12
Instrument Transformers
Instru
ment Transfo
rmers
Bu
siness E
dg
e
The S
witchgear W
orks of Crom
pton Greaves is located on a 1,32,540 sq.m
trs. plot in Nashik on the M
umbai A
gra National
Highw
ay and is demarcated in four m
ain divisions: EH
V S
F6 G
as Sw
itchgear, EH
V Instrum
ent Transform
er, Medium
Voltage
Vacuum
Sw
itchgear and Lightning Arresters. O
perations comm
enced in 1980 with the m
anufacture of Medium
Voltage
Sw
itchgear, which w
as relocated from K
anjur Mum
bai Works.
A
spe
cialise
d
Bu
sine
ss U
nit
spe
arh
ea
ds
the
e
xpo
rt th
rust
for
in-h
ou
se
pro
du
cts a
s w
ell
as
care
fully
out-sourced synergestic products for supply to Trade, Industry, O
EM
s and Pow
er Utilities.
Our regional establishm
ents throughout India have factory-trained personnel to provide prompt after sales service, supporting
our service personnel located at the factory.
Glo
bal L
eadersh
ip
Today, C
rompton G
reaves is well on its w
ay to becoming a G
lobal Leader in the field of
Tra
nsm
ission
& D
istribu
tion
. In M
ay 2
00
5,
CR
OM
PT
ON
GR
EA
VE
S a
cqu
ired
the
en
tire
Pa
uw
els
Gro
up
, a
le
ad
ing
tra
nsfo
rme
r
manufacturer in E
urope. With this acquisition, it has
be
com
e
on
e
of
the
to
p
10
tra
nsfo
rme
r
manufacturers in the w
orld. To further augm
ent its
position in the Transm
ission & D
istribution sector,
CR
OM
PT
ON
GR
EA
VE
S has recently acquired tw
o
Hu
ng
aria
n
com
pa
nie
s. G
an
z T
ran
sele
ktro,
engaged in manufacture of E
HV
Transform
ers, Gas
Insulated Sw
itchgear, rotating machines and G
anz
Transverticum
, involved in the project business &
specializing in high-end engineering & substation
capabilities.
With
the
late
st acq
uisitio
n, th
e tu
rno
ver o
f
CR
OM
PT
ON
GR
EA
VE
S has crossed the U
S$ 1
billio
n m
ark; m
akin
g it th
e first tru
ly Ind
ian
mu
ltina
tion
al.
CR
OM
PT
ON
G
RE
AV
ES
h
as
ma
nu
factu
ring
facilitie
s on
all five
con
tine
nts
spanning - India, Belgium
, Ireland, US
A, C
anada,
Indonesia, Hungary. International business today
accounts for over 50% of the sales.
Cro
mp
ton
Gre
ave
s alre
ad
y po
ssesse
s the
distin
ction
of p
rod
ucin
g w
orld
-class, q
ua
lity
pro
du
cts tha
t are
glo
ba
lly com
pe
titive. T
he
acq
uisitio
n h
as g
iven
CR
OM
PT
ON
GR
EA
VE
S
acce
ss to
n
ew
te
chn
olo
gie
s –
7
65
kV
transformers, G
IS upto 300kV
. The integration
pro
cess n
ow
un
de
rwa
y will stre
ng
the
n th
e
technological capability of CR
OM
PT
ON
GR
EA
VE
S
and its subsidiaries and allow the C
RO
MP
TO
N
GR
EA
VE
S g
rou
p to
em
erg
e a
s lea
de
r at th
e
cuttin
g e
dg
e o
f Tra
nsm
ission
& D
istribu
tion
business on a global scale.
Business
EdgeInstrum
ent Transform
ers
Current
Transformers
(72.5 kV
TO 550
kV)
Intro
du
ction
A large quantity of C
rompton G
reaves Current T
ransformers upto 550
kV have been put into service in various environm
ents in over 60
countries since 1984 where they are operating satisfactorily.
Type C
T and T
ype IOS
K, C
Ts are of live tank type w
ith rated voltage of
72.5 to 550 kV.
All our C
urrent Transform
ers (72.5 to 550 kV) adhere to the requirem
ents
of the International quality standards and our quality system, environm
ent
managem
ent system, safety m
anagement system
are certified to ISO
9001–2000, ISO
14001 and ISO
18001 respectively.
Desig
n
Current T
ransformers (C
Ts) are used to transform
high voltage line
current to a low standard value.
In o
ur live
tan
k type
of cu
rren
t tran
sform
ers, th
e p
rima
ry win
din
g
consists of aluminium
sections accomm
odated in the top housing. The
primary w
inding is rigid, concentric and distributed uniformly around the
insulated secondary winding in order to have optim
um m
echanical
endurance against short circuit forces. Fig.1 show
s the basic construction
of a CT
. The C
Ts can be equipped w
ith single or multiple prim
ary turns.
Fig.3 show
s a schematic diagram
of the connections. The prim
ary
windings are term
inated on the sides of the top housing with provisions
for convenient primary ratio changeover.
The cores and secondary w
indings are enclosed in a well contoured,
rigid aluminium
shell which is fully insulated from
the top housing. The
seco
nd
ary le
ad
s are
take
n to
the
ba
se o
f the
CT
thro
ug
h a
n o
il
impregnated paper (O
IP) insulated condenser bushing. T
he insulation
structure is specially designed to have a uniform drop of electric field
radially as well as longitudinally across the bushing. T
his is achieved by
specially contoured electrodes, uniform insulation around the electrodes
and fine potential grading along the bushing. High quality insulating kraft
paper is used for insulation. The paper insulation is dried under heat
and vacuum and im
pregnated with oil to achieve excellent insulation as
well as ageing properties. T
he fully assembled C
Ts are dried and oil
filled under vacuum in evacuated heating cham
bers.
Co
nstru
ction
Brow
n glazed porcelain Insulator with shed profile as per IE
C 815 is
used. Gray porcelains or variant shed profiles can also be supplied on
order. The porcelains are cem
ented to aluminium
alloy flanges on both
sides with portland cem
ent for providing optimum
mechanical strength.
The top housing is m
ade of corrosion resistant aluminium
alloy, form
fitted to the internal active body. The insulated prim
ary and secondary
windings are assem
bled in the top housing. Prim
ary terminals, w
ith ratio
changeover arrangements are accessible on the sides. S
tainless steel
bellow m
ounted at the top compensates for expansion / contraction of
oil due to ambient tem
perature variations. Thus the C
T is herm
etically
sealed. The bellow
position viewed through the w
indow on the H
ood
indicates the operational status and the oil level in the CT
. An oil filling
plug is provided at the top of the bellow.
FIG
. 11A
LU
MIN
IUM
HO
OD
2S
TA
INL
ES
S S
TE
EL B
EL
LO
W
3C
OR
E W
ITH
SE
CO
ND
AR
Y
WIN
DIN
G
4P
RIM
AR
Y T
ER
MIN
AL
5A
LU
MIN
IUM
HO
US
ING
6P
OR
CE
LA
IN IN
SU
LA
TO
R
7C
ON
DE
NS
ER
BU
SH
ING
8O
IL F
ILL
ING
PL
UG
9A
LU
MIN
IUM
SH
EL
L
10
MU
LT
I TE
RM
INA
L M
ON
OB
LO
CK
11
SE
CO
ND
AR
Y T
ER
MIN
AL
BO
X
12
RA
TIN
G &
SC
HE
M. P
LA
TE
13
GL
AN
D P
LA
TE
14
AL
UM
INIU
M B
AS
E
15
OIL
SA
MP
LIN
G P
OIN
T
������
�� ��
����
��
��
�
���
The fully encapsulated C
T is im
pervious to rain, snow and ice and can
sustain considerable temperature variations.
High quality C
RG
O grade silicon steel, M
u-metal cores of w
ound ring
type are used. Upto 6 cores of various accuracy classes, burdens and
FIG
. 3
�
���
���
���
���
���
���
���
���
��
��
�
��
��
CX
– C
AP
AC
ITA
NC
E A
ND
TA
ND
ELT
A M
EA
SU
RIN
G T
ER
MIN
AL
.
FIG
. 2
����
���� �
���
��
��
��
��
��������������������R
ated Norm
al Current can be accom
modated in one C
T to m
eet different
me
terin
g a
nd
pro
tectio
n re
qu
irem
en
ts. Th
e se
con
da
ry win
din
g is
uniformly distributed over the circum
ference of the core. This m
inimises
the
rea
ctan
ce o
f the
win
din
g a
nd
he
lps in
ob
tain
ing
accu
rate
transformation ratio.
The C
T base structure is m
ade of Alum
inium A
lloy. The secondary
terminal box, oil sam
pling valve and earthing pads are provided on the
base. Main lifting lugs and m
ounting holes are also provided on the
base. To provide stability during lifting and for erecting up from
prone
position, two additional lugs are provided on the top housing.
Tests A
nd
Perfo
rman
ce
The perform
ance and reliability of these Current T
ransformers has been
verifie
d a
t ren
ow
ne
d in
tern
atio
na
l testin
g la
bo
rato
ries like
KE
MA
(Netherlands) and C
PR
I (India). The C
Ts are type tested for short circuit
performance, T
hermal S
tability Test, M
ultiple Chopped w
ave Impulse test,
wet Lightning Im
pulse Test, partial discharge etc. as per IE
C 44-1 - 1996.
Tran
spo
rt
All C
Ts a
re b
e tra
nsp
orte
d in
ho
rizon
tal p
ositio
n o
nly. F
or fu
rthe
r
details please refer to the instruction manual.
Main
tenan
ce
The product is self contained, m
aintenance free and does not require
spares. For regular and periodic checks on the equipm
ent, please refer
the instruction manual supplied w
ith the CT
s.
(72.5 kV
TO 550
kV)
Curre
nt Transfo
rmers
(72.5 kV
TO 550
kV)
Curre
nt Transfo
rmers
Optio
nals
TY
PE
DE
SIG
NA
TIO
N:
UN
ITC
TIO
SK
IOS
KIO
SK
IOS
KIO
SK
IOS
K
72
.5/1
40
/32
51
23
/23
0/5
50
14
5/2
75
/65
01
70
/32
5/7
50
24
5/4
60
/10
50
30
0/4
60
/10
50
42
0/6
30
/14
25
1.R
AT
ED
TH
ER
MA
L CU
RR
EN
T:
AU
PT
O 4000 (F
OR
k=1)
2.A
LTIT
UD
E:
mU
PT
O 1500
3.S
EIS
MIC
AC
CE
LER
AT
ION
:g
0.3 / 0.5
4.C
RE
EP
AG
E:
mm
/kV25/31
25/31/3525/31
2531/35
31/3531
These param
eters are typical values. For other specifications, please contact us.
1.
TY
PE
DE
SIG
NA
TIO
N:
UN
ITC
TIO
SK
IOS
KIO
SK
IOS
KIO
SK
IOS
KIO
SK
72
.5/1
40
/32
51
23
/23
0/5
50
14
5/2
75
/65
01
70
/32
5/7
50
24
5/4
60
/10
50
30
0/4
60
/10
50
42
0/6
30
/14
25
55
0/6
80
/15
50
2.A
PP
LICA
BLE
ST
AN
DA
RD
: IE
C 44-1(1996); IE
C 185
3.H
IGH
ES
T SY
STE
M V
OLTA
GE
:kV
72.5123
145170
245300
362 / 420550
4.O
NE
MIN
. PO
WE
R:
kV140
230275
325460
460630
680F
RE
QU
EN
CY
VO
LTA
GE
5.LIG
HT
NIN
G IM
PU
LSE
:kV
p325
550650
7501050
10501425
1550
6.S
WIT
CH
ING
IMP
ULS
E:
kVp
NA
8501050
1175
7.R
AT
ED
FR
EQ
UE
NC
Y :
Hz
50/60
8.A
MB
IEN
T T
EM
PE
RA
TU
RE
:°C
-25 TO
50
9.S
EIS
MIC
AC
CE
LER
AT
ION
:g
0.3/0.5
10.A
LTIT
UD
E:
mU
PT
O 1000
11.O
NE
MIN
. P.F
.V
OLT
AG
E O
N S
EC
ON
DA
RY
- ME
TE
RIN
G:
kV3
- PR
OT
EC
TIO
N:
kV3
12.R
AT
ED
PR
IMA
RY
CU
RR
EN
T:
A50 - 2000 - 4000
13.R
ATED SEC
ON
DAR
Y CU
RR
ENT
:A
1 OR
5
14.S
HO
RT
TIM
E T
HE
RM
AL
:kA
/s31.5 / 1 &
340 / 1 &
3 50 / 1 &
3 Sec.
50 / 1C
UR
RE
NT
/ DU
RA
TIO
Nsec.
sec.sec.
15.D
YN
AM
IC W
ITH
ST
AN
D:
kA78.75
100 125
125C
UR
RE
NT
16.C
AN
TILE
VE
R LO
AD
:kg
In accordance with IE
C 44-1
17.TO
TAL C
RE
EP
AG
E D
ISTA
NC
E:
mm
18103075
36254250
61257500
1050013750
18.A
RC
ING
DIS
TA
NC
E:
mm
7001280
12801345
20402325
31553800
19.D
IME
NS
ION
SL1
:m
m1530
20702070
21102960
34104275
5060L2
:m
m2175
27552755
27803755
42255250
6300A
3:
mm
600665
665665
825855
10601200
20.M
OU
NT
ING
DIM
SA
1:
mm
560560
560600
600650
700750
A2
mm
670645
645685
700750
800890
21.T
OT
AL W
EIG
HT
:kg
325450
450525
850950
14502400
22.Q
UA
NT
ITY
OF
OIL
:kg
80100
100110
210320
375700
23.O
IL LEV
EL IN
DIC
AT
ION
:—
BE
LLOW
LEV
EL IN
DIC
AT
OR
PR
OV
IDE
D A
T T
HE
TO
P
24.P
RE
SS
UR
E R
ELIE
F D
EV
ICE
:—
ST
AIN
LES
S S
TE
EL B
ELLO
W P
RO
VID
ED
AT
TH
E T
OP
25.P
RO
VIS
ION
FO
RC
OM
PE
NS
AT
ION
OF
OIL
:—
ST
AIN
LES
S S
TE
EL B
ELLO
W P
RO
VID
ED
AT
TH
E T
OP
VOLUME EXPANSION/CONTRACTION
26.T
YP
E O
F S
EC
ON
DA
RY
:—
CLIP
ON
ST
UD
TY
PE
TE
RM
INA
L BLO
CK
S
(72.5 kV
TO 550
kV)
Capacitive
Volta
ge Transfo
rmer
Mo
re
tha
n
15
00
0
Cro
mp
ton
G
rea
ve
s
Ca
pa
citiv
e
Vo
ltag
e
Tra
nsfo
rme
rs up
to 5
50
kV h
ave
be
en
pu
t into
service
in va
riou
s
environments in over 60 countries all over the w
orld since 1984 where
the
y are
op
era
ting
satisfa
ctorily.
Ou
r CV
Ts a
dh
ere
to th
e re
qu
irem
en
ts of th
e In
tern
atio
na
l qu
ality
stan
da
rds a
nd
ou
r qu
ality a
nd
en
viron
me
nt m
an
ag
em
en
t system
,
safe
ty ma
na
ge
me
nt syste
m a
re ce
rtified
to IS
O 9
00
1–
20
00
, ISO
14
00
1 a
nd
ISO
18
00
1 re
spe
ctively.
Desig
n A
nd
Co
nstru
ction
Fig
ure
4 sh
ow
s the
sche
ma
tic view
as w
ell a
s the
con
structio
n o
f a
sing
le sta
ck CV
T. E
ach
CV
T co
nsists o
f a co
up
ling
cap
acito
r (CC
)
wh
ich a
cts as a
volta
ge
divid
er a
nd
an
Ele
ctro M
ag
ne
tic Un
it (EM
U)
wh
ich tra
nsfo
rms th
e m
ed
ium
volta
ge
to sta
nd
ard
low
volta
ge
.
De
pe
nd
ing
on
the
system
volta
ge
the
CC
can
be
a sin
gle
or a
mu
lti
stack u
nit. T
he
CC
an
d th
e E
MU
are
ind
ividu
ally h
erm
etica
lly sea
led
to e
nsu
re a
ccura
te p
erfo
rma
nce
an
d h
igh
relia
bility.
Co
up
ling
Cap
acitor
Th
e C
ou
plin
g C
ap
acito
r (CC
) acts a
s a vo
ltag
e d
ivide
r an
d co
nve
rts
the
system
volta
ge
to a
me
diu
m vo
ltag
e. T
he
active
pa
rt of th
e C
C
con
sists of a
larg
e n
um
be
r of o
il imp
reg
na
ted
pa
pe
r (pa
pe
r an
d film
)
cap
acito
r ele
me
nts co
nn
ecte
d in
serie
s. Su
pe
rcale
nd
ere
d ca
pa
citor
tissue
pa
pe
r an
d p
ure
alu
min
ium
foils a
re u
sed
to m
ake
the
cap
acito
r
ele
me
nts
. Th
e c
ap
ac
itor e
lem
en
ts a
re p
res
se
d a
nd
he
ld in
insu
latin
g su
pp
orts to
en
sure
a sta
ble
cap
acita
nce
eve
n fo
r larg
e
tem
pe
ratu
re
va
riatio
ns
. T
he
e
lec
trica
l c
on
ne
ctio
ns
be
twe
en
the
cap
acito
r ele
me
nts a
re d
esig
ne
d fo
r a n
atu
ral fre
qu
en
cy
mu
ch a
bo
ve 6
00
KH
z in o
rde
r to a
void
inte
rfere
nce
with
carrie
r
com
mu
nica
tion
.
Th
e p
roce
ssed
cap
acito
r stack is a
ssem
ble
d in
side
a p
orce
lain
insu
lato
r with
corro
sion
resista
nt a
lum
iniu
m a
lloy e
nd
fitting
s. Bro
wn
glazed porcelain insulators with shed profile as per IE
C 815 are used.
Th
e in
sula
tors a
re ce
me
nte
d to
alu
min
ium
allo
y flan
ge
s for im
pro
ved
stren
gth
. Oil vo
lum
e ch
an
ge
s du
e to
tem
pe
ratu
re va
riatio
ns a
re
co
mp
en
sa
ted
b
y
a
sta
inle
ss
s
tee
l b
ello
w
ins
talle
d
at
the
up
pe
r en
d o
f the
CC
. Th
e u
nit is co
mp
lete
ly filled
with
de
ga
ssed
insu
late
d o
il un
de
r vacu
um
. Th
e b
ello
w is p
ressu
rised
by in
ert g
as
(from
the
top
surfa
ce) to
ma
inta
in a
po
sitive o
il pre
ssure
eve
n a
t
low
est a
mb
ien
t tem
pe
ratu
res. T
he
CV
T th
us h
as ve
ry low
PD
leve
ls
eve
n a
t low
am
bie
nt te
mp
era
ture
s.
Electro
mag
netic U
nit
Th
e E
lectro
ma
gn
etic U
nit (E
MU
) con
sists of a
me
diu
m vo
ltag
e
tran
sform
er, co
mp
en
satin
g re
acto
r, da
mp
ing
ele
me
nt a
nd
surg
e
pro
tectio
n d
evice
. Th
e u
nit is h
ou
sed
insid
e a
stee
l tan
k wh
ich is
1C
olla
psib
le H
.V. T
erm
ina
l
Ø3
0×
80
2H
oo
d C
ha
mb
er
3P
orc
ela
in F
lan
ge
4B
ello
w
5P
orc
ela
in In
su
lato
r
6O
il Fillin
g P
lug
(Fo
r EM
U)
7L
ifting
Lu
gs
8S
eco
nd
ary
Te
rmin
al B
ox
9S
urg
e A
rresto
r
10
Ind
uctiv
e V
olta
ge
Tra
nsf.
11
EM
U T
an
k
12
Da
mp
ing
De
vic
e
13
Oil S
am
plin
g V
alv
e (fo
r EM
U)
14
Ea
rthin
g P
ad
s (8
mm
TH
K)
15
Co
mp
en
sa
ting
Ch
oke
16
Oil L
eve
l Ind
ica
tor o
n E
MU
17
M.V
. Ta
p T
erm
ina
l
18
NH
F T
erm
ina
l
19
Ta
nk C
ove
r
20
Be
llow
Le
ve
l Ind
ica
tor
21
Ch
am
be
r Fo
r Ind
ica
tor
CA
PA
CIT
OR
VO
LT
AG
E T
RA
NS
FO
RM
ER
� � ��
��
�
����
��
��
� ��
���
�
�� �� � �� ��
�� �
FIG
. 4
Capacitive
Voltage
Transformer
(72.5 kV
TO 550
kV)
BO
TT
OM
VIE
WB
OT
TO
M V
IEW
A-
HV
Te
rmin
al
C1
-P
ri. Ca
pa
cita
nce
C2
-S
ec. C
ap
acita
nce
NH
F-
HF
Te
rmin
al
L-
Co
mp
en
sa
ting
Ch
oke
Tr
-In
term
ed
iate
Vo
ltag
e
Tra
ns
form
er
F-
HR
C F
use
Zd
-D
am
pin
g D
evic
e
V-
Va
risto
r
D-
Dra
in C
oil
S-
Su
rge
Arre
ste
r
ES
-E
arth
ing
Sw
itch
N-
Ne
utra
l Te
rmin
al O
f
Inte
rme
dia
te T
ran
sfo
rme
r
FIG
. 5
W
W
A
W
W
A
FIG
. 6
OIL
LE
VE
L IN
DIC
AT
OR
ON
EM
UB
EL
LO
W P
OS
ITIO
N IN
DIC
AT
OR
����
���
�
filled
with
insu
latin
g o
il lea
ving
a la
rge
ly dim
en
sion
ed
air cu
shio
n a
t
the
top
in o
rde
r to ta
ke ca
re o
f cha
ng
es in
the
oil vo
lum
e d
ue
to
fluctu
atio
ns in
the
am
bie
nt te
mp
era
ture
. An
oil le
vel in
dica
tor is
mo
un
ted
on
the
side
wa
ll of th
e ta
nk.
Th
e C
C u
nit is m
ou
nte
d o
n th
e E
MU
tan
k an
d th
e in
sula
ted
ea
rth
term
ina
l of th
e C
C (m
arke
d a
s ‘NH
F’ in
Fig
.4) is a
lso a
ccessib
le fo
r
con
ne
cting
to p
ow
er lin
e ca
rrier co
mm
un
icatio
n e
qu
ipm
en
t. A su
rge
arre
ster a
cross th
is term
ina
l an
d e
arth
serve
s as th
e su
rge
pro
tectio
n
de
vice. T
he
NH
F te
rmin
al m
ust a
lwa
ys be
con
ne
cted
to e
arth
if the
CV
T is n
ot co
nn
ecte
d to
carrie
r eq
uip
me
nt.
Th
e se
con
da
ry term
ina
l bo
x is pro
vide
d o
n th
e E
MU
tan
k. Se
con
da
ry
lea
do
uts, N
HF
lea
d a
nd
ea
rth le
ad
s are
all te
rmin
ate
d in
side
the
seco
nd
ary te
rmin
al b
ox. T
he
EM
U is ca
libra
ted
an
d a
dju
sted
at
factory for all burden and accuracy requirements. N
o site adjustments
or m
ea
sure
me
nts a
re n
ecce
ssary. T
he
EM
U is g
iven
ad
eq
ua
te
surfa
ce tre
atm
en
t for co
rrosio
n p
rote
ction
for life
lon
g se
rvice.
Main
tenan
ce
Th
e p
rod
uct is se
lf con
tain
ed
, ma
inte
na
nce
free
an
d re
qu
ires n
o
spa
res o
ver its e
ntire
life sp
an
. We
reco
mm
en
d re
gu
lar a
nd
pe
riod
ic
che
cks as p
er p
re-sp
ecifie
d sch
ed
ule
s (spe
cified
in th
e In
structio
n
Ma
nu
als su
pp
lied
with
the
CV
Ts).
Op
tion
als / Accesso
ries
•T
erm
ina
l Co
nn
ecto
r (Alu
min
ium
/Bim
eta
llic, NE
MA
or a
s pe
r
custo
me
r spe
cs)
•T
hre
e e
lem
en
t Ca
rrier P
rote
ction
De
vice L
eve
l (com
prisin
g
Dra
in C
oil, su
rge
Arre
ster &
Ea
rth S
witch
)
•C
ab
le G
lan
ds
� ����� �
�
�
�
�
� ��
������������ ��
���
���
��
��
��
� ����� �
�
1.
TY
PE
DE
SIG
NA
TIO
N:
UN
ITCVE
CVE
CVE
CVE
CVE
CVE
CVE
CVE
CVE
72.5
/325/5
0145/6
50/5
0145/6
50/5
0170/7
50/5
0245/1
050/5
0300/1
050/5
0420/1
425/5
0420/1
425/5
05
50
/15
50
/50
2.A
PP
LICA
BLE
ST
AN
DA
RD
S:
IEC
186 (1987), IEC
358 (1990); IEC
60044 - 5 (2004)
3.H
IGH
ES
T S
YS
TE
M V
OLT
AG
E:
kV72.5
123145
170245
300362
420550
4.O
NE
MIN
, PO
WE
R FR
EQ
UE
NC
Y V
OLTA
GE
:kV
140230
275325
460460
575630
680
5.LIG
HT
NIN
G IM
PU
LSE
:kV
p325
550650
7501050
10501300
14251550
6.S
WIT
CH
ING
IMP
ULS
E:
kVp
NA
850950
10501175
7.R
AT
ED
FR
EQ
UE
NC
Y:
Hz
50/60
8.A
MB
IEN
T T
EM
PE
RA
TU
RE
:°C
-25 TO
50
9.S
EIS
MIC
AC
CE
LER
AT
ION
:g
0.3/0.5
10.R
AT
ED
VO
LTA
GE
FA
CT
OR
:–
1.2 (CO
NT
) / 1.5 (30 SE
C)
11.O
NE
MIN
. PO
WE
R F
RE
QU
EN
CY
VO
LTA
GE
ON
SE
CO
ND
AR
Y:
kV3
12.S
EC
ON
DA
RY
VO
LTA
GE
:V
100, 100/√3, 110, 110/√
3 , 120 , 120/ √3.
13.T
OT
AL C
RE
EP
AG
E D
IST
AN
CE
:m
m1815
30753625
42506125
75009050
1050013750
14.E
QU
IVA
LEN
T C
AP
AC
ITA
NC
E:
pF8800
60006000
60004400
44003000
44003000
15.TO
TAL SIMU
LTANEO
US BU
RD
EN/AC
CU
RAC
Y:
–200V
A / C
L 0.5
16.T
OT
AL T
HE
RM
AL B
UR
DE
N:
VA
500VA
750VA
17.C
AN
TILE
VE
R LO
AD
:kg
125200
250
18.A
RC
ING
DIS
TA
NC
E:
mm
8201215
12151415
19302180
26302830
3810
19.T
OT
AL H
EIG
HT
(H)
:m
m1950
23502350
25503410
36554175
43705730
20.M
AX
IMU
M D
EP
TH
(A)
:m
m785
785785
785785
785850
850850
21.M
OU
NT
ING
DIM
EN
SIO
NS
(W)
:m
m450
450450
450450
450450
450450
22.T
OT
AL W
EIG
HT
:kg
315360
430450
575600
810825
950
23.Q
TY
OF
OIL
:kg
7590
95100
115125
200210
240
24.O
IL VO
LUM
E C
OM
PE
NS
ATIO
N (C
C U
NIT)
:–
ST
AIN
LES
S S
TE
EL B
ELLO
W
25.A
LTIT
UD
E:
mU
PT
O 1000
Optio
nals
TY
PE
DE
SIG
NA
TIO
N:
UN
ITC
VE
CV
EC
VE
CV
EC
VE
CV
EC
VE
CV
EC
VE
1.H
IGH
ES
T S
YS
TE
M V
OLT
AG
E:
kV72.5
123145
170245
300362
420550
2.V
OLT
AG
E F
AC
TO
R:
–1.9 F
OR
30 SE
C—
—
3.C
RE
EP
AG
E D
IST
AN
CE
:m
m/kV
25, 31, 3525, 31
25
4.TO
TAL SIMULTANEO
US BURDEN/ACCURACY:
–100 VA / CL 0.2
100 VA /CL 0.2100 VA /CL 0.2
These param
eters are typical values. For other specifications, please contact us.
(72.5 kV
TO 550
kV)
Capacitive
Volta
ge Transfo
rmer
Inductive Voltage
Transformer
For Outdoor
Use
(72.5 kV
To
420 kV
)
FIG
. 7In
trod
uctio
n
Cro
mp
ton
G
rea
ves
Ltd
. h
ave
m
an
ufa
cture
d
an
d
sup
plie
d
thousands of quality electrical products for the past six decades which
have excelled in various test and service environments around the w
orld.
Nearly 5000 Inductive V
oltage Transform
ers, type IVT
/VE
OT
, have been
supplied all over the world since 1986 and their perform
ance and reliability
has proven to be one of the best.
All our V
oltage Transform
ers (72.5 to 420 kV) adhere to the requirem
ents
of th
e q
ua
lity stan
da
rds a
nd
ou
r qu
ality syste
m, e
nviro
nm
en
t
managem
ent system, safety m
anagement system
are certified to ISO
900-2000, ISO
14001 and ISO
18001 respectively.
Desig
n
Voltage T
ransformers (V
Ts) are used to transform
high system voltages
(kV) to low
measurable values (V
olts).
Fig. 7 show
s the basic construction of the Inductive Voltage T
ransformer.
The high voltage w
inding consists of a multi-layered coil of insulated
copper wire. Inter-layer insulation is provided by O
il Impregnated P
aper
(OIP
). The high V
oltage (HV
) winding is w
ound over the low voltage
(LV) w
inding and assembled over a closed iron core m
aintained at ground
potential.
The V
Ts can be provided w
ith several metering and protection w
indings
and can be designed to provide any desired voltage output from the
secondary winding. S
econdary taps can be used to obtain multi-ratio
secondary voltage output.
The high voltage lead is brought to the bottom
tank (which houses the
windings) through an O
IP insulated condensor bushing in order to
maintain the accessible bottom
tank of the VT
at ground potential.
Uniform
potential gradient is obtained along the bushing by means of
contoured electrodes, uniform insulation and fine condensor grading.
High quality kraft paper is used to w
ind the bushings using a Wide B
and
Bushing W
inding machine. T
he paper insulation is dried under heat and
vacuum and then im
pregnated with oil to achieve excellent insulation as
well as ageing properties. T
he fully assembled V
Ts are dried and oil
filled under vacuum in evacuated heating cham
bers.
Co
nstru
ction
Th
e V
T h
ea
d is e
qu
ipp
ed
with
the
prim
ary te
rmin
al. T
he
he
ad
acco
mo
da
tes a
n o
il com
mu
nica
ting
type
stain
less ste
el b
ello
w to
compensate for changes in oil volum
e due to changes in the ambient
temperature. T
he bellow renders the V
T truly herm
etically sealed and,
at the same tim
e, removes any chances of abnorm
al internal pressure
variation. A w
indow is provided at the top to indicate the bellow
level
and thus the oil level in the VT
.
The porcelains are cem
ented to aluminium
alloy flanges on both sides
with portland cem
ent to provide optimum
mechanical strength. B
rown
1H
.V.T
ER
MIN
AL Ø
30×
80 M
M L
ON
G
2H
OO
D
3U
PP
ER
PO
RC
ELA
IN F
LA
NG
E
4P
OR
CE
LA
IN IN
SU
LA
TO
R
5C
ON
DE
NS
ER
BU
SH
ING
6S
EC
ON
DA
RY
BO
X
7E
PO
XY
MO
NO
BLO
CK
8S
EC
ON
DA
RY
TE
RM
INA
LS
9R
AT
ING
/SC
HE
MA
TIC
PLA
TE
10
GLA
ND
PLA
TE
11
C.R
.G.O
. CO
RE
12
OIL
SA
MP
LIN
G V
ALV
E
13
LIF
TIN
G L
UG
14
TA
NK
15
LO
WE
R P
OR
CE
LA
IN F
LA
NG
E
16
EA
RT
HIN
G P
AD
17
PR
IMA
RY
WIN
DIN
G
18
SE
CO
ND
AR
Y W
IND
ING
19
OIL
FIL
LIN
G P
LU
G
20
BE
LL
OW
���������
���
�������
������
� ����� �
���� ���!���
�
���
��
��
����
����
FIG
. 8
�����������"����
���#�� �
�
For Outdoor
Use
(72.5 kV
To
420 kV
)Inductive
Volta
ge Transfo
rmer
glazed porcelain of shed profile as per IEC
815 is used. Grey porcelains
or variant shed profiles can also be supplied against specific customer
requirement.
The bottom
tank is made of high quality sheet steel and shaped to
conform to the active part of the V
T. A
ll exposed ferrous parts are shot
blasted, spray galvanised, primer coated and finally painted w
ith high
quality polyurethane or epoxy paint in order to ensure excellent finish
and corrosion resistance. The bottom
tank accomodates the core, H
V
and LV w
indings and the secondary terminal leadouts. T
he tank is
equipped with secondary term
inal box with cover, earthing connection,
oil sampling valve and rating and schem
atic plate. The secondary leads
are brought out through multi-term
inal monoblocks into the secondary
terminal box for easy access. Lifting lugs and m
ounting holes are also
provided on the tank.
Tests A
nd
Perfo
rman
ce
Th
e p
erfo
rma
nce
an
d re
liab
ility of C
rom
pto
n G
rea
ves m
ake
Ind
uctive
V
olta
ge
T
ran
sform
ers
ha
s b
ee
n
verifie
d
by
type
testing at renowned laboratories like C
PR
I (India) KE
MA
Netherland.
Tran
spo
rt
All IV
Ts are transported in horizontal position except for 72.5 kV
IVT
which is transported vertically.
Main
tenan
ce
Th
e p
rod
uct is se
lf con
tain
ed
, ma
inte
na
nce
free
an
d d
oe
sno
t
require any spares throughout its service life. For regular and periodic
checks, please refer the instruction manual.
MO
UN
TIN
G D
ET
AIL
S
Inductive Voltage
Transformer
For Outdoor
Use
(72.5 kV
To
420 kV
)
These param
eters are typical values. For other specifications, please contact us.
1.
TY
PE
DE
SIG
NA
TIO
N:
UN
ITS
IVT
VE
OT
VE
OT
VE
OT
VE
OT
VE
OT
VE
OC
2.A
PP
LICA
BLE
ST
AN
DA
RD
: IE
C 44-2, 1997 (F
OR
ME
RLY
IEC
186, 1987)
IS 3156, 1992
3.H
IGH
ES
T S
YS
TE
M V
OLT
AG
E:
kV72.5
123145
170245
300420
4.O
NE
MIN
PO
WE
R F
RE
QU
EN
CY
:kV
140230
275325
460460
630W
ITH
ST
AN
D V
OLT
AG
E
5.1.2/50 μ
s IMP
ULS
E W
ITHS
TAN
D V
OLTA
GE
:kV
p325
550650
7501050
10501425
6.S
WIT
CH
ING
IMP
ULS
E:
--
--
--
8501050
7.R
AT
ED
FR
EQ
UE
NC
Y:
Hz
50/60
8.A
MB
IEN
T T
EM
PE
RA
TU
RE
:°C
-25 TO
50
9.S
EIS
MIC
AC
CE
LER
AT
ION
:g
0.3/0.5
10.R
AT
ED
VO
LTA
GE
FA
CT
OR
:-
1.2 (CO
NT
) / 1.5 (30 SE
C)
11.1 M
IN P
OW
ER
FR
EQ
UE
NC
Y W
ITH
ST
AN
D:
kV3
VO
LTA
GE
ON
SE
CO
ND
AR
Y W
IND
ING
S
12.S
EC
ON
DA
RY
VO
LTA
GE
:V
100,100/√3, 110, 110/√
3 , 120 , 120/√3
13.T
OT
AL C
RE
EP
AG
E D
IST
AN
CE
:m
m1810
30753625
42506125
750010500
14.A
RC
ING
DIS
TA
NC
E:
mm
7001100
13001400
20652325
3200
15.T
OT
AL S
IMU
LTA
NE
OU
S:
-300 V
A /
500 VA
/500 V
A /
500 VA
/500 V
A/
500 VA
/300 V
A /
BU
RD
EN
/ AC
CU
RA
CY
CL 0.5
CL 0.5
CL 0.5
CL 0.5
CL 0.5
CL 0.5
CL 0.5
15.T
OT
AL T
HE
RM
AL B
UR
DE
N:
VA
500 VA
750 VA
750 VA
1000 VA
1000 VA
1000 VA
750 VA
16.C
AN
TILE
VE
R LO
AD
:kG
125200
200200
250250
250
17.T
OT
AL H
EIG
HT
(WIT
HO
UT
SU
PP
OR
T:
mm
18102725
27253080
38004195
5930S
TR
UC
TU
RE
) (H)
18.T
OT
AL H
EIG
HT
UP
TO
HV
TE
RM
INA
L(H1 )
:m
m1810
23752375
26703800
41955450
19.M
AX
IMU
M W
IDT
H (A
):
mm
700790
790930
9801000
850
20.M
OU
NT
ING
DIM
EN
SIO
NS
(W)
:m
m375 ×
375450 ×
450450 ×
450600 ×
600550 ×
550600 ×
600650 ×
650
21.T
OT
AL W
EIG
HT
:kG
230400
400575
8701200
1250
22.Q
TY
OF
INS
ULA
TIN
G O
IL:
kG50
5050
100210
350360
23.P
RO
VIS
ION
FO
R C
OM
PE
NS
AT
ION
-S
TA
INLE
SS
ST
EE
L BE
LLOW
OF
OIL V
OLU
ME
EX
PA
NS
ION
24.TY
PE
OF S
EC
ON
DA
RY
TER
MIN
AL B
LOC
KS
:-
CLIP
ON
ST
UD
TY
PE
Optio
nals
TY
PE
DE
SIG
NA
TIO
N:
UN
ITS
IVT
VE
OT
VE
OT
VE
OT
VE
OT
1.
HIG
HE
ST
SY
ST
EM
VO
LTA
GE
:kV
72
.51
23
14
51
70
24
5
2.
VO
LTA
GE
FA
CT
OR
:-
1.9 FO
R 30 S
EC
3.
CR
EE
PA
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