TELKOM
NIKA
, Vol. 11, No. 4, April 2013, pp. 2247
~22
5
2
ISSN: 2302-4
046
2247
Re
cei
v
ed
De
cem
ber 8, 20
12; Re
vised
Ma
rch 1, 201
3; Acce
pted
March 9, 201
3
The Electric Vehicle Lit
h
ium Battery Monitoring System
Lei Lin
1
, Yua
n
kai Liu*
2
, Wang Ping
3
, Fang Hon
g
4
1
School of Ele
c
tric and Infor
m
ation En
gi
ne
erin
g
of Che
n
g
du Un
iversit
y
, Che
ngd
u 61
01
06, Chi
n
a
2
School of Aut
o
matio
n
Eng
i
n
eeri
ng of Univ
e
r
sit
y
of
Electro
n
ic Scie
nce a
n
d
T
e
chnolo
g
y
of Chin
a, Che
n
gdu
611
73
1, Chin
a
*Corres
p
o
ndi
n
g
author, e-ma
i
l
: liu
yu
anka
i
0
3
03@
126.com
A
b
st
r
a
ct
W
i
th the
glo
bal
incre
a
se
in
th
e n
u
m
ber
of v
ehi
cl
es, e
n
viro
nmenta
l
pr
otec
tion
and
e
nerg
y
issu
e
s
had bec
ome
i
n
creasi
ngly pro
m
i
n
e
n
t.
Peop
le
pai
d more an
d
more
attenti
on to the
el
ectric vehic
l
e
as th
e
future d
i
rectio
n
of the
ve
hicl
e, but
beca
u
se
the
batte
ry tec
h
nol
ogy w
a
s r
e
l
a
tively
backw
a
r
d, it h
ad
bec
o
m
e
the bottle
neck
in the d
e
vel
o
pment of
el
ectric vehic
l
es. S
o
in the
ex
isti
ng con
d
iti
ons,
a perfect batt
e
ry
Monitori
ng tec
hno
logy
ha
d
beco
m
e more
and
mor
e
i
m
p
o
rtant. T
h
i
s
pap
er firstly analy
z
e
d
t
h
e
character
i
stics
of lithi
u
m
batte
ry resid
ual c
a
p
a
city an
d
effec
t
factors, then
put forw
ard to
a set of sol
u
tio
n
s
according to the actual sit
uation. The solution of th
e
lithium battery M
o
nitoring
system
adopted distribut
ed
structure, incl
udi
ng d
e
tectio
n of
volta
ge,
current, temperatur
e an
d
me
asur
e
m
ent
mo
dul
e a
n
d
the
reali
z
a
t
io
n of mono
mer
b
a
ttery
eq
ual
i
z
e
r
mod
u
le. Usin
g a
si
ngl
e
b
u
s dev
ic
e
DS
24
38 pro
d
u
ced
by
DAL
L
AS
on the battery
voltage, current, tem
per
ature,
power and ot
her paramete
r
s
, the system
controlled DS2438
by the ST
C8
9C5
2
sing
le-c
hip i
n
data a
c
quisiti
on.
T
h
en it used th
e alg
o
rith
m to pred
ict state of
charg
e
(SOC) and d
i
spl
a
ye
d
the battery status in the
L
CD16
02. T
h
is
solutio
n
of the lithi
u
m
bat
tery
Monitori
ng syst
em w
a
s reli
abl
e, econo
my, strong a
n
ti-int
erferenc
e abi
lity.
Ke
y
w
ords
: ele
c
tric vehicl
e, lithiu
m
b
a
ttery, battery mo
nitor, SOC, equil
i
brat
ion
Copy
right
©
2013 Un
ive
r
sita
s Ah
mad
Dah
l
an
. All rig
h
t
s r
ese
rved
.
