Energy and Power Engineering, 2013, 5, 1415-1420
doi:10.4236/epe.2013.54B268 Published Online July 2013 (http://www.scirp.org/journal/epe)
Communication Networking Schemes for Wide Area
Electric Vehicle Energy Service Network
Dequan Gao1,2, Jinping Cao3, Yiying Zhang1, 2 , Xiuli Wang4
1Beijing University of Posts and Telecommunications, Beijing 100876, China
2State Grid Information & Telecommunication Company Ltd., Beijing 100761, China
3China Electric Power Research Institute, Beijing 100192, China
4Information Communication Branch of Beijing Electric Power Company, Beijing 100031, China
Received March, 2013
ABSTRACT
Electric vehicles (EVs) are an emerging type of mobile intelligent power consumption devices in Smart Grid as new
green transport tools. In order to provide a powerful automation and intelligence support for wide area electric vehicles
energy service network, we analyze the network infrastructure and communications demands of various terminals,
devices and monitoring systems distributed in wide area electric vehicle energy service network. According to
interactive user services scenarios and en ergy operations intelligent monitoring, we propose multimode communication
integration architecture for wide area electric vehicle energy service network by means of the fusion of the Internet of
Things (IoT) technology. Then, we design different networking schemes in access networks and backbone transmission
networks meeting multi-scene and multi-operation interaction requirements. The networking schemes will provide
efficient technical support to implement intelligent, cross-regional, interactive energy services for electric vehicle users.
Keywords: Electric Vehicle; Wide-area Energy Service Network; Communication Networking; Internet of Things
1. Introduction
Many developed countries and megacities are undertak-
ing serious environmental pollution and great oil short-
age challenges. So world automobile industries are turn-
ing to develop clean energy vehicles with huge invest-
ment. Now, many people have realized that future trends
of automobile industry are green, energy-saving and in-
telligent. Electric vehicles (EVs) are seen as one of the
most promising means to improve the near-term sustain-
ability of the tran sportation and stationary energ y sectors
[1]. Electric vehicles have improved their performance
and made suitable for commercial and domestic use dur-
ing the last decades [2]. Electric vehicles will be promi-
nently taken as the mobile infrastructures of electrified
transportation mode. Electric vehicles development has
been as one of new energy national strategies in China.
More importantly, electric vehicle is an emerging type of
mobile intelligent power consumption device and energy
storage terminal for Smart Grid. With the large-scale
population of electric vehicles, electric vehicles can be
conventionally charged to play the role of the valley
filling in the power grid while its load is low. Thu s, they
will improve the comprehensive utilization efficiency of
power generation equipment, and achieve the effect of
energy saving and emission reduction. Inevitably, to
construct wide-area energy service network for electric
vehicles is the core premise of their large promotion.
According to the 12th Five-Year special plan on electric
vehicle technology development in China, a networked
power supply system, which includes 400,000 charging
piles and 2000 charging-swap stations, will be built in
above 20 demonstration cities and their surrounding
areas to meet the energy supply requirements of large-
scale commercial demonstration of electric vehicles until
about 2015.
The domain of electric vehicles opens new business per-
spectives and opportunities [3]. Electric vehicle energy
services businesses mainly cover battery charging, battery
swap, battery discharging, battery distribution, electric
energy metering and billing, fund settlement, scheduling
monitoring, etc. the basic operations functions are devices
running IntelliSense, real-time monitoring and warning
of battery status, vehicle status information acquisition,
charging-swap path intelligent navigation, battery life-
cycle management, centralized monitoring of equipment,
optimal allocation of resources, etc. The distributed smart
charging-swap information in energy service network
should be measured, interacted, shared and controlled,
which necessarily relies on rapid and reliable information
communication system.

D. Q. GAO ET AL.
1416
Next generation electric vehicles will radically change
the design paradigms in the automotive network domain
[4]. Ho wever, information communications network sup-
porting wide-area electric vehicle information acquisition
and key charging-swap service operations and monitoring,
has not met the practical, interactive requirements. These
problems have made intelligent interaction more difficult
between the power gr id and users, an d led to be unable to
provide conveniently, efficient and safe services for
electric vehicles users. Therefore, reliable information
communication technology (ICT) should be developed to
support information perception, aggregation, interaction,
and highly automated, in telligen t charging -swap services.
