio of miles driven by electricity to the potential number of miles displaced by electricity.

• The intersection of two curves occurs at 30 miles.

Faculty Advisor(s): Dr. Mehdi Ferdowsi, Electrical and Computer Engineering

Base of PCLP- Daily Mileage

• State Of Charge (SOC) is the percentage of charge remaining in the vehicle when it arrives. The SOC of a vehicle can be determined based on miles driven and the electric range (x) of the PHEV.

Base of PCLP- Arrival Time

• The peak arrival time is between hours 16 and 22.

Developing PCLPs

• Total power (t)= Power required by vehicles arriving at (t) + Power required by vehicles that have arrived since (t-n)

• Battery Utility Factor (BUF) is the fraction of total electricity consumed.

• Two approaches produces almost identical PCLPs

• Most of the time the PCLP of PHEV40s overlies those of PHEV30s and PHEV20s

• 11:00 to 17:00 PCLPs are almost the same

• Peak time of PCLPs is 18:00 to 23:00

• The PCLP of PHEV30s is closer to that of PHEV40s

• Larger PHEV results better UF and peak time, but worse ERUF, BUF, and peak load

Base of PCLP- Vehicles Type

• The first four types of vehicles are selected for this study

Type 1 is the most common is vehicle type. are

• The four PHEV types are mapped to the four types of the 2001 NHTS data

• The energy required of four types of PHEV20

• The average kWh/mile is 0.37 (based on the number and kWh/mile of each vehicle types).

Improving Policies based on PHEV30• PCLPs of various charging levels

(for PHEV30)

• As the charging level increases: ∙ the peak point moves to the left ∙ the peak value rises

• Policy 1: Vehicles, arriving between 0:00 and 16:00, get charging level of 7.68 kW and the rest get that of 1.4 kW

• Policy 2: Vehicles, arriving after 16, are charged 2 hours later

Charging Levels & Charging Schedule

• Three charging levels based on two references

• Fully charging schedule (based on the charging level 1)

Two approaches to scale charging schedule based on SOC

• Power scaling approach scales the electric power delivered to each vehicle at each hour. (constant time )

• Time scaling approach considers maximum power available at each time and scales the total energy required. (constant power)

FUTURE WORK

• Developing smart charging profile

• Defining attributes for PCLPs

• Quantitative assessments of PCLPs

• Determining probability distributions for the three sides of the PCLP prism based on NHTS data

• Developing probabilistic PCLPs

• This work has been partially supported by the Intelligent Systems Center at the Missouri University of Science and Technology

Acknowledgements

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Time of day

Vehicle Type 1 2 3 4 Number 23,881 4,686 5,139 5,536

Percentage 60.85% 11.94% 13.1% 14.11%

Type Total kWh kWh/mile Compact Sedan 6.51 0.3255 Mid-size Sedan 7.21 0.3605 Mid-size SUV 8.75 0.4375 Full-size SUV 10.15 0.5075

Types of vehicles in NHTS 01 Automobile/car/station wagon 02 Van (mini, cargo, passenger) 03 Sports utility vehicle 04 Pickup truck 05 Other truck 06 RV (recreational vehicle) 07 Motorcycle 91 Other

Level Reference

1 2 3

EPRI- NEC 120VAC, 15A (12A) 1.44 kW

240VAC, 1phase, 40A 480VAC, 3phase, 60 to 150 kW

SAEJ1772 120VAC, 12A, 1phase 1.44 kW

208-240VAC, 1phase 32A, 6.66-7.68kW

208-600VAC, 3phase, 400A, >7.68 kW

Hour Type

1 2 3 4 5 6 7 8 Total kWh

01 1.4 1.4 1.4 1.4 0.91 0 0 0 6.51 02 1.4 1.4 1.4 1.4 1.4 0.21 0 0 7.21 03 1.4 1.4 1.4 1.4 1.4 1.4 0.35 0 8.75 04 1.4 1.4 1.4 1.4 1.4 1.4 1.4 0.35 10.15

PHEV20 PHEV30 PHEV40 Miles driven by electricity 671,888 903,423 104,409 UF 0.522 0.703 0.812 ERUF 0.856 0.767 0.665 Consumed total electrical energy (𝑬 kWh)

249,469.8518 336,026.5069 389,086.33675

BUF 0.859 0.771 0.669 Peak load (kW) 25000 30000 32000 Peak time 20:30 21:45 22:00

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