1. Introduc
tion
In con
s
ide
r
ati
on of larg
e current of lithium
battery in
quick ch
arge
, rapid di
scha
rge [1],
vibration, extrusio
n an
d oth
e
r he
avy con
d
itions, it
ma
y cau
s
e a fi
re
, explosio
n safety acci
den
t. It
is difficult to
meet the
req
u
irem
ents of
"low
co
st, hi
gh volum
e
a
nd hig
h
se
cu
rity". For the
s
e
probl
em
s, this pa
per
d
e
votes p
o
wer ele
c
tr
oni
c techn
o
logy,
singl
e-chip
microcomp
u
ter
techn
o
logy, intelligent control, opti
m
al algorith
m
and ele
c
tro
c
he
mical
scie
n
ce to the
developm
ent of high intelli
gent ele
c
tri
c
vehicle lit
hiu
m
battery en
ergy monito
ri
ng syste
m
[2], it
can u
s
e
battery ene
rgy m
o
re effici
ently in compl
e
x environ
ment.
It not only can do e
n
sure
the
safe and
reli
able ope
ratio
n
, but can gi
ve full play to the life of the battery a
nd cha
r
gi
ng and
discharging ability. So the resear
ch
of battery monitori
ng
system
has pl
ayed m
o
re
and more key
role in th
e gene
rali
zatio
n
of the el
ectri
c
vehi
cl
e market a
nd improve
m
ents of ve
hicle
performanc
e
[3].
2. Design of
the Electric Vehi
cle Ba
tter
y
Monitoring Sy
stem
Electri
c
vehicl
e battery mon
i
toring sy
ste
m
inc
l
udes
the following s
e
veral parts
[4-6].
2.1. Data
Col
l
ection
Colle
ction
of
each b
a
ttery
cha
r
a
c
teri
stic param
ete
r
s:
terminal
volta
ge, battery'
s
surfa
c
e
temperature,
cha
r
ge a
nd di
scharge curre
n
t and total voltage.
2.2. Electrica
l Control
Cha
r
ge a
nd d
i
scharge cont
rol, balan
ce
charg
e
and di
scha
rge te
chn
o
logy.
2.3. Data
Co
mmunicatio
n
The examin
ation of lithium battery
dynamic param
eters and displ
a
y, data
comm
uni
cati
on
with oth
e
r
mo
dule
s
, e
s
tabli
s
h
co
m
m
unication
s
bus for exch
angin
g
d
a
ta
with
displ
a
y system, the vehicle c
ontroller and chargers to fa
cilitate centralized cont
rol.
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ISSN: 23
02-4
046
TELKOM
NIKA
Vol. 11, No. 4, April 2013 : 2247 – 2
252
2248
2.4. Heat M
o
nitoring Abil
it
y
Advanced heat monitoring ability can
main
tain t
h
e balance of
temperature
between
battery modul
es, and
control cell temp
e
r
ature in the reasona
ble scope.
2.5. Displa
y
and Re
cordi
ng Part
After getting i
n
the ri
ght ba
ttery state, proc
e
edin
g
he
a
t
monitorin
g
,
battery eq
uali
z
ation
monitori
ng, charg
e
and di
scha
rge m
onit
o
ring, fault al
arm, and
sho
w
battery pa
rameters.
Figure 1. Electri
c
Vehicl
e Lithium Battery Monitorin
g
System
3. The Prediction of
Resi
dual Cap
acity
Batter
y
SOC
In order to
cha
r
a
c
teri
ze
resi
dual
cap
a
city of the
ele
c
tri
c
veh
i
cle
batterie
s
mo
re
accurately an
d scie
ntificall
y
, usually u
s
e the
ba
ttery
ch
arg
e
state
ch
ara
c
te
rization, nam
ely the
SOC (State
Of Cha
r
g
e
) [
7
], it is impo
rtant pa
rame
te
rs i
n
the p
r
o
c
ess of batte
ry use. At p
r
e
s
ent,
the dom
esti
c and i
n
ternat
ional m
o
re
widely u
s
e b
a
ttery state
of ch
arg
e
SO
C to
refle
c
t the
resi
dual
capa
city, and it
s
n
u
meri
cal
valu
e is defin
ed
a
s
the
rest
of the b
a
ttery p
o
w
er for batte
ry
c
a
pac
i
ty ratio
SOC=
Qc
/Co
(1)
On the type, f
o
r the
re
st of
the battery Q
c
u
s
abl
e en
ergy, Co for no
minal
capa
cit
y
of the
battery, in a
specifie
d curre
n
t and temp
e
r
ature in
the i
deal
con
d
ition ca
n rel
e
a
s
e
energy. Usu
a
lly
the certai
n te
mperature
s
state of b
a
ttery can
'
t
ab
so
rb en
ergy is d
e
fined
100%,
and
the
stat
e of
battery can
'
t relea
s
e en
erg
y
is defined el
ectri
c
ity state 0%.
Figure 2. Lithium Battery SOC Es
timation
For th
e lithiu
m
battery, th
e re
sid
ual
capa
city is inf
l
uen
ced
by
many facto
r
s [8]: the
discha
rge
cu
rrent, the temperatu
r
e of th
e battery
,
t
he self
-di
s
cha
r
g
e
rat
e
,
cy
cl
e t
i
mes,
et
c.
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
The Elect
r
ic
Vehicle Lithi
u
m
Battery Mo
nitoring S
yste
m
(Lei Lin)
2249
On the
b
a
si
s of
the
ana
lysis
of the
factor
s affecti
ng the
lithiu
m
battery
re
mainin
g
cap
a
city, syn
t
hesi
z
ing the
advant
age
s and disadvan
tages of existi
ng predi
ctio
n method
s, this
pape
r
p
u
ts
fo
rwa
r
d a com
posite re
sid
u
a
l
ca
pa
ci
ty p
r
edi
ction m
e
thod:
combi
n
ed with
amp
e
re
-
hour metho
d
, open
voltag
e metho
d
an
d the
kalma
n
f
ilter metho
d
to fore
ca
st the a
c
tual
bat
tery
cap
a
city, to
accurately predict re
sid
ual
capa
ci
ty of the battery. First of all, use open volta
ge
method to m
easure i
n
itial
capa
city, an
d then
u
s
e a
m
pere-h
o
u
r
method a
nd
the kalm
an fi
lter
approa
ch met
hod [9] to ca
culate the dyn
a
mic re
si
dual
capa
city battery, and com
pare th
e re
su
lts
of the two m
e
thod
s to
ch
eck the
a
c
tu
al battery
ca
pacity to
ach
i
eve the p
u
rp
ose
of a
c
curate
predi
ction.
4. Batter
y
Pa
ramete
rs Me
asureme
nt
Single cell m
easure
m
ent
s of circuit diag
ram is
sho
w
n
as Figu
re 4.
Figure 3. Battery Param
e
te
r Dete
ction Ci
rcuit
Figure 4. DS2438 Me
asurem
ent Ci
rcuit Diagram
For the de
sig
n
of single lithium battery seri
es g
r
ou
p, the system use
s
a dete
c
ting ch
i
p
DS243
8 [10]
whi
c
h
can
suppo
rt multip
le batte
rie
s
cascad
e control and
com
m
unicate with
o
u
t
comm
on e
a
rt
h und
er
high
voltage. The
sha
pe of
b
a
ttery group
ca
n
be de
sig
n
fle
x
ibly and pla
c
ed
distrib
u
tedly, whi
c
h meet
s the require
ments of
large cap
a
city, high po
we
r according to
th
e
different appl
ication
s
. Each battery is config
ure
d
a
data acqui
si
tion boards t
o
gather eve
r
y
singl
e battery
param
eters,
lithium battery sup
p
ly po
wer fo
r DS2
438 at the
same time. If the
GN
D
1
Vs
e
n
s
+
2
Vs
e
n
s
-
3
Va
d
4
DQ
8
NC
7
NC
6
VD
D
5
D
S
24
38
D3
D
S
24
38
R6
5K
R5
100K
1
2
CH
c
h
a
r
g
e
1
2
DS
1
2
3
DA
DA
T
A
HE
AD
E
+C
3
10
4
R4
20m
Ω
VI
N
+
GN
D1
B1
M
eas
u
r
ed
b
a
t
t
ery
VD
1
+
GN
D1
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ISSN: 23
02-4
046
TELKOM
NIKA
Vol. 11, No. 4, April 2013 : 2247 – 2
252
2250
battery mea
s
ured
is m
ade
up of
severa
l monom
er
serie
s
an
d
sh
are
a DS2
4
3
8
, voltage wil
l
be
more
than
DS2438
wo
rkin
g voltage,
we
ca
n u
s
e
p
r
ec
ise
re
sista
n
ce
to divide, th
e
n
lo
wer volta
ge
sup
p
ly chip
s
work. Mea
s
u
r
ing prin
cipl
e diagram is
sh
own a
s
Figu
re 3.
