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4430
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r
o
r
s
in
tr
a
n
s
m
is
s
i
o
n
co
n
t
r
o
l sy
s
tem
s
.
T
o
en
h
an
ce
th
e
p
o
wer
q
u
alit
y
(
PQ)
p
ar
am
eter
s
o
f
r
ailway
elec
tr
if
icatio
n
s
y
s
tem
,
r
esear
ch
er
s
h
av
e
ex
p
lo
r
ed
v
a
r
io
u
s
m
et
h
o
d
s
o
v
er
th
e
y
ea
r
s
.
A
d
d
r
ess
in
g
NS
C
h
as
b
ee
n
a
f
o
ca
l
p
o
in
t,
with
s
o
lu
tio
n
s
s
u
c
h
as
s
p
ec
ially
d
esig
n
ed
tr
an
s
f
o
r
m
e
r
s
,
in
clu
d
in
g
Sco
tt,
W
o
o
d
b
r
i
d
g
e,
im
p
ed
a
n
ce
-
m
atch
i
n
g
b
al
an
ce
,
an
d
L
eBl
an
c
tr
an
s
f
o
r
m
er
s
[
1
8
]
–
[
2
3
]
.
R
ea
c
tiv
e
p
o
wer
co
m
p
en
s
atio
n
h
a
s
b
ee
n
an
o
th
er
ar
ea
o
f
f
o
cu
s
,
with
s
ta
tic
VA
R
c
o
m
p
en
s
ato
r
s
(
SVC
)
[
2
4
]
–
[
2
6
]
an
d
s
tatic
s
y
n
ch
r
o
n
o
u
s
co
m
p
en
s
ato
r
s
(
STAT
C
OM
)
[
2
7
]
,
[
2
8
]
wid
ely
u
tili
ze
d
.
W
h
ile
SVC
s
d
y
n
am
ically
co
m
p
en
s
ate
r
ea
ctiv
e
p
o
wer
,
t
h
ey
g
e
n
er
ate
h
ar
m
o
n
ics,
wh
ic
h
STAT
C
OM
s
ca
n
m
itig
ate.
Sin
g
le
-
p
h
ase
STAT
C
OM
s
ar
e
well
-
s
u
ited
f
o
r
r
ailway
f
ee
d
er
s
with
lo
w
is
o
latio
n
n
ee
d
s
,
wh
ile
th
r
ee
-
p
h
ase
STAT
C
OM
s
ca
n
d
y
n
am
ically
ad
d
r
ess
NSC
b
u
t r
eq
u
i
r
e
lar
g
e
s
tep
-
d
o
wn
tr
an
s
f
o
r
m
e
r
s
.
Ad
d
itio
n
al
m
eth
o
d
s
,
s
u
ch
as
r
ailway
p
o
wer
co
n
d
itio
n
er
s
(
R
PC
)
[
2
9
]
–
[
3
2
]
an
d
ac
tiv
e
p
o
wer
q
u
ality
co
m
p
en
s
ato
r
s
(
APQC
)
[
3
3
]
,
h
av
e
d
em
o
n
s
tr
ated
p
o
ten
tial
in
ad
d
r
ess
in
g
p
o
wer
q
u
ality
i
s
s
u
es.
W
h
ile
R
P
C
s
ef
f
ec
tiv
ely
c
o
m
p
e
n
s
ate
f
o
r
NS
C
,
h
ar
m
o
n
ics,
an
d
lo
w
p
o
we
r
f
ac
to
r
s
,
th
e
y
ar
e
lim
ited
b
y
th
eir
co
m
p
lex
ity
a
n
d
lack
o
f
f
lex
ib
ilit
y
.
T
h
e
h
y
b
r
i
d
r
ailway
p
o
wer
co
m
p
en
s
ato
r
(
HR
P
C
)
[
3
4
]
–
[
3
6
]
,
wh
ich
in
teg
r
ates
R
P
C
s
with
p
ass
iv
e
f
ilter
s
o
r
SVC
s
,
o
f
f
e
r
s
s
o
m
e
im
p
r
o
v
em
en
t
in
p
o
we
r
q
u
ality
.
Ho
wev
e
r
,
HR
PC
s
s
t
ill
f
ac
e
ch
allen
g
es,
s
u
ch
as
co
n
tr
o
l
co
m
p
le
x
ity
,
o
v
er
co
m
p
en
s
atio
n
,
an
d
r
eso
n
an
ce
,
wh
ich
d
e
g
r
ad
e
s
y
s
tem
p
er
f
o
r
m
a
n
ce
[
3
7
]
.
No
tab
ly
,
m
o
s
t
o
f
th
ese
s
o
lu
tio
n
s
f
ail
to
m
itig
ate
v
o
ltag
e
s
ag
s
r
esu
ltin
g
f
r
o
m
s
in
g
le
-
p
h
ase
o
r
th
r
ee
-
p
h
ase
f
a
u
lts
in
r
ailway
s
y
s
tem
s
.
T
h
e
u
n
if
ied
p
o
wer
q
u
ality
c
o
n
d
itio
n
er
(
UPQC
)
is
a
p
r
o
m
is
in
g
alter
n
ativ
e
f
o
r
r
eso
lv
i
n
g
p
o
wer
q
u
ality
p
r
o
b
lem
s
i
n
th
e
AC
elec
tr
if
icatio
n
s
y
s
tem
o
f
r
ailway
tr
ac
tio
n
.
B
y
em
p
lo
y
in
g
s
er
ies
an
d
p
ar
allel
co
n
v
er
ter
s
,
UPQC
ca
n
ad
d
r
ess
v
o
ltag
e
a
n
d
c
u
r
r
en
t
d
is
tu
r
b
a
n
ce
s
wh
ile
m
itig
atin
g
h
ar
m
o
n
ic
d
is
to
r
tio
n
s
.
R
ec
en
t
s
tu
d
ies
h
av
e
f
o
c
u
s
ed
o
n
d
esig
n
in
g
V/
V
-
co
n
n
ec
ted
UPQC
to
elim
in
ate
h
ar
m
o
n
ics
an
d
NSC
in
r
ai
lway
s
y
s
tem
s
[
3
8
]
.
Oth
er
r
esear
ch
h
as
em
p
h
asized
in
teg
r
atin
g
r
e
n
ewa
b
le
e
n
er
g
y
s
o
u
r
ce
s
a
n
d
e
n
er
g
y
s
to
r
ag
e
s
y
s
tem
s
in
to
UPQC
d
esig
n
s
to
en
h
an
ce
p
o
wer
q
u
ality
an
d
u
tili
ze
en
er
g
y
r
ec
o
v
er
ed
d
u
r
in
g
b
r
ak
i
n
g
o
p
er
a
tio
n
s
[
3
9
]
.
Mo
d
er
n
r
esear
ch
tr
en
d
s
also
h
ig
h
lig
h
t
th
e
p
o
te
n
tial
o
f
UPQC
f
o
r
im
p
r
o
v
in
g
r
ailway
p
o
we
r
q
u
ality
th
r
o
u
g
h
in
tellig
en
t
co
n
tr
o
l
s
y
s
tem
s
.
Ar
tific
ial
in
tellig
en
ce
(
AI
)
b
ased
co
n
tr
o
l
tech
n
iq
u
es
h
av
e
s
h
o
wn
p
r
o
m
is
e
in
en
h
an
cin
g
s
y
s
tem
p
er
f
o
r
m
a
n
ce
,
r
ed
u
cin
g
h
ar
m
o
n
ics,
an
d
im
p
r
o
v
in
g
o
v
er
all
p
o
wer
q
u
ality
[
4
0
]
,
[
4
1
]
.
Ho
wev
er
,
th
e
h
ig
h
co
s
t
o
f
UPQC
,
esp
ec
ially
f
o
r
h
ig
h
-
v
o
ltag
e
th
r
ee
-
p
h
ase
s
y
s
tem
s
,
p
o
s
es
a
s
ig
n
if
ican
t
b
ar
r
ier
to
wid
esp
r
ea
d
im
p
lem
en
tatio
n
.
T
h
is
s
tu
d
y
in
tr
o
d
u
ce
s
a
n
o
v
el
UPQC
ap
p
licatio
n
tailo
r
ed
f
o
r
r
ailway
s
y
s
tem
s
,
s
p
ec
if
ically
d
esig
n
ed
f
o
r
c
o
n
n
ec
tio
n
t
o
th
e
lo
w
-
v
o
l
tag
e
s
id
e
n
e
ar
t
h
e
lo
a
d
to
en
h
an
ce
c
o
n
tr
o
l
an
d
co
m
p
en
s
at
io
n
ef
f
icien
cy
.
T
h
e
p
r
o
p
o
s
ed
UPQC
ef
f
ec
tiv
ely
r
ed
u
ce
s
cu
r
r
en
t
im
b
ala
n
ce
an
d
h
ar
m
o
n
ics
wh
ile
m
ai
n
tain
i
n
g
v
o
ltag
e
s
tab
ilit
y
d
u
r
in
g
s
in
g
le
-
p
h
ase
an
d
th
r
ee
-
p
h
ase
f
au
lts
in
t
h
e
p
o
wer
g
r
id
.
An
in
-
d
ep
th
a
n
aly
s
is
an
d
c
o
n
tr
o
l
s
y
s
tem
d
esig
n
f
o
r
t
h
e
UPQC
d
em
o
n
s
tr
ate
it
s
ab
ilit
y
to
ef
f
icien
tly
m
itig
at
e
p
o
wer
q
u
ality
is
s
u
es
with
h
ig
h
p
r
ec
is
io
n
.
T
h
e
r
esu
lts
o
f
MA
T
L
AB
s
im
u
latio
n
v
alid
ate
th
e
p
er
f
o
r
m
an
ce
o
f
th
e
p
r
o
p
o
s
ed
UPQC
in
im
p
r
o
v
in
g
p
o
wer
q
u
ality
an
d
o
p
er
atio
n
al
s
tab
ilit
y
in
r
ail
way
s
y
s
tem
s
.
2.
P
RO
P
O
SE
D
SYS
T
E
M
2
.
1
.
E
lect
ric
ra
ilwa
y
s
y
s
t
em
wit
h UP
Q
C
Fig
u
r
e
1
s
h
o
ws
s
ch
em
atic
d
iag
r
am
o
f
th
e
p
r
o
p
o
s
ed
co
m
p
en
s
ato
r
d
esig
n
ed
to
b
alan
ce
cu
r
r
en
ts
an
d
r
eg
u
late
v
o
ltag
e
with
in
th
e
r
ailway
elec
tr
if
icatio
n
s
y
s
tem
.
I
t
d
ep
icts
th
e
co
n
n
ec
tio
n
o
f
tr
ac
tio
n
s
u
b
s
tatio
n
s
to
th
e
p
o
wer
g
r
id
at
th
e
p
o
in
t
o
f
co
m
m
o
n
co
u
p
lin
g
(
PC
C
)
th
r
o
u
g
h
a
V/V
tr
an
s
f
o
r
m
er
.
T
h
e
co
m
p
en
s
ato
r
em
p
lo
y
ed
in
th
is
s
tu
d
y
is
th
e
UPQC
,
wh
ich
is
in
s
talled
b
etwe
en
th
e
tr
ac
tio
n
s
id
e
an
d
th
e
lo
w
-
v
o
ltag
e
s
id
e
o
f
th
e
V/V
tr
an
s
f
o
r
m
er
to
ac
h
iev
e
cu
r
r
en
t b
alan
cin
g
an
d
v
o
ltag
e
r
eg
u
latio
n
.
Fig
u
r
e
2
p
r
o
v
id
es a
d
etailed
v
iew
o
f
th
e
UPQC
co
n
f
ig
u
r
atio
n
tailo
r
ed
s
p
ec
if
ically
f
o
r
th
ese
p
u
r
p
o
s
es in
th
e
r
ailway
s
y
s
tem
.
I
n
co
n
v
en
tio
n
al
p
r
ac
tice,
th
e
V/V
tr
an
s
f
o
r
m
er
in
tr
ac
tio
n
s
u
b
s
tatio
n
s
s
tep
s
d
o
wn
th
e
th
r
ee
-
p
h
ase
115
k
V
f
r
o
m
th
e
s
o
u
r
ce
s
y
s
tem
to
two
s
in
g
le
-
p
h
ase
tr
ac
tio
n
f
ee
d
er
s
o
p
er
atin
g
at
2
5
k
V.
T
h
e
UPQC
co
m
p
r
is
es
two
co
n
v
er
ter
s
th
at
s
h
ar
e
a
DC
-
lin
k
ca
p
ac
ito
r
,
wh
ich
h
elp
s
m
ain
tain
a
s
tab
le
DC
-
lin
k
v
o
ltag
e.
On
e
co
n
v
er
ter
,
ca
lled
th
e
s
er
ies
co
n
v
er
ter
,
is
lin
k
ed
to
th
e
tr
ac
tio
n
f
ee
d
er
th
r
o
u
g
h
a
th
r
ee
-
p
h
ase
tr
an
s
f
o
r
m
er
,
wh
ile
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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2
0
8
8
-
8
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8
I
n
t J E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
15
,
No
.
5
,
Octo
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e
r
20
25
:
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4
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th
e
o
th
er
,
th
e
s
h
u
n
t
co
n
v
er
ter
,
is
co
n
n
ec
ted
in
p
ar
allel
to
th
e
f
ee
d
er
v
ia
a
s
ep
ar
ate
th
r
ee
-
p
h
ase
s
tep
-
d
o
wn
tr
an
s
f
o
r
m
er
.
As
illu
s
tr
ated
in
Fig
u
r
e
2
,
th
e
s
h
u
n
t
co
n
v
er
ter
is
s
tr
ateg
ically
p
lace
d
clo
s
e
to
th
e
lo
ad
,
wh
ich
s
er
v
es
as
th
e
p
o
wer
s
u
p
p
ly
s
tatio
n
f
o
r
tr
ain
s
,
wh
ile
th
e
s
er
ies
co
n
v
er
ter
is
p
o
s
itio
n
ed
n
ea
r
th
e
V/V
tr
an
s
f
o
r
m
er
.
T
h
is
co
n
f
ig
u
r
atio
n
is
in
ten
tio
n
al,
as
th
e
s
h
u
n
t
co
n
v
er
ter
is
well
-
s
u
ited
f
o
r
m
itig
atin
g
cu
r
r
en
t
im
b
alan
ce
s
ca
u
s
ed
b
y
v
ar
iab
le
lo
ad
s
,
wh
ile
th
e
s
er
ies
co
n
v
er
ter
is
d
esig
n
ed
to
s
h
ield
th
e
lo
ad
s
f
r
o
m
v
o
ltag
e
f
lu
ctu
atio
n
s
o
r
ig
in
atin
g
f
r
o
m
th
e
p
o
wer
s
o
u
r
ce
.
B
y
em
p
lo
y
in
g
an
ef
f
ec
tiv
e
co
n
tr
o
l
s
tr
ateg
y
,
th
e
UPQC
ca
n
d
y
n
am
ically
ad
ju
s
t
th
e
o
u
tp
u
t
cu
r
r
en
ts
an
d
v
o
ltag
es
o
f
b
o
th
co
n
v
er
ter
s
.
T
h
is
d
u
al
ca
p
ab
ilit
y
allo
ws
th
e
s
er
ies
co
n
v
er
ter
to
ad
d
r
ess
v
o
ltag
e
s
ag
s
at
th
e
lo
ad
wh
ile
th
e
s
h
u
n
t
co
n
v
er
ter
co
m
p
en
s
ates
f
o
r
cu
r
r
en
t
im
b
alan
ce
s
,
th
er
eb
y
s
ig
n
if
ican
tly
en
h
an
cin
g
th
e
o
v
er
all
s
y
s
tem
ef
f
icien
cy
an
d
s
tab
ilit
y
.
Fig
u
r
e
1
.
Sch
em
atic
d
iag
r
am
o
f
th
e
elec
tr
ic
r
ailway
s
y
s
tem
with
UPQC
Fig
u
r
e
2
.
C
o
n
f
ig
u
r
atio
n
o
f
th
e
elec
tr
ic
r
ailway
s
y
s
tem
with
UPQC
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2088
-
8
7
0
8
E
n
h
a
n
cin
g
s
o
u
r
ce
cu
r
r
en
ts
a
n
d
en
s
u
r
in
g
lo
a
d
v
o
lta
g
e
s
ta
b
i
lity in
…
(
K
itta
ya
S
o
msa
i
)
4433
2
.
2
.
P
rinciple o
f
o
pera
t
io
n o
f
t
he
UP
Q
C
T
h
e
test
s
etu
p
f
o
r
th
e
elec
tr
ic
r
ailway
s
y
s
tem
co
n
f
ig
u
r
atio
n
in
teg
r
ated
with
th
e
UPQC
is
s
h
o
wn
i
n
Fig
u
r
e
2
.
Fu
r
t
h
er
d
etails
ar
e
p
r
esen
ted
in
th
e
s
in
g
le
-
lin
e
d
iag
r
a
m
p
r
esen
ted
i
n
Fig
u
r
e
3
.
T
h
is
d
ia
g
r
am
r
ep
r
esen
ts
th
e
s
y
s
tem
c
o
m
p
o
n
en
ts
,
in
clu
d
in
g
th
e
p
o
wer
s
y
s
tem
,
th
e
V/V
tr
a
n
s
f
o
r
m
er
,
a
r
ailway
lo
a
d
co
n
s
is
tin
g
o
f
two
tr
ain
s
,
th
e
r
i
g
h
t
-
s
h
u
n
t U
PQC
d
ev
ice,
an
d
t
h
e
UPQC
co
n
tr
o
l sy
s
tem
.
T
h
e
m
ain
co
m
p
o
n
e
n
ts
o
f
th
e
UPQC
in
th
e
d
escr
ib
ed
co
n
f
ig
u
r
atio
n
ar
e
th
e
s
er
ies
an
d
s
h
u
n
t
co
n
v
er
ter
s
,
wh
ich
s
h
ar
e
a
DC
-
lin
k
ca
p
ac
ito
r
.
T
h
e
o
p
er
atio
n
al
m
ec
h
an
is
m
o
f
th
e
UPQC
f
o
r
ac
h
ie
v
in
g
cu
r
r
e
n
t
b
alan
cin
g
an
d
v
o
ltag
e
e
n
h
an
c
em
en
t
in
th
e
r
ailway
elec
tr
if
i
ca
tio
n
s
y
s
tem
is
o
u
tlin
ed
as
f
o
llo
ws.
T
h
e
s
er
ies
co
n
v
er
ter
o
p
e
r
ates
as
a
v
o
ltag
e
s
o
u
r
ce
c
o
n
v
e
r
ter
(
VSC
)
an
d
is
co
n
n
ec
ted
in
s
er
ies
with
th
e
tr
ac
tio
n
f
ee
d
er
.
I
ts
r
o
le
is
to
in
ject
an
u
n
b
alan
c
ed
s
er
ies
v
o
ltag
e
in
to
th
e
tr
a
ctio
n
f
ee
d
er
to
c
o
m
p
en
s
ate
f
o
r
u
n
b
alan
ce
d
lo
ad
v
o
ltag
es
an
d
to
r
eg
u
late
th
e
l
o
ad
v
o
ltag
e
to
th
e
r
eq
u
ir
ed
le
v
el.
Similar
ly
,
th
e
s
h
u
n
t
co
n
v
er
ter
,
also
a
VS
C
,
i
s
co
n
n
ec
ted
i
n
p
a
r
allel
with
th
e
tr
ac
tio
n
f
ee
d
er
.
I
ts
f
u
n
ctio
n
i
s
to
in
ject
u
n
b
ala
n
ce
d
c
u
r
r
en
t
s
in
to
th
e
tr
ac
tio
n
f
ee
d
er
,
th
er
e
b
y
co
m
p
en
s
atin
g
f
o
r
u
n
b
alan
ce
d
s
o
u
r
ce
c
u
r
r
en
t
s
at
th
e
P
C
C
,
wh
ile
also
m
ain
t
ain
in
g
th
e
DC
-
lin
k
v
o
ltag
e
at
th
e
d
esire
d
lev
el.
T
h
e
e
f
f
e
c
t
i
v
e
n
e
s
s
o
f
t
h
e
U
P
Q
C
d
e
p
e
n
d
s
h
e
a
v
i
l
y
o
n
t
h
e
c
o
n
t
r
o
l
s
t
r
a
t
e
g
i
e
s
i
m
p
l
e
m
e
n
t
e
d
f
o
r
i
t
s
o
p
er
atio
n
.
T
h
e
r
o
les
o
f
b
o
th
th
e
s
er
ies a
n
d
s
h
u
n
t c
o
n
v
er
ter
s
h
av
e
b
ee
n
clea
r
ly
d
ef
in
ed
,
p
r
o
v
id
in
g
th
e
b
asis
f
o
r
t
h
e
i
r
r
e
s
p
e
c
t
i
v
e
c
o
n
t
r
o
l
s
t
r
a
t
e
g
i
e
s
.
T
h
e
U
P
Q
C
e
m
p
l
o
y
s
t
w
o
d
i
s
t
i
n
c
t
c
o
n
t
r
o
l
s
t
r
a
t
e
g
i
e
s
:
o
n
e
f
o
r
t
h
e
s
e
r
i
e
s
co
n
v
er
te
r
an
d
an
o
th
er
f
o
r
th
e
s
h
u
n
t c
o
n
v
e
r
ter
.
B
y
e
f
f
ec
tiv
e
ly
co
o
r
d
in
atin
g
t
h
ese
s
tr
a
teg
ies,
th
e
UPQC
en
s
u
r
e
s
p
r
o
p
e
r
c
o
m
p
e
n
s
a
t
i
o
n
o
f
u
n
b
a
l
a
n
c
e
d
s
o
u
r
c
e
c
u
r
r
e
n
t
s
a
n
d
m
a
i
n
t
a
i
n
s
r
e
g
u
l
a
t
e
d
v
o
l
t
a
g
e
s
w
i
t
h
i
n
t
h
e
r
a
i
l
w
a
y
elec
tr
if
icatio
n
s
y
s
tem
.
As
s
h
o
wn
in
Fig
u
r
e
3
,
th
e
cu
r
r
en
t
o
r
ig
in
atin
g
f
r
o
m
th
e
s
o
u
r
ce
an
d
p
ass
in
g
th
r
o
u
g
h
th
e
s
o
u
r
ce
r
esis
tan
ce
an
d
in
d
u
ctan
ce
is
d
en
o
ted
as
.
T
h
e
v
o
ltag
e
p
r
o
v
id
ed
to
th
e
tr
ac
tio
n
s
tatio
n
,
d
en
o
ted
as
,
is
r
ed
u
ce
d
v
ia
a
V/V
tr
an
s
f
o
r
m
er
with
a
tr
an
s
f
o
r
m
atio
n
r
atio
o
f
.
Fo
r
th
e
s
er
ies
co
n
v
er
ter
,
th
e
cu
r
r
en
t
p
ass
in
g
th
r
o
u
g
h
th
e
s
er
ies
tr
an
s
f
o
r
m
er
to
th
e
lo
ad
is
d
en
o
ted
as
,
wh
ile
th
e
cu
r
r
en
t
en
ter
in
g
th
e
s
er
ies
co
n
v
er
ter
is
r
ep
r
esen
ted
b
y
.
T
h
e
v
o
ltag
e
f
r
o
m
th
e
s
er
ies
co
n
v
er
ter
th
at
is
s
u
p
p
lied
to
th
e
lo
ad
is
.
T
h
is
v
o
ltag
e,
,
is
r
elate
d
to
th
e
o
u
tp
u
t
v
o
ltag
e
o
f
th
e
s
er
ies
co
n
v
er
ter
,
,
b
y
th
e
s
er
ies
tr
an
s
f
o
r
m
er
r
atio
.
I
t c
an
b
e
r
eg
u
lated
b
y
m
o
d
if
y
in
g
th
e
co
n
tr
o
l sig
n
al
.
Fo
r
th
e
s
h
u
n
t
co
n
v
er
ter
,
th
e
v
o
ltag
e
at
th
e
PC
C
is
r
ep
r
esen
ted
as
ℎ
,
wh
ile
th
e
cu
r
r
en
t
o
f
th
e
s
h
u
n
t
co
n
v
er
ter
th
at
p
ass
es
th
r
o
u
g
h
its
r
esis
tan
ce
ℎ
an
d
in
d
u
ctan
ce
ℎ
,
is
d
en
o
ted
as
ℎ
.
T
h
e
cu
r
r
en
t e
n
ter
in
g
th
e
s
h
u
n
t
co
n
v
er
ter
is
also
r
ep
r
esen
ted
as
ℎ
.
T
h
is
cu
r
r
en
t,
ℎ
,
is
u
tili
ze
d
to
co
m
p
en
s
ate
f
o
r
u
n
b
alan
ce
d
s
o
u
r
ce
cu
r
r
en
ts
an
d
to
r
ed
u
ce
h
ar
m
o
n
ics
in
th
e
s
u
p
p
ly
cu
r
r
en
t.
T
h
e
r
elatio
n
s
h
ip
b
etwe
en
ℎ
an
d
ℎ
is
d
ef
in
ed
b
y
th
e
s
h
u
n
t
tr
an
s
f
o
r
m
er
r
atio
ℎ
.
T
h
e
ad
ju
s
tm
en
t
o
f
ℎ
is
ac
h
iev
ed
b
y
co
n
tr
o
llin
g
th
e
v
o
ltag
e
ac
r
o
s
s
th
e
s
h
u
n
t
co
n
v
er
ter
,
ℎ
,
th
r
o
u
g
h
th
e
co
n
tr
o
l
s
ig
n
al
ℎ
.
No
n
eth
eless
,
to
co
n
tr
o
l
th
e
v
o
ltag
e
ac
r
o
s
s
b
o
th
th
e
s
er
ies
an
d
s
h
u
n
t
co
n
v
er
ter
s
(
an
d
ℎ
)
,
it
is
ess
en
tial
to
d
ep
en
d
o
n
th
e
DC
v
o
ltag
e,
,
o
n
th
e
DC
s
id
e.
Ho
wev
er
,
co
n
tr
o
llin
g
th
e
v
o
ltag
e
ac
r
o
s
s
b
o
th
th
e
s
er
ies
an
d
s
h
u
n
t
co
n
v
er
ter
s
(
an
d
ℎ
)
r
elies
o
n
th
e
DC
v
o
ltag
e
o
n
th
e
DC
s
id
e.
Fig
u
r
e
3
.
Sin
g
le
-
li
n
e
d
iag
r
a
m
o
f
th
e
s
y
s
tem
3.
CO
NT
RO
L
ST
R
AT
E
G
I
E
S
O
F
UP
Q
C
T
h
e
UPQC
co
n
tr
o
l
s
y
s
tem
em
p
lo
y
s
v
ar
io
u
s
th
eo
r
etica
l
ap
p
r
o
ac
h
es,
in
clu
d
in
g
in
s
tan
tan
eo
u
s
p
o
wer
th
eo
r
y
[
4
2
]
,
in
s
tan
tan
eo
u
s
s
y
m
m
etr
ical
co
m
p
o
n
en
ts
th
eo
r
y
[
4
3
]
,
an
d
s
y
n
ch
r
o
n
o
u
s
r
o
tatin
g
r
ef
er
en
ce
f
r
am
e
th
eo
r
y
[
4
4
]
.
T
h
is
s
tu
d
y
,
h
o
wev
er
,
f
o
cu
s
es
s
p
ec
if
ically
o
n
r
ed
u
cin
g
u
n
b
alan
ce
d
s
o
u
r
ce
cu
r
r
en
ts
u
s
in
g
in
s
tan
tan
eo
u
s
p
o
wer
th
eo
r
y
an
d
ac
h
iev
in
g
v
o
ltag
e
r
eg
u
latio
n
th
r
o
u
g
h
th
e
s
y
n
ch
r
o
n
o
u
s
r
o
tatin
g
r
ef
er
en
ce
f
r
am
e
th
eo
r
y
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8
7
0
8
I
n
t J E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
15
,
No
.
5
,
Octo
b
e
r
20
25
:
4
4
3
0
-
4
4
4
4
4434
3
.
1
.
Co
ntr
o
l o
f
s
hu
nt
co
nv
er
t
er
T
h
e
s
h
u
n
t
co
n
v
er
ter
is
in
ch
ar
g
e
o
f
co
r
r
ec
tin
g
u
n
b
alan
ce
d
s
o
u
r
ce
cu
r
r
en
ts
an
d
m
ain
tain
in
g
th
e
DC
-
lin
k
v
o
ltag
e
at
th
e
d
esire
d
lev
el.
Ad
d
itio
n
ally
,
it
ca
n
f
ilter
o
u
t
h
ar
m
o
n
ic
cu
r
r
en
ts
.
T
h
e
in
s
tan
tan
eo
u
s
p
o
wer
th
eo
r
y
o
r
th
e
p
-
q
th
eo
r
y
,
wh
ich
h
as
b
ee
n
p
r
ev
io
u
s
ly
ap
p
lied
in
D
-
STAT
C
OM
d
ev
ices
f
o
r
h
ar
m
o
n
ic
f
ilter
in
g
an
d
im
p
r
o
v
in
g
p
o
wer
q
u
ality
,
is
n
o
w
u
tili
ze
d
to
co
n
tr
o
l th
e
s
h
u
n
t c
o
n
v
er
ter
in
th
is
UPQC
.
On
e
o
f
th
e
p
r
im
ar
y
u
s
es o
f
th
e
p
-
q
th
eo
r
y
is
to
ad
d
r
ess
u
n
wan
ted
cu
r
r
en
ts
,
s
u
ch
as h
ar
m
o
n
ic
an
d
u
n
b
alan
ce
d
cu
r
r
en
ts
.
[
0
]
=
√
2
3
[
1
2
1
2
1
2
1
−
1
2
−
1
2
0
√
3
2
−
√
3
2
]
[
]
(
1
)
[
0
]
=
√
2
3
[
1
2
1
2
1
2
1
−
1
2
−
1
2
0
√
3
2
−
√
3
2
]
[
]
(
2
)
[
]
=
[
−
]
[
]
(
3
)
Fig
u
r
e
4
illu
s
tr
ates
th
e
co
n
tr
o
l
s
tr
ateg
y
d
esig
n
ed
f
o
r
s
h
u
n
t
co
n
v
er
ter
.
T
h
is
ap
p
r
o
ac
h
u
tili
ze
s
th
e
p
-
q
th
eo
r
y
,
wh
ich
in
co
r
p
o
r
ates
th
e
0
tr
an
s
f
o
r
m
atio
n
o
r
C
lar
k
e
tr
an
s
f
o
r
m
atio
n
[
4
2
]
.
T
h
is
tr
an
s
f
o
r
m
atio
n
u
s
es
a
r
ea
l
m
atr
ix
to
co
n
v
er
t
th
r
ee
-
p
h
ase
v
o
ltag
es
an
d
cu
r
r
en
ts
in
to
0
ax
es,
as
d
ef
in
ed
in
eq
u
atio
n
s
(
1
)
an
d
(
2
)
.
T
h
e
lo
ad
r
ea
l
p
o
wer
(
)
is
d
iv
id
ed
in
to
its
m
ea
n
co
m
p
o
n
en
t
(
̅
)
an
d
o
s
cillatin
g
co
m
p
o
n
en
t
(
̃
)
.
Similar
ly
,
th
e
r
ea
ctiv
e
p
o
wer
o
f
th
e
lo
ad
(
)
is
d
iv
id
ed
in
to
its
m
ea
n
(
̅
)
an
d
o
s
cillatin
g
(
̃
)
co
m
p
o
n
en
ts
.
Fo
r
s
im
p
licity
,
th
is
s
tu
d
y
f
o
cu
s
es
o
n
a
th
r
ee
-
p
h
ase,
th
r
ee
-
wir
e
s
y
s
tem
,
wh
er
e
ze
r
o
-
s
eq
u
en
ce
v
o
ltag
e
an
d
cu
r
r
en
t
co
m
p
o
n
en
ts
ar
e
ab
s
en
t.
Un
d
er
th
is
co
n
d
itio
n
,
th
e
an
d
o
f
th
e
lo
ad
ca
n
b
e
d
er
iv
ed
f
r
o
m
(
3
)
.
I
n
th
is
r
esear
ch
,
th
e
s
h
u
n
t
co
n
v
er
ter
o
f
th
e
UPQC
co
r
r
ec
ts
f
o
r
th
e
co
m
p
o
n
en
ts
̃
an
d
̃
,
en
s
u
r
in
g
th
at
o
n
ly
th
e
̅
is
tak
en
f
r
o
m
th
e
p
o
wer
s
y
s
tem
.
As
a
r
esu
lt,
th
e
co
n
s
tan
t
in
s
tan
tan
eo
u
s
p
o
wer
co
n
tr
o
l
s
tr
ateg
y
p
r
o
v
id
es
o
p
tim
al
co
m
p
en
s
atio
n
f
o
r
p
o
wer
f
lo
w,
ev
en
in
th
e
p
r
esen
ce
o
f
n
o
n
-
s
in
u
s
o
id
al
o
r
u
n
b
alan
ce
d
s
y
s
tem
cu
r
r
en
ts
.
T
h
e
r
ea
l
p
o
wer
o
f
th
e
elec
tr
ic
r
ailway
s
y
s
tem
,
r
ep
r
esen
ted
as
a
n
o
n
lin
ea
r
lo
ad
in
Fig
u
r
e
2
,
m
u
s
t b
e
co
n
tin
u
o
u
s
ly
m
o
n
ito
r
ed
an
d
d
iv
id
ed
in
to
̅
an
d
̃
co
m
p
o
n
en
ts
u
s
in
g
a
m
ea
n
f
u
n
ctio
n
.
Ad
d
itio
n
ally
,
th
e
in
clu
s
io
n
o
f
a
DC
v
o
ltag
e
r
eg
u
lato
r
in
to
th
e
s
h
u
n
t
co
n
v
er
ter
co
n
tr
o
l
s
tr
ateg
y
,
as
s
h
o
wn
in
Fig
u
r
e
4
,
is
ess
en
tial.
A
s
m
all
q
u
an
tity
o
f
p
o
wer
(
̅
)
m
u
s
t b
e
d
r
awn
co
n
tin
u
o
u
s
ly
f
r
o
m
th
e
p
o
wer
s
y
s
tem
to
co
m
p
en
s
ate
f
o
r
th
e
lo
s
s
es
in
th
e
PW
M
co
n
v
er
ter
.
I
f
n
o
t,
th
e
DC
ca
p
ac
ito
r
wo
u
ld
s
u
p
p
ly
th
is
en
er
g
y
,
lead
in
g
to
its
g
r
ad
u
al
d
is
ch
ar
g
e.
T
h
is
h
ig
h
lig
h
ts
th
e
n
ee
d
to
m
ain
tain
th
e
DC
v
o
ltag
e
at
a
co
n
s
tan
t
lev
el
h
ig
h
er
th
an
th
e
p
ea
k
AC
-
b
u
s
v
o
ltag
e,
wh
ich
is
ac
h
iev
ed
u
s
in
g
a
PI
co
n
tr
o
ller
to
co
n
tr
o
l th
e
DC
v
o
ltag
e.
T
h
u
s
,
th
e
s
h
u
n
t
co
n
v
er
ter
m
u
s
t
s
u
p
p
ly
th
e
o
s
cillatin
g
co
m
p
o
n
en
ts
o
f
th
e
in
s
tan
tan
eo
u
s
ac
tiv
e
an
d
r
ea
ctiv
e
cu
r
r
en
ts
o
f
th
e
lo
ad
.
T
h
ese
cu
r
r
en
ts
ca
n
b
e
d
eter
m
in
ed
u
s
in
g
(
4
)
f
o
r
th
eir
r
ef
er
en
ce
v
alu
es
in
th
e
ax
is
.
T
h
e
r
ef
er
en
ce
cu
r
r
en
ts
ar
e
th
en
tr
an
s
f
o
r
m
ed
b
ac
k
in
to
th
e
ab
c
r
ef
er
en
ce
f
r
am
e,
as
d
escr
ib
ed
in
(
5
)
,
f
o
r
f
u
r
th
er
u
s
e
in
th
e
co
n
tr
o
l sy
s
tem
.
Fig
u
r
e
4
.
C
o
n
tr
o
l b
lo
c
k
d
iag
r
a
m
o
f
s
h
u
n
t c
o
n
v
er
ter
o
f
UPQC
[
ℎ
∗
ℎ
∗
]
=
1
2
+
2
[
−
]
[
−
̃
+
̅
̅
̅
̅
̅
̅
−
]
(
4
)
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2088
-
8
7
0
8
E
n
h
a
n
cin
g
s
o
u
r
ce
cu
r
r
en
ts
a
n
d
en
s
u
r
in
g
lo
a
d
v
o
lta
g
e
s
ta
b
i
lity in
…
(
K
itta
ya
S
o
msa
i
)
4435
[
ℎ
∗
ℎ
∗
ℎ
∗
]
=
√
2
3
[
1
0
−
1
2
√
3
2
−
1
2
−
√
3
2
]
[
ℎ
∗
ℎ
∗
]
(
5
)
T
h
e
g
ate
p
u
ls
es
wh
ich
r
eq
u
ir
ed
f
o
r
s
h
u
n
t
co
n
v
er
ter
ar
e
p
r
o
d
u
ce
d
b
y
h
y
s
ter
esis
cu
r
r
en
t
co
n
tr
o
l.
C
o
m
p
ar
in
g
b
etwe
en
th
e
f
u
n
d
am
en
tal
cu
r
r
en
t
(
ℎ
(
)
)
an
d
r
ef
er
en
ce
s
ig
n
al
cu
r
r
en
t
with
th
e
h
y
s
ter
esis
b
an
d
(
ℎ
(
)
∗
±
ℎ
)
is
u
s
ed
to
g
en
er
ate
th
e
g
ate
p
u
ls
es.
T
h
e
g
ate
p
u
ls
es
r
eq
u
ir
ed
f
o
r
th
e
s
h
u
n
t
co
n
v
er
ter
ar
e
g
en
er
ated
u
s
in
g
h
y
s
ter
esis
cu
r
r
en
t
co
n
tr
o
l.
T
h
is
m
eth
o
d
co
m
p
ar
es
th
e
ac
tu
al
f
u
n
d
am
en
tal
cu
r
r
en
t
ℎ
(
)
with
th
e
r
ef
er
en
ce
cu
r
r
en
t sig
n
al
with
in
a
s
p
ec
if
ied
h
y
s
ter
esis
b
an
d
(
ℎ
(
)
∗
±
ℎ
)
to
p
r
o
d
u
ce
th
e
g
ate
p
u
ls
es.
3
.
2
.
Co
ntr
o
l o
f
s
er
ies co
nv
er
t
er
T
h
e
s
er
ies
co
n
v
er
ter
is
in
c
h
a
r
g
e
o
f
c
o
m
p
en
s
atin
g
th
e
lo
ad
v
o
ltag
e
an
d
r
e
g
u
latin
g
it
to
th
e
d
esire
d
lev
el.
T
o
m
a
n
ag
e
v
o
ltag
e
i
m
b
alan
ce
s
an
d
m
ain
tain
s
tab
le
o
p
er
atio
n
al
v
o
ltag
e
,
th
is
s
tu
d
y
ap
p
lies
th
e
s
y
n
ch
r
o
n
o
u
s
r
o
tatin
g
r
ef
er
en
ce
f
r
am
e
(
SR
F)
th
eo
r
y
.
T
h
e
SR
F
th
eo
r
y
in
v
o
l
v
es
tr
an
s
f
o
r
m
in
g
th
r
ee
-
p
h
ase
s
ig
n
als
(
abc
)
in
to
th
e
d
q
0
r
o
t
atin
g
r
e
f
er
en
ce
f
r
am
e
u
s
in
g
th
e
Par
k
tr
an
s
f
o
r
m
atio
n
.
T
h
is
tr
an
s
f
o
r
m
atio
n
r
elies
o
n
th
e
in
itial
alig
n
m
en
t
o
f
th
e
d
q
0
f
r
am
e
at
tim
e
t
=
0
,
co
r
r
e
s
p
o
n
d
in
g
to
th
e
p
o
s
itio
n
o
f
th
e
r
o
tatin
g
r
e
f
er
en
c
e
f
r
am
e
d
eter
m
in
ed
b
y
t
h
e
a
n
g
u
lar
v
elo
city
(
)
.
T
h
is
ap
p
r
o
ac
h
f
ac
ilit
ates
th
e
co
n
v
e
r
s
io
n
o
f
A
C
wav
ef
o
r
m
s
i
n
to
DC
s
ig
n
als.
Ho
wev
er
,
in
th
is
s
tu
d
y
,
th
e
ze
r
o
-
s
eq
u
en
ce
co
m
p
o
n
e
n
t
is
n
eg
lecte
d
,
as
th
e
f
o
cu
s
is
o
n
a
th
r
ee
-
p
h
ase
th
r
ee
-
wir
e
s
y
s
tem
.
T
h
e
u
n
b
alan
ce
d
v
o
ltag
e
in
th
e
elec
tr
ic
r
ailway
s
y
s
tem
is
p
r
im
ar
ily
d
u
e
to
th
e
NSC
with
in
th
e
s
y
n
ch
r
o
n
o
u
s
r
o
tatin
g
r
ef
er
en
ce
f
r
am
e,
p
o
s
in
g
a
s
ig
n
if
ican
t
ch
allen
g
e
f
o
r
v
o
ltag
e
co
m
p
en
s
atio
n
.
T
o
m
itig
ate
th
is
is
s
u
e,
th
e
s
er
ies
co
n
v
er
ter
o
f
th
e
UPQC
is
em
p
lo
y
ed
to
co
m
p
en
s
ate
f
o
r
th
e
NSC
in
th
e
dq
d
o
m
ain
,
wh
ile
th
e
PS
C
in
th
e
dq
d
o
m
ain
is
em
p
lo
y
ed
to
co
n
tr
o
l th
e
lo
ad
v
o
ltag
e
to
th
e
d
esire
d
lev
el.
Fig
u
r
e
5
p
r
esen
ts
th
e
d
iag
r
am
o
f
th
e
s
er
ies
co
n
v
er
ter
co
n
tr
o
l.
I
n
th
is
d
iag
r
am
,
th
e
th
r
ee
-
p
h
ase
lo
ad
v
o
ltag
es
(
,
an
d
)
ar
e
tr
an
s
f
o
r
m
ed
in
to
dq
-
PS
C
(
(
+
)
an
d
(
+
)
)
an
d
dq
-
NSC
(
(
−
)
an
d
(
−
)
)
u
s
in
g
(
6
)
an
d
(
7
)
,
r
esp
ec
tiv
ely
.
T
h
e
o
r
ien
tatio
n
o
f
th
e
r
o
tatin
g
r
ef
er
en
ce
f
r
am
e
(
)
in
th
ese
eq
u
atio
n
s
is
d
eter
m
in
ed
b
y
a
p
h
ase
-
lo
ck
ed
lo
o
p
(
PLL
)
,
wh
ich
ca
lcu
lates th
e
an
g
u
lar
v
elo
city
o
f
th
e
v
o
ltag
e
(
)
.
[
(
+
)
(
+
)
0
(
+
)
]
=
2
3
[
c
os
(
)
c
os
(
−
2
3
)
c
os
(
+
2
3
)
s
in
(
)
−
s
in
(
−
2
3
)
−
s
in
(
+
2
3
)
1
2
1
2
1
2
]
[
]
(
6
)
[
(
−
)
(
−
)
0
(
−
)
]
=
2
3
[
c
os
(
−
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c
os
(
−
−
2
3
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c
os
(
−
+
2
3
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s
in
(
−
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−
s
in
(
−
−
2
3
)
−
s
in
(
−
+
2
3
)
1
2
1
2
1
2
]
[
]
(
7
)
Fig
u
r
e
5
.
C
o
n
tr
o
l b
lo
c
k
d
iag
r
a
m
o
f
s
er
ies co
n
v
er
ter
o
f
UPQC
C
er
tain
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,
co
n
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tin
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t
h
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p
h
ase
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o
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in
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d
s
,
th
is
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al
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o
s
cillate
at
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8
7
0
8
I
n
t J E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
15
,
No
.
5
,
Octo
b
e
r
20
25
:
4
4
3
0
-
4
4
4
4
4436
twice
th
e
f
r
eq
u
en
c
y
o
f
th
e
f
u
n
d
am
en
tal
f
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en
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y
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o
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e
a
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ap
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ly
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ag
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ig
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th
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ase
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it
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s
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late
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e
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m
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o
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d
th
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to
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[
(
+
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∗
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+
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=
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s
in
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(
−
2
3
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s
in
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−
2
3
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1
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os
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2
3
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s
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+
2
3
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1
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[
(
+
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∗
(
+
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∗
0
(
+
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(
8
)
[
(
−
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∗
(
−
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∗
(
−
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∗
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=
[
c
os
(
−
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s
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1
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os
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−
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2
3
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1
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[
(
−
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∗
(
−
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∗
0
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−
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∗
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(
9
)
T
h
e
s
er
ies
co
n
v
er
ter
c
o
n
tr
o
l
em
p
lo
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s
f
o
u
r
p
r
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p
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r
tio
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in
t
eg
r
al
(
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n
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s
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o
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o
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.
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h
e
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tp
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ce
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ig
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als
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th
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ig
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n
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ted
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ac
k
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o
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itiv
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ativ
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m
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en
ts
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r
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p
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ase
AC
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ig
n
als
th
r
o
u
g
h
(
8
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a
n
d
(
9
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,
r
esp
ec
tiv
ely
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te
th
at
f
o
r
a
t
h
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ase
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ze
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s
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ce
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m
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t
ca
n
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n
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lecte
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b
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ase
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ig
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ir
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e
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ce
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h
e
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ies
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n
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ter
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ir
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ate
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3
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3
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ased
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ated
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Fig
u
r
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3
,
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,
is
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r
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in
Fig
u
r
e
6
.
I
n
th
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eq
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t
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th
e
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ailway
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m
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e
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r
o
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ab
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u
r
e
6
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q
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ir
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z
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2088
-
8
7
0
8
E
n
h
a
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(
K
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4437
W
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ex
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Fig
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r
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6
,
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o
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an
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g
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(
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(
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1
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(
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(1
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h
e
s
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b
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n
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co
m
p
o
n
e
n
ts
.
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h
e
b
o
t
h
dq
-
PS
C
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d
dq
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NS
C
ax
es
o
f
th
e
v
o
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e
at
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ies
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ter
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ig
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al
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dq
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an
d
dq
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es
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o
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e
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e,
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n
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e
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atio
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.
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±
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=
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±
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(
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(1
2
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(
±
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=
(
±
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(
±
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−
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±
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±
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3
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As
s
h
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wn
in
(
1
2
)
th
r
o
u
g
h
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1
3
)
,
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ig
n
al
f
u
n
ctio
n
s
as
th
e
in
p
u
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ile
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e
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e
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u
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t
o
f
co
n
tr
o
l
s
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e
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r
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atin
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e
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l
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e
o
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th
e
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ies
c
o
n
v
e
r
ter
as
s
h
o
wn
in
Fig
u
r
e
7
.
As
m
e
n
tio
n
ed
ea
r
lier
,
th
e
u
n
b
alan
ce
d
tr
an
s
f
o
r
m
atio
n
o
f
th
r
ee
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p
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ase
v
o
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e
o
n
t
h
e
dq
-
PS
C
an
d
dq
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ax
es
r
esu
lt
s
in
th
e
cr
ea
tio
n
o
f
o
s
cillatin
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s
ig
n
als
twice
th
e
f
u
n
d
am
e
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tal
f
r
eq
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e
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cy
.
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c
e,
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tili
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g
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er
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g
m
eth
o
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s
b
ec
o
m
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l
to
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eg
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late
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is
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ad
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o
ltag
e.
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h
is
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er
ag
in
g
is
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p
r
ess
ed
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r
o
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h
a
co
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s
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t
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r
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ased
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th
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n
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o
l
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iag
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am
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icted
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Fig
u
r
e
7
an
d
th
e
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tem
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ar
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tlin
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s
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eg
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h
r
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r
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ce
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o
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n
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ller
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o
r
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v
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r
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a
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atica
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o
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o
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o
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th
e
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,
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in
[
4
5
]
,
w
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n
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e
ex
p
r
ess
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y
(
1
5
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=
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2
1
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(1
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I
n
th
is
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n
tex
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e
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k
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ile
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en
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n
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ies
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n
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ter
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im
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lify
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g
th
e
d
esig
n
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h
e
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o
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tr
o
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ased
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f
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r
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en
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s
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n
t
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ter
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ar
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eter
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e
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o
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e
co
n
t
r
o
l
s
y
s
tem
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ch
em
atic
as
s
h
o
wn
in
Fig
u
r
e
8
is
d
ev
elo
p
ed
.
B
ased
o
n
th
is
d
iag
r
am
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d
T
ab
le
1
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e
tr
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s
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er
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u
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o
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te
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n
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er
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o
m
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al
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n
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itio
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with
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A,
is
g
iv
e
n
in
(
1
6
).
(
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)
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×
100
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,
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0
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10
−
6
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100
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2
)
(
0
.
005
+
1
)
(1
6
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Fig
u
r
e
7
.
B
lo
ck
d
iag
r
am
o
f
lo
ad
v
o
ltag
e
c
o
n
tr
o
l
Fig
u
r
e
8
.
B
lo
ck
d
iag
r
am
o
f
D
C
v
o
ltag
e
co
n
tr
o
l
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8
7
0
8
I
n
t J E
lec
&
C
o
m
p
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n
g
,
Vo
l.
15
,
No
.
5
,
Octo
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r
20
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4438
T
o
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h
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4.
SI
M
UL
A
T
I
O
N
R
E
S
UL
T
S
T
h
is
s
ec
tio
n
p
r
esen
ts
th
e
r
esu
lts
o
f
test
in
g
a
U
PQ
C
f
o
r
im
p
r
o
v
in
g
u
n
b
alan
ce
d
cu
r
r
e
n
ts
an
d
v
o
ltag
e
s
tab
ilit
y
in
r
ailway
elec
tr
if
icatio
n
s
y
s
tem
u
s
in
g
MA
T
L
AB
s
im
u
latio
n
s
.
Fig
u
r
e
9
illu
s
tr
ates
th
e
test
s
y
s
tem
s
im
u
lated
u
s
in
g
MA
T
L
AB
,
with
th
e
p
ar
am
eter
s
d
etailed
in
T
a
b
le
1
.
Fo
u
r
ca
s
e
s
tu
d
i
es
wer
e
ev
alu
ate
d
:
i
)
in
teg
r
atio
n
o
f
UPQC
,
ii
)
i
n
cr
ea
s
ed
tr
ain
lo
ad
,
iii
)
s
in
g
le
p
h
ase
-
to
-
g
r
o
u
n
d
f
au
lt,
an
d
iv
)
u
n
b
alan
ce
th
r
ee
p
h
ase
-
to
-
g
r
o
u
n
d
f
au
lt.
R
esu
lts
h
ig
h
lig
h
t
UPQC
's
s
u
p
er
io
r
p
er
f
o
r
m
a
n
ce
,
with
d
etailed
an
a
ly
s
is
s
u
p
p
o
r
ted
b
y
g
r
ap
h
s
an
d
n
u
m
er
ical
d
ata
d
e
m
o
n
s
tr
atin
g
its
ef
f
ec
tiv
e
n
ess
in
en
h
a
n
cin
g
p
o
wer
q
u
ality
a
n
d
en
s
u
r
in
g
s
tab
ilit
y
ac
r
o
s
s
all
s
ce
n
ar
io
s
.
Fig
u
r
e
9
.
T
est s
y
s
tem
s
im
u
lated
u
s
in
g
MA
T
L
AB
4
.
1
.
I
nte
g
ra
t
io
n o
f
UP
Q
C
T
h
is
test
f
o
cu
s
es
o
n
ev
alu
atin
g
th
e
ca
p
ab
ilit
y
o
f
UPQC
in
m
an
ag
in
g
u
n
b
alan
ce
d
cu
r
r
e
n
ts
d
u
r
in
g
th
e
in
itial
s
tar
tu
p
p
h
ase
o
f
co
m
p
e
n
s
atio
n
.
Du
r
in
g
th
e
tim
e
in
ter
v
al
f
r
o
m
t
=
0
.
1
–
0
.
2
s
ec
o
n
d
s
,
th
e
s
y
s
tem
o
p
er
ates
with
o
n
ly
t
h
e
tr
ain
1
(
T
L
)
ac
tiv
e.
As
d
ep
icted
in
Fig
u
r
e
1
0
,
th
e
t
r
ain
1
d
r
aws
cu
r
r
en
t
f
r
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m
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ase
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o
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r
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r
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s
it
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r
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u
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p
h
ase
-
b
,
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ile
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h
ase
-
c
r
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ai
n
s
u
n
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d
.
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r
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g
th
is
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er
i
o
d
,
th
e
th
r
ee
-
p
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ase
s
u
p
p
ly
c
u
r
r
en
ts
e
x
h
ib
it
a
s
i
g
n
if
ican
t
im
b
alan
ce
,
r
ea
ch
in
g
1
0
0
%.
Fu
r
t
h
er
m
o
r
e,
t
h
e
s
y
s
tem
ex
p
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ie
n
ce
s
s
u
b
s
tan
tial h
ar
m
o
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ic
d
is
to
r
tio
n
,
with
th
e
to
tal
h
a
r
m
o
n
ic
d
is
to
r
tio
n
(
T
HD)
m
ea
s
u
r
ed
at
1
0
.
2
6
%.
Fig
u
r
e
1
0
.
Ma
n
ag
in
g
u
n
b
alan
c
ed
cu
r
r
e
n
ts
d
u
r
in
g
th
e
in
itial st
ar
tu
p
p
h
ase
o
f
co
m
p
en
s
atio
n
At
t=0
.
2
s
ec
o
n
d
s
,
th
e
UPQC
is
ac
tiv
ated
in
th
e
s
y
s
tem
.
S
im
u
latio
n
r
esu
lts
r
ev
ea
l
th
at
t
h
e
UPQC
ef
f
ec
tiv
ely
ad
d
r
ess
es
th
e
cu
r
r
e
n
t
im
b
alan
ce
b
y
in
jectin
g
th
r
e
e
-
p
h
ase
co
m
p
en
s
atin
g
cu
r
r
en
t
s
th
r
o
u
g
h
its
s
h
u
n
t
co
n
v
er
ter
,
as illu
s
tr
ated
in
Fig
u
r
e
1
1
.
C
o
n
s
eq
u
en
tly
,
th
e
th
r
e
e
-
p
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ase
s
u
p
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ly
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r
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ar
e
r
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to
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ed
to
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b
alan
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d
s
tate,
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cin
g
th
e
im
b
ala
n
c
e
p
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ce
n
tag
e
to
3
.
0
2
5
%,
as
d
ep
icted
in
Fig
u
r
e
1
0
at
t
=
0
.
2
–
0
.
4
s
ec
o
n
d
s
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J E
lec
&
C
o
m
p
E
n
g
I
SS
N:
2088
-
8
7
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8
E
n
h
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g
s
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ta
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lity in
…
(
K
itta
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S
o
msa
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)
4439
Mo
r
eo
v
er
,
th
e
UPQC
s
ig
n
if
ican
tly
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ed
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ce
s
h
ar
m
o
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d
is
to
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tio
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g
th
e
T
HD
to
4
.
8
9
%.
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ese
f
in
d
in
g
s
h
ig
h
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h
t
t
h
e
UPQC
's
ca
p
ab
ilit
y
to
en
h
an
ce
p
o
wer
q
u
ality
b
y
m
itig
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cu
r
r
en
t
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m
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ala
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ce
s
an
d
h
ar
m
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d
is
to
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n
s
,
ev
en
u
n
d
e
r
ch
allen
g
in
g
s
y
s
tem
co
n
d
itio
n
s
.
Fig
u
r
e
1
1
.
Sh
u
n
t c
o
n
v
er
te
r
cu
r
r
en
ts
d
u
r
in
g
th
e
in
itial st
ar
tu
p
p
h
ase
o
f
co
m
p
en
s
atio
n
4
.
2
.
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ncre
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s
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t
ra
in lo
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d
T
h
is
s
tu
d
y
ex
am
in
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h
e
e
f
f
ec
ts
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f
in
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