This paper focuses on the objectives of providing
efficient and interactive electric vehicles smart energy
services. Some exploratory researches involve wide-area
electric vehicles energy services network communica-
tions networking architecture. In this paper, we synthetically
apply the Internet of Things (IoT) technology and power
communication to improve intelligent perception of electric
vehicles energy information and services integration level
between electric vehicles and power grid.
2. EV Energy Service Network Facilities
Electric vehicle energy service network is indispensable
infrastructure for large-scale commercialization of elec-
tric vehicles. Many Chinese cities have released prefer-
ential policies and invested massive funds to promote the
construction of electric vehicle energy service facilities.
Generally, electric vehicle energy service network facili-
ties are composed of centralized charging stations, bat-
tery swap stations, battery distribution stations, AC
charging pile, operation monitoring center, etc. They will
guarantee reliable energy supply for electric vehicles in a
wide area.
Centralized charging stations can provide electric ve-
hicle battery charging and battery distribution stations.
Typically, a centralized charging station has the capabili-
ties of charging, discharging, maintenance and detection
of large amount of standardized battery packs.
Battery swap stations are power battery supply spots
by exchanging batteries for electric vehicle users. In a
battery swap station; there are power supply area, charg-
ing area, battery replacement area, battery inspection and
maintenance area, control room, parking lot, etc. Battery
distribution stations provide battery replacement and
logistics services for battery packs distribution without
charging function. AC charging piles are slow charging
devices for electric vehicles. The functions of a charging
pile involve timing, power energy measurement, costing
calculation. Operation service centers are responsible for
monitoring and management of regional electric vehicle
energy ser v i ce network o p erators.
3. Communication System Architecture of
Wide Area EV Energy Service Network
Shifting bulk l oads and dem a nd response programs require
communication between consumers and producers of
energy and will be more widely enabled with the expansion
of grid communication networks across the country [5].
The communication system of electric vehicle energy
service network will achieve the interconnection and
interoperability of all kinds of terminal, electric vehicle
and operations management system. The communication
system can support orderly, seamless cross-regional com-
munication services in the cities, provin ces, inter-city and
inter-provincial areas.
3.1. Communication System Demands
The characteristics of the communication system are
flexible networking, multi-mode access, and massive
access points. We analyze its demands from the view of
security, real-time and bandwidth. As an important part
of intelligent distribution and utilization networks, it is
linked with the power grid enterprise businesses such as
energy metering, tariff settlement, electricity manage-
ment. So po w er gr id mu s t be sa f e and s t ab le wh en a large
number of wide-area distributed charge-swap devices are
linked into it. Therefore, security requirements of wide-
area communication network are rather higher for opera-
tion service center.
All business surveillance, operations monitoring , video
monitoring, battery monitoring, power supply monitoring,
logistics distribution information of centralized charging
stations, battery-swap stations, battery distribution station,
and service management center must be real-time up-
loaded, so the real-time requirements of communication
performance are highly efficient. Moreover, electric ve-
hicles (including logistics vehicles) will upload vehicle
conditions, battery status information and receive value-
added services and scheduling information, relatively,
their real-time communication requirements are also
higher.
Electric power information acquisition system, opera-
tion management system, station-level monitoring sys-
tem need be deployed in centralized charging stations
and battery swap stations. Their communication band-
width is expected to reach MB level. The communication
bandwidth of charge piles and electric vehicles is
approximate 30 kbps.
3.2. Communication System Architecture
At present, there are some technical problems restricting
the large-scale commercial development of electric vehi-
cles in China. For example, the existing communication
networks cannot cover both urban and rural areas, cross
area to support complex electric vehicles services. Thus,

D. Q. GAO ET AL.
1417
we must integrate power communication network, the
public network (GPRS/3G/4G), cable network, wireless
sensor networks (WSN), and other communications
technology to establish top-level communication system
architecture of the electric vehicle energy services net-
work. The communication system will smart, effective
interaction between electric vehicles, battery packs,
charging-swap facilities and power grid, and seamless
mobile information services.
According to the above demand analysis of electric
vehicle energy network communication system, we
propose three-layer communication network architecture
supporting dynamic access and switch, as shown in
Figure 1. The network architecture will establish cross-
regional information transmission covering headquarters
operation service center, provincial operation service
centers, municipal operation service centers and station
monitoring center.
First-level network is the backbon e telecommunication
network linking operation service headquarters and sub-
ordinate operation service centers. First-level network
adopts power communication private network. However,
for the construction of power communication private
network relies on power transmission line path, it actually
hasn’t covered some expressways, provincial highways.
Power companies have built current communications
network involving optical fiber cable, microwave, Power
Line Carrier (PLC), satellite, which have fully covered
headquarters, provincial and municipal companies. There-
fore, the communication system of electric vehicle en-
ergy service network can further extend current enterprise
network to solve the wide-area coverage problem.
Second-level network is the transmission network
linking subordinate operation service centers and station
level facilities. Second-level network mainly adopts
provincial power communication private network. If the
private network isn’t available, the public communi-
cation network can be rented. Here, Access networks can
apply WSN, Optical Fiber Composite Low-voltage Cable
(OPLC), 3G/GPRS/4G/TD_LTE to implement infor-
mation exchange between charging-swap devices, vehicle
automatic identification equipment and monitoring equip-
ment, and information interaction between inner equip-
ment inside charging-swap stations, electric vehicles and
battery packs, and information access of geographically
distributed charging piles. On the whole, the communi-
cation network coverage is small for low-voltage side
distribution network. We can adopt wired communica-
tions (optical fiber communications, etc.), IoT com-
munication technologies and public wireless communi-
cations (GPRS/3G/4G) for different scenarios to ag-
gregate a variety of perception information, for example,
battery status information, identity information, electric
vehicle status information, location information, the
smart electric card identity information, charging-swap
environment information. The aggregated information
will be uploaded to the Second-level network layer
through the IoT aggregation gateway. Meanwhile,
charging-swap devices and various intelligent terminals
also receive control instructions.
Figure 1. Three-layer communication network architecture.

D. Q. GAO ET AL.
1418
4. Networking Schemes of Access Networks
Now the backbone telecommunication transmission net-
works and data communication network built by power
grid companies can basically meet communication business
demands of the First-level and Second-level network in
the energy service network architecture. Here, we will
mainly focus on designing networking schemes of access
network layer and take low-voltage power communica-
tion network as main basic of access network. We will
use self-built fiber network, electricity wireless broad-
band network, IoT technology together with renting public
network to solve heterogeneous interconnection and
collaborative communication problems for power wireless
broadband network, mobile communication network, and
WSN applied in different application scenarios. a particular
IoT service can be applied in order to optimize appli-
cation development and speed up application implementa-
tion [6]. Monitoring and automation applications will be
central for IoT and rely on eventing and group com-
munication [7]. These networking schemes will realize
seamless network coverage for centralized charging
stations, battery swap station , battery distribution stations,
charging pile and electric vehicles, and network access
within station sites.
4.1. Networking Scheme of Centralized Charging
Stations
The communication network within a centralized charging
station will connect with access network through the
access gateway nodes. The operations, power utilization
and monitoring information on the station LAN will be
transmitted to provincial service center, and share data
with electric vehicle operation management system. The
networking structure inside a centralized charging station
is shown in Figure 2. The following is networking
description.
1) Switches will be core nodes interconnection of
equipment inside centralized charging stations to suppo rt
station-level operations. A workstation connects core
switches via Ethernet interfaces.
Figure 2. Networking scheme inside centralized charging
station.
2) Charging devices access IoT communication gate-
way via industrial Ethernet or CAN bus, by which they
upload battery information and charger information to
the monitoring system, and also receive command in-
structions.
3) A power supply monitoring unit accesses IoT
communications gateway via RS232 interface. A collec-
tor uses RS485 interface to communicate with electric
energy meters and collect real-time consumption infor-
mation.
4) Video terminals send surveillance data to station
operation monitoring system via video cables.
5) Logistics vehicles can use micro-power wireless
network to automatically communicate with vehicle
identification readers inside a station.
In order to ensure station-level information network
security, local centralized charging station business
systems are logically isolated via Virtual LAN (VLAN)
technology.
4.2. Networking Scheme of Battery Swap
Stations
According to the practical communication requirements
in a battery swap station, the swap devices usually use
wireless communication technologies to link station- level
monitoring system, for example, WIFI, ZigBee. The
operations, power consumption and monitoring informa-
tion of a battery swap station will be sent to regional
operation management system via uplink network by
renting special public communication network.
In urban areas, a battery swap station will connect the
nearest 10kV switching substation, 35/110/220 kV
substation with fiber optic cable resources. While in
intercity highways or highway service areas, a battery
swap station will connect the nearest 35/110/220 kV
substation with fiber optic cable resources. The uplink
communications network fiber optic cable can be laid
along wit h power lines.
4.3. Networking Scheme of Charging Piles
Charging piles usually have CAN bus, PLC and RS485
communication interfaces, by which charging status
information can be sent to centralized monitoring system.
Charging piles can Real-time communicate with battery
management system (BMS) to get battery type, single
voltage, State-of-Charge (SOC), temperature and warning
information.
The uplink networks of charge piles have two access
ways: self-built power private networks and rented public
networks.
The operations information, power consumption infor-
mation and monitoring information can be uploaded via
LAN deployed in10kV distribution room, switching

D. Q. GAO ET AL. 1419
cabinet, box-type substation. Also, they can use embed-
ded wireless communication modules to connect public
network.
4.4. Networking Scheme between Charging-swap
Facilities and Operation Service Centers
The key communication requirements between charging-
swap facilities and the operation service centers of
energy network are wide communication range, rich data
semantic content and various bandwidth applications, so
we must flexibly use multiple communication tech-
nologies for different application scenarios. Power optical
fiber, PLC, GPRS and other communication technologies
can be mixedly used to communicate with operation
service centers fo r charging- swap stations an d distributed
charging piles. For power fiber cables only rely on
electric power communication systems resources, they
can avoid technical conflict on frequ ency resources, routing
coordination and electromagnetic compatibility with
other users. PLC technology is unique communication
way for power industry. The PLC scheme doesn’t need
to newly build communications infrastructure for it uses
power line as communication media for data transmis-
sion and information exchange. Station-level manage-
ment systems can real-time interact with electric vehicles
energy service management system in operation service
center, electric energy data acquire system and 95598
call center through power fiber-optic net work.
4.5. Networking Scheme of Electric Vehicles
The main external interaction objects of electric vehicle
are operation service centers, charging-swap stations and
charging devices. For mobility of electric vehicles, their
driving range, spatial location and speed are random.
Obviously, different communicatio n technologies will be
applied inside electric vehicles or while they are moving
in urban areas or on inter-city highways. The networking
schemes of electric vehicles are described in Figure 3.
Interactive services of electric vehicles in different
scenarios will adopt different communication modes.
Careful monitoring and control of energy flows allows
for minimum investment with respect to cost, weight and
Figure 3. Networking scheme of electric vehicles.
volume [8]. Users can get real-time battery status data
via vehicle CAN bus interface interacting with BMS
while driving. The application of bus technology with
CAN as the representative in vehicles not only reduces
the har-ness of the car but also in creases the reliability of
the car [9]. IoT based smart interactive terminals can be
embedded into electric vehicles to realize perception
information transmission among different interior parts.
Smart interac tive terminals integrate battery energy sensor,
temperature sensor, identification chip, communication
unit, GPS module, navigation software to realize battery
packs identification, power information collection, speech
warning and map navigation, etc.