5. The Balan
ce of Batter
y
Bod
y
Based
on the synthesis
of t
he advantages and di
sadvantages of
the existing equilibri
um
methods, adopting the
switch
of
capacitance e
quilibri
um method t
h
rough
the program to
control
cell in th
e stat
ionary
state, throu
gh the
switch
to
balan
ce different m
onome
r
s inde
pend
ently, an
d
sho
r
tenin
g
th
e di
scharge l
e
vels. T
h
is schem
e i
s
si
m
p
le a
nd
relia
b
l
e, its bi
gge
st
advanta
ge i
s
to
balan
ce the
unit cell in the cha
r
ge a
n
d
discharge
proce
s
s, and n
o
t to consum
e lithium battery
energy. Disa
dvantage i
s
capa
citan
c
e di
scharge only
in the adja
c
e
n
t batterie
s
, so it need to p
a
y
attention to control the capacitance
charging
time to prevent capaci
tor filling explosion.
Figure 5. Switched Ca
pacitor Equilibrium
6. The Soft
w
a
re Re
aliza
t
ion of Electri
c Ve
hicle Lithium Batter
y
Monitoring
Sy
stem
The
softwa
r
e
is
reali
z
e
d
b
y
the co
rresp
ondin
g
ha
rd
ware
ci
rcuit, by using
a
sin
g
le bu
s
device
DS24
38, whi
c
h sa
mples m
a
in p
a
ram
e
ters su
ch a
s
battery
voltage, cu
rre
nt, temperatu
r
e,
and p
o
wer.
The dat
a is
pro
c
e
s
sed b
y
the si
ngl
e-chip mi
cro
c
o
m
puter ST
C89C52. The
n
the
p
r
oc
es
se
d
data
is
c
o
mb
in
ed
w
i
th
th
e
pr
es
e
n
t
va
l
ue, a
nd the battery
normal
state
is displayed o
n
the LCD1602. The sy
sytem will al
ar
m
when there i
s
a fault .The
ma
in program process chart is
s
h
ow
n
as
fo
llo
w
.
Figure 6. Flow Ch
art of Main Prog
ram
7. The Simulation Results and An
aly
s
is
In ord
e
r to v
a
lidate th
e a
c
tual
effect
of
the
com
posite
re
sid
u
a
l capa
city p
r
edi
ction
method, co
n
duct the ch
argin
g
and
dischargi
ng
test at room tempera
t
ure, and u
s
e
MATLAB/SIMULINK s
o
ftware
to s
i
mulate
battery
SOC e
s
timated
algorith
m
mo
deling [10]. T
he
results a
r
e sh
own a
s
Figu
re 7 and Figu
re 8.
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
The Elect
r
ic
Vehicle Lithi
u
m
Batt
ery Mo
nitoring S
yste
m
(Lei Lin)
2251
Figure 7. MATLAB Simulation Plans
Acco
rdi
ng
to
the simul
a
tion
results,
in the later disch
a
rg
e
,
becau
s
e
of erro
r
accumul
a
tion
, the preci
s
io
n of kalman fi
ltering meth
o
d
is high
er th
an ampe
re
-h
our meth
od'
s.
In the sysytem, Ampere
-
h
our meth
od calc
ul
ation formula is sho
w
n as follo
w:
SOC=
SOC
0
-
0
t
I(t)dt
(2)
Discrete syst
em kalm
an filter formula
s
a
r
e as follo
w:
X(k+
1)=
A
(k)X
(k)+
B
(
k)U(k
)
+W(k
)
(3)
Y(k)=C(k
)X
(k
)+
V(k
)
(4)
X(
k
|
k-
1)
=
A
(
k
-1)
X
(k
-1)+
B(k
-
1)
U(k
-
1)
(5)
X(k)=
X
(k
|
k
-1)+
K(k
)
[Y(k
)-Y(k
)
]
(6)
P(
k
|
k-
1)
=
A(k-
1)
P
(
k-
1)
A
T
(7)
K(k)=
P(k
|
k-1)C
T
(k)
[
C
(
k)
P(k
|
k-
1)
C
T
(k
)+R
]
-1
(8)
P(
k)
=
[I-
K(k)
C(
k)
]P(
k
|
k
-1)
(9)
In the above
formula, X(k) is
state ve
ctor, U(
k) is
control ve
ctor,
Y(k) is
ob
se
rvation
vector, W(k) and
V
(
k)
i
s
n
o
ise
vecto
r
,
A(k), B(k) an
d C(k) ar
e coefficient mat
r
ix,
P(k|
k-1)
and P(k) a
r
e
state variabl
e
s
pre
d
icte
d e
rro
r and t
he
error of filter varian
ce a
rra
y, Q and R
r
e
spec
tively is
the var
i
ance
array of noise W(k) an
d V(k).
Figure 8. SOC Simulation
Curve
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ISSN: 23
02-4
046
TELKOM
NIKA
Vol. 11, No. 4, April 2013 : 2247 – 2
252
2252
8. Conclusio
n
The pa
pe
r of
fers
a solutio
n
of lithium b
a
ttery monito
ring
system
based o
n
Sin
g
le Chip
Microcomput
er(S
CM) and
DS243
8,
this sy
stem can
more
accu
ra
tely measu
r
e
battery voltage,
curre
n
t and tempe
r
ature d
a
ta. After the
system te
st, SOC arithm
etic is relia
bl
e, the judge of
battery state
is accu
rate, sendin
g
the ba
ttery
state me
ssage to the
centra
l proce
ssi
ng sy
stem
is
fast, the anti-i
nterference
ability is
strong and di
splaying through the
liquid crystal
is real
-time. At
the sa
me, th
e equili
bratio
n functio
n
sol
v
es un
bala
n
ced voltage
of the mon
o
me
r battery
ca
u
s
ed
by the overch
arge. Thi
s
sol
u
tion re
ache
s the
expecte
d
desig
n re
quirements
and p
r
ovide
s
a ne
w
referen
c
e for
the further
study of electri
c
v
ehicl
e lithium battery m
onitorin
g
syst
em.
Akno
w
l
e
dge
ment
This project
i
s
sup
porte
d by
scien
c
e a
nd
te
chnol
og
y sup
port
pla
n
of Sichua
n
provin
ce
(201
1GZ
019
4), Chin
a.
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ces
[1]
W
u
T
i
ezhou, Cao
Quan, Li
u
Lu
nan,
Xia
o
Qing,
W
a
n
g
Xi
e
y
an
g. Res
ear
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n
the
fast
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gin
g
of
VRLA.
T
E
LKOMNIKA Indone
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unzho
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w
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gn
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a
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e
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g
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cro
c
om
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te
r
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ng-s
hun
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i
u
m Batter
y
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otection
Circ
u
i
t
Desig
n
for
E
l
ectric Ve
hic
l
e
Base
d o
n
AT
mega16L Si
ngl
e-chi
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e
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ng s
y
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e
h
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cle
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w
e
r
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.
Ch
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e
s
e
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a
l of Pow
e
r Sources.
20
11; 25: 35-
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hao
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an.
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h
e
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h
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timate
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d
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ual c
a
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lia
n
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i
t
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e
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g
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ng W
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u
a
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y
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g
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[9]
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u
Hong
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w
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pre
d
i
c
tion al
gorithm
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y
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ic Mea
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e
n
t and I
n
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[10]
T
i
ezhou W
u
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una
n Li
u, Qing
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ao, Qu
an C
ao,
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y
a
n
g
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ang. R
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on sec
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n
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-ord
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d
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E
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nesi
an
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a
l
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c
trical En
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e
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