GE OTCