Inter
national
J
our
nal
of
Electrical
and
Computer
Engineering
(IJECE)
V
ol.
7,
No.
6,
December
2017,
pp.
3147
–
3152
ISSN:
2088-8708
3147
I
ns
t
it
u
t
e
o
f
A
d
v
a
nce
d
Eng
ine
e
r
i
ng
a
nd
S
cie
nce
w
w
w
.
i
a
e
s
j
o
u
r
n
a
l
.
c
o
m
The
Effects
of
Nano
Fillers
on
Space
Char
ge
Distrib
ution
in
Cr
oss-Link
ed
P
oly
eth
ylene
A.
N.
Ramani
1
,
A.
M.
Ariffin
2
,
Gobinath
V
ijian
3
,
and
Ahmad
Basri
Abd
Ghani
4
1
F
aculty
of
Electrical
Engineering,
Uni
v
ersiti
T
eknikal
Malaysia
Melaka,
Malaysia
2,3
Department
of
Electrical
Po
wer
Engineering,
Colle
ge
of
Engineering,
Uni
v
ersiti
T
enag
a
Nasional,
Malaysia
4
TNB
Research
Sdn.
Bhd.,
Malaysia
Article
Inf
o
Article
history:
Recei
v
ed:
Jun
6,
2017
Re
vised:
Aug
21,
2017
Accepted:
Sep
3,
2017
K
eyw
ord:
Nanocomposites
Nanodielectrics
Polyeth
ylene
Space
char
ge
PEA
ABSTRA
CT
The
performance
of
polymeric
insulation
will
be
distorted
by
the
accumulation
of
space
char
ge.
This
will
lead
to
local
electric
field
enhancement
within
the
insulation
material
that
can
cause
de
gradation
and
electrical
breakdo
wn.
The
introduction
of
nanofillers
in
the
insulation
material
is
e
xpected
to
reduce
the
space
char
ge
ef
fect.
Ho
we
v
er
,
there
is
a
need
to
analyze
potential
nanofillers
to
determine
the
best
option.
Therefore,
the
objecti
v
e
of
this
research
w
ork
is
to
e
xamine
tw
o
types
of
nanofillers
for
Cross-Link
ed
Polyeth
ylene
(XLPE);
Zinc
Oxide
(ZnO)
a
nd
Acrylic
(P
A40).
The
ef
fects
of
these
nanofillers
were
measured
using
the
Pulsed-Electro
Acoustic
(PEA)
method.
The
de
v
elopment
of
space
char
ge
is
observ
ed
at
three
dif
ferent
DC
v
oltage
le
v
els
in
room
temperature.
The
results
sho
w
that
heter
o
char
ge
distrib
ution
is
domi
nant
in
pure
XLPE
materia
ls.
The
us
e
of
both
nanofiller
types
ha
v
e
significant
ef
fect
in
decreasing
the
space
char
ge
accumulati
on.
W
ith
nanofillers,
the
char
ge
profile
changed
to
homo-char
ge
distrib
ution,
suppressing
the
space
char
ge
formation.
Comparison
between
both
the
nanofillers
sho
w
that
P
A40
has
better
suppression
performance
than
ZnO.
Copyright
c
2017
Institute
of
Advanced
Engineering
and
Science
.
All
rights
r
eserved.
Corresponding
A
uthor:
Anis
Niza
Ramani
Uni
v
ersiti
T
eknikal
Malaysia
Melaka
Hang
T
uah
Jaya,
76100
Durian
T
ungg
al,
Melaka
Email
anisniza@utem.edu.my
1.
INTR
ODUCTION
Polymer
materials
are
widel
y
used
in
man
y
electrical
application
due
to
appropriate
processing
ability
and
e
xcellent
electrical
insulation
properties.
Examples
include
polyeth
ylene
(PE),
polyprop
ylene
(PP),
polyimide
(PI)
and
etc.
Ho
we
v
er
,
there
is
still
a
need
to
further
impro
v
e
the
insulation
properties
of
the
materials.
Therefore,
there
are
man
y
studies
that
focused
on
the
de
v
elopment
of
the
materials
using
the
concept
of
composite
in
order
to
im-
pro
v
e
material
properties
[1].
Recently
,
research
w
orks
ha
v
e
been
concentrating
on
the
application
of
nanomaterial
to
enhance
the
insulation
properties.
A
lot
of
w
ork
has
been
done
already
on
conduction
current
meas
urement
and
space
char
ge
observ
ation,
mostly
se
v
eral
decades
ago
re
g
arding
conduction
current
and
in
the
last
10
years
for
space
char
ge
[2].
The
presence
of
space
char
ge
modifies
t
he
electric
field,
increasing
the
inter
n
a
l
field
locally
within
the
dielectric
material,
which
leads
to
f
aster
de
gradation
and
premature
f
ailure
of
the
material
[3].
The
m
echanism
of
space
char
ge
formation
is
therefore
consi
dered
as
one
of
the
most
influential
f
actors
in
determining
the
o
v
erall
dielectric
properties
of
a
polymeric
insulation
system.
In
early
e
xperimental
w
ork
into
nanocomposite
in
connection
with
their
dielectric
properties,
reduced
space
char
ge
accumulation
w
as
reported
in
comparison
with
microcomposites
[4].
This
paper
will
e
v
aluate
the
ef
fects
between
of
tw
o
main
groups
which
are
metallic
oxides
(zinc
oxide)
and
rubber
(polyacrylate)
nanofillers.
J
ournal
Homepage:
http://iaesjournal.com/online/inde
x.php/IJECE
I
ns
t
it
u
t
e
o
f
A
d
v
a
nce
d
Eng
ine
e
r
i
ng
a
nd
S
cie
nce
w
w
w
.
i
a
e
s
j
o
u
r
n
a
l
.
c
o
m
,
DOI:
10.11591/ijece.v7i6.pp3147-3152
Evaluation Warning : The document was created with Spire.PDF for Python.
3148
ISSN:
2088-8708
2.
SAMPLES
PREP
ARA
TION
Three
type
of
samples
were
prepared
which
ar
e
dif
ferent
in
their
nano-sizes
and
content.
The
samples
are
unfilled
XLPE,
XLPE
with
a
fraction
of
1
wt%
nano-metallic
oxide
and
XLPE
with
a
fraction
of
1
wt%
nanorub-
ber
.
T
able
1
sho
ws
the
formation
of
samples.
Additi
v
e
free
XLPE
pellets
were
obtained
from
Borealis
and
the
material
name
is
Borlink
LE4201R.
There
are
2
types
of
nanoparticles
in
this
study
which
are
Zinc
Oxide
(ZnO)
nanoparticles
were
manuf
actured
by
US
Research
Nanomaterial
and
another
nanoparticle
is
Polyacrylate
(P
A40)
which
w
as
supplied
by
Kaneka.
These
nanoparticles
are
chosen
based
on
the
tw
o
main
groups
of
the
most
common
nanoparticles
used
for
electrical
insulating
nanocomposite
and
simple
chemical
structure.
After
the
mixing
process,
all
the
nanocomposite
materials
were
dried
i
n
an
o
v
en
at
55C
continuously
for
16
hours
r
especti
v
ely
before
the
e
xtrusion
process.
All
the
nanocomposite
materials
and
XLPE
pellets
were
compounded
using
an
e
xtruder
at
130C.
Then,
sample
films
were
prepared
by
hot-pressing
under
a
pressure
of
1000
psi
at
185C
with
an
a
v
erage
thickness
of
0.2
mm
and
a
diameter
of
70
mm
.
Film
samples
were
remo
v
ed
from
the
press
were
then
cooled
to
room
temperature.
T
able
1.
Sample
used
in
the
space
char
ge
measurement
Samples
Nanofiller
W
eight
Percentage,
wt%
XLPE
0
XLPE+ZnO
1
XLPE+P
A40
(Acrylic)
1
3.
EXPERIMENT
AL
W
ORKS
The
pulsed
electro-acoustic
(PEA)
technique
[5]
w
as
used
to
measure
the
space
char
ge
distrib
ution
for
the
v
arious
nanocomposites.
The
PEA
principle
is
schematically
represented
in
Fig.
1.
When
a
pulse
v
oltage
is
applied
to
the
sample,
it
will
produce
an
electric
field
impulse.
Char
ges
stored
in
the
sample
mo
v
e
under
the
ef
fect
of
the
Coulombs
force.
Acoustic
w
a
v
es
are
generated
and
propag
ated
in
the
sampl
e
and
then
detected
as
electric
signals
by
a
piezoelectric
sensor
attached
to
the
lo
wer
electrode.
The
amplitude
of
the
signal
is
proportional
to
the
char
ge
quantity
and
the
delay
indicates
the
position
of
the
char
ge,
taking
into
account
the
distance
from
the
sensor
.
A
piezoelectric
sensor
transforms
it
into
an
electric
signal
whose
amplitude
is
proportional
to
the
local
char
ge
density
.
These
signals
are
amplified
and
transferred
to
an
oscilloscope
[5].
Figure
1.
PEA
cell
scheme
Before
performing
the
measurements,
the
electrodes,
the
samples,
and
the
semiconductor
o
v
erlaying
the
sample
were
thoroughly
cleaned
using
isoprop
yl
alcohol.
In
this
study
,
a
pulsed
v
oltage
of
1.8
V
with
a
pulse
length
of
20
ns
w
as
applied
into
the
sample
for
a
fe
w
seconds
to
generate
an
acoustic
signal
w
a
v
e.
Then,
cali
b
r
ation
w
as
conducted
at
lo
w
DC
v
oltage
of
1
kVmm-1
with
short
enough
time
of
applic
ation
to
a
v
oid
space
char
ge
accumu-
lation.
The
de
v
elopment
of
space
char
ge
w
as
observ
ed
at
three
dif
ferent
DC
v
oltage
le
v
el
which
are
5,
10
and
15
IJECE
V
ol.
7,
No.
6,
December
2017:
3147
–
3152
Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE
ISSN:
2088-8708
3149
kVmm-1
that
lasts
for
30
minutes
at
room
temperature.
The
samples
tested
were
the
XLPE
with
nanoparticles
for
comparison
in
terms
of
space
char
ge
distrib
ution
while
the
pure
XLPE
material
is
used
as
reference.
The
dimen-
sion
of
sample
and
their
cross
section
is
illustrated
in
Fig.
2.
In
the
present
study
,
tw
o
dif
ferent
metallic
electrode
configurations
were
selected—brass
and
aluminium
(Al).
Figure
2.
The
dimension
of
sample
Then
the
sample
w
as
stressed
at
1
kHz
for
30
minutes
during
which
the
time
space
char
ge
w
as
measured
continuously
.
The
reproducibility
of
space
char
ge
w
as
v
alidated
by
repeating
the
e
xperiments
three
times
for
each
group.
4.
EXPERIMENT
RESUL
TS
The
space
char
ge
distrib
utions
were
measured
for
30
minutes
after
v
oltage
w
as
applied,
inducing
a
short
circuit
between
the
electrodes.
The
tw
o
electrode
positions
are
illustrated
by
the
v
erti
cal
dotted
lines
where
the
anode
is
located
on
the
right
while
the
cathode
is
on
the
left.
In
this
e
xperiment,
t
here
are
tw
o
measurement
results
which
were
used
to
in
v
estig
ate
the
electrical
properties
of
dif
ferent
nanofiller
materials—space
char
ge
accumulation
and
electric
field
distrib
ution.
4.1.
Accumulation
of
Space
Char
ge
As
sho
wn
in
Fig.
3,
after
dc
v
oltage
is
applied,
surf
ace
char
ge
is
induced
on
the
electrode.
When
the
v
oltage
is
more
than
5
kV
,
hetero-char
ges
which
are
the
space
char
ges
within
the
insulation
b
ulk
be
gin
to
de
v
elop.
Hetero-char
ge
distrib
ution
w
as
attrib
uted
by
the
cross-linking
reaction
and
magnitude
of
space
char
ge
that
rises
with
increasing
magnitude
of
applied
v
oltage.
At
15
kV
applied
v
oltage,
the
pack
ets
char
ges,
both
positi
v
e
and
ne
g
ati
v
e
char
ges
propag
ate
and
meet
in
the
middle.
This
leads
to
the
be
ginning
of
recombination
of
char
ge.
Figure
3.
Unfilled
XLPE
Figure
4
sho
ws
the
space
char
ge
distrib
ution
in
the
XLPE
with
1
wt%
nanofillers
after
the
v
oltage
is
applied.
Although
there
is
almost
no
ob
vious
space
char
ge,
sho
wn
in
Fig.
4a,
b
ut
a
v
ery
small
amount
of
homo-
char
ge
is
e
vident
near
the
cathode
such
that
space
char
ge
de
v
elopment
is
minimal.
It
can
be
seen
that
the
injected
The
Ef
fects
of
Nano
F
iller
s
on
Space
Char
g
e
(A.
N.
Ramani)
Evaluation Warning : The document was created with Spire.PDF for Python.
3150
ISSN:
2088-8708
(a)
ZLPE+ZnO
(b)
XLPE+P
A40
(Acrylic)
Figure
4.
Space
char
ge
accumulation
carriers
near
the
electrode
forms
a
small
amount
of
homo-char
ge
and
it
increases
with
the
duration
of
the
applied
v
oltage.
Char
ges
are
dictated
by
homo-char
ges
which
means
that
the
char
ge
injection
has
the
same
polarity
as
the
electrodes.
Figure
4b
sho
ws
a
small
amount
of
homo-char
ge
is
observ
ed
in
XLPE
with
1
wt%
P
A40
nanofillers.
As
sho
wn,
there
is
significant
dif
ferences
in
char
ge
profiles
between
XLPE
with
1wt%
ZnO
and
XLPE
wit
h
1%
P
A40
nanofillers.
The
magnitude
of
char
ges
in
P
A40
fillers
is
about
36.6%
less
than
that
in
ZnO
fillers.
From
the
char
ge
profiles,
it
is
clear
that
the
space
char
ge
density
increases
with
the
increasing
dc
v
oltage.
It
is
w
orth
to
note
that
the
de
v
elopment
of
homo-char
ge
is
commonly
associated
with
char
ge
inj
ection
processes
from
the
electrodes;
that
is,
positi
v
e
char
ge
injection
at
the
cathode
and
ne
g
ati
v
e
char
ge
injection
at
the
anode
[6].
This
trend
seems
to
be
consis
tent
with
the
published
results
from
[7],[8]
which
states
the
trend
of
the
increasing
magnitude
of
space
char
ge
indicates
the
possibility
of
the
presence
of
nano
filler
may
ha
v
e
delayed
the
char
ge
injection
or
resulted
in
more
homo-char
ges
being
generated
due
to
the
ionization
process.
4.2.
Electric
Field
Distrib
ution
Figure
5.
XLPE+ZnO
Figure
5
represents
the
electric
field
distrib
ution
of
XLPE
with
ZnO
nanofiller
sample
with
three
le
v
els
of
applied
v
oltage,
5,
10,
and
15
kV
.
In
the
be
ginning
of
v
oltage
application,
a
small
v
alue
of
electric
field
is
de
v
eloped
in
the
vicinity
of
the
electrodes.
Ho
we
v
er
,
when
10
kV
is
applied,
the
electric
field
be
gins
to
distort.
At
15
kV
,
electric
field
distortion
w
as
increased
to
99.35%
lar
ger
than
applied
v
oltage.
Figure
6
sho
ws
the
electric
field
inside
neat
the
samples
as
a
function
of
time.
As
it
is
well
kno
wn,
the
presence
of
space
char
ge
inside
insulating
materials
modifies
the
local
electric
field.
Through
PEA
measurements
the
electric
field
profiles
inside
the
insulator
can
also
be
obtained
along
the
thickness
of
the
sample.
IJECE
V
ol.
7,
No.
6,
December
2017:
3147
–
3152
Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE
ISSN:
2088-8708
3151
Figure
6.
XLPE+P
A40
(Acrylic)
In
general,
an
increase
in
the
applied
v
oltage
resulted
in
higher
a
v
erage
space
char
ge
for
most
of
the
nanocomposite
samples.
It
is
observ
ed
that
nanofillers
demonstrated
superior
char
ge
suppression
properties
[9].
The
nanofillers
introduced
or
increas
ed
the
deep
traps,
leading
to
the
decrease
of
char
ge
carrier
mobility
.
Additionally
,
nanofillers
could
also
modify
the
surf
ace
char
ge
transport
resulting
in
the
res
triction
of
space
char
ge
accumulation.
5.
CONCLUSION
It
w
as
observ
ed
that
an
increase
in
the
applied
v
oltage
resulted
in
an
increase
in
the
amount
of
accumulated
char
ge.
This
is
attrib
uted
to
enhanced
char
ge
injection
when
v
oltage
is
increased.
Hetero-char
ges
are
formed
for
XLPE
and
these
char
ges
can
be
reduced
by
the
addition
of
nanofillers.
Homo-char
ges
can
be
injected
into
nanocomposites
with
comparati
v
e
ease.
The
observ
ation
of
homo-char
ges
in
all
the
nanocomposites
m
ight
be
e
xplained
by
enhanced
char
ge
injection
due
to
the
addition
of
nanofillers
to
XLPE.
The
samples
reached
f
ast
char
ge
saturation
during
polarization
and
f
ast
depletion
of
char
ges
during
depolarization.
A
CKNO
WLEDGEMENT
The
main
author
w
ould
lik
e
to
e
xpress
her
appreciation
to
Uni
v
ersiti
T
eknikal
Malaysia
Melaka
(UT
eM)
and
Ministry
of
Education,
Malaysia
(MOE)
for
supporting
her
PhD
w
ork.
This
research
is
also
supported
by
the
cable
diagnostic
team
from
T
enag
a
Nasional
Berhad
(TNB)
Research.
REFERENCES
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akada,
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BIOGRAPHIES
OF
A
UTHORS
Anis
Niza
Ramani
recei
v
ed
her
B.
Eng.
from
Uni
v
ersiti
T
eknikal
Malaysia
Melaka
in
2006
and
Master
De
gree
from
Uni
v
ersiti
T
eknologi
Malaysia
in
2009.
She
is
currently
a
doctoral
student
in
the
Colle
ge
of
Engineering
at
Uni
v
ersiti
T
enag
a
Nasional.
Her
research
int
erests
lie
in
dielectric
materials,
high
v
oltage
engineering
and
space
char
ge
properties
of
insulating
materials.
Azrul
Mohd
Ariffin
is
Associate
Professor
in
the
Colle
ge
of
Engineering.
He
recei
v
ed
the
B.Eng.
de
gree
(2004)
in
electrical
engineering
and
the
Ph.D
de
gree
(2008)
in
electroluminescence
phe-
nomenon
in
insulating
polymers
from
the
Uni
v
ersity
of
Southampton,
UK.
He
is
no
w
a
Director
of
Programme
Management
Of
fice
(PMO)
at
Uni
v
ersiti
T
enag
a
Nasional.
His
researches
are
in
fields
of
high
v
oltage
engineering
and
electroluminescence
phenomenon
in
insulati
ng
polymers.
He
is
af
filiated
with
IEEE
and
Board
of
Engineers,
Malaysia
(BEM)
as
a
member
.
Gobinath
V
ijian
is
recei
v
ed
B.Eng
(Hons)
de
gree
in
Electrical
Po
wer
Engineering
from
Uni
v
ersity
of
T
enag
a
Nasional
in
2016.
No
w
he
is
currently
pursuing
post
graduate
studies
in
the
same
uni-
v
ersity
.
His
current
research
interest
include
ne
w
insulation
material
to
replace
xlpe
in
under
ground
cable
that
are
widely
used
in
Malaysias
lar
gest
electricity
pro
vider
,
the
TNB.
Ahmad
Basri
Abd
.
Ghani
is
recei
v
ed
his
B.Eng
(Hons)
in
Electrical
Engineering
de
gree
from
Uni-
v
ersity
of
Southampton,
UK
in
1992.
In
2002,
he
recei
v
ed
his
M.Eng
in
Engineering
Management
de
gree
from
Uni
v
ersity
T
enag
a
Nasional,
Malaysia,
and
in
2008
he
recei
v
ed
his
PhD
in
Engineer
-
ing
de
gree
from
Uni
v
ersity
T
enag
a
Nasional,
Malaysia.
In
1992,
he
joined
T
enag
a
Nasional
Berhad
(TNB)
as
Operation
&
Maintenance
Engineer
,
and
in
year
2000,
he
joined
TNB
Research
as
the
Principal
Researcher
.
He
is
a
re
gistered
Professional
Engineer
with
Board
of
Engineer
Malaysia
since
1995.
Since
2014,
he
has
been
a
Seni
or
Manager
in
TNB
Research.
His
current
research
in-
terests
include
under
ground
cable,
partial
dischar
ges,
nanodielectrics,
cable
ampacity
calculations,
space
char
ge
&
high
v
oltage
technology
.
IJECE
V
ol.
7,
No.
6,
December
2017:
3147
–
3152
Evaluation Warning : The document was created with Spire.PDF for Python.