Electric vehicles can use WIFI, micro-power wireless
network to interact with smart terminals via Iot gateways
set in charging-swap stations. Furthermore, they generally
interact with charging devices via CAN interface.
Users often adopt renting public wireless communi-
cation network to interact with service centers v ia GPRS/
3G/4G outside charging-swap stations. In the future, the
new generation power wireless broadband private network
and White Space (WS) technology-based low-frequency
wireless communication can be used to achieve region-
scale coverage data transmission. In general, wireless
mobile communication network can be used as the primary
networking means, the roadside big WiFi AP networks
and TD-LTE based new power wireless broadband com-
munications serve effective supplement means.
4.6. Communication Protocols and Interfaces
Security
The main communication interfaces of electric vehicles
energy service Network are data communication interface
of charging-swap devices, information interoperation
interface of operation monitoring center and BMS inter-
face of electric vehicles. In order to establish universal
communication protocol, we must find out the common
characteristics of electric vehicle charging demands and
charging-swap device functions from too many manu-
facturers. However, the communication protocol for
electric vehicles hasn’t been already unified for the BMS
interfaces from different manufacturers are special. To
actually ensure real-time data upload of monitor electrical
equipment operating condition, switch status and fault
alarm in charging-swap facilities, the modified IEC
60870-5 - 1 0 4 p ro tocol can be wi d el y used.
In order to ensure wired communications security
inside charging-swap stations, the monitoring systems of
charging-swap and power supply management must only
access the internal information network through com-
munication front-end processor. Station-level security
and protection subsystems ac cess upw ard s the n etwor k to
implement data transmission of video stream. Moreover,
the devices inside a station must firstly be requested to

D. Q. GAO ET AL.
1420
traverse firewalls for ensuring network security if they
will access to the internal information network. Under
some special conditions, public wireless networks may
be used in charging-swap stations if there are no wired
power network links. In the above case, the com-
munication front-end processor must be equipped with a
radio signal transceiver and a SIM card. Meanwhile, The
SIM card should have a static IP address. Thus, the
equipment in a station will access the internal infor-
mation network via public wireless communication
network according to the APN (Access Point Name)
special line of a station system
5. Conclusions
The reliable information collection, transmission, control
and management of electric vehicles and charging-swap
facilities are some important links to effectively super-
vise energy service proc edure. In order to adap t mobility,
diversity and universality requirements of electric vehicle
energy services, we make deep demand analysis on the
networking infrastructure and communications demands
of diverse terminals, devices and monitoring systems
distributed in wide area electric vehicle energy service
network. According to energy service scenarios for
electric vehicle and systematic requirements of intelli-
gent operation monitoring, we propose multimode com-
munication architecture for supporting wide area electric
vehicle energy service network with the fusion of IoT
technology. The architecture involves hybrid networking
mode widely covering expressways, national highways,
provincial highways, charging-swap facilities to imple-
ment seamless coverage and dynamic access of energy
service information. We integrate Multimode communi-
cation technologies to design interactive networking
schemes for EVs multi-business energy services. The
networking schemes will partly solve some basic
problems of perception data aggregation and information
communication support for cross-regional energy ser-
vices, and provide some technical means for friendly
information interaction.
Electric vehicle energy service infrastructures will
have rapid development in next decades in China. In fu-
ture, it is urgently necessary to innovatively use IoT
technology to build a demonstration platform of data
acquisition and information management for electric ve-
hicles energy service network. Moreover, the research on
information interaction methods between electric vehicle
and charging-swap networks should be further done.
Wireless smart sensors, perception tags, GPS and other
IntelliSense technologies need be integrated to fully
collect data in physical world for reliably solving the
problem of the electric vehicle performance assessment,
fault diagnosis, safety pre-warning and error risks
analysis.
6. Acknowledgements
This work is supported by National High-tech R&D
Program of China (863 Program) (No. 2011AA05A116,
2012AA050804) and National Program on Key Basic
Research Project of China (973 Program) (No.
2011CB302900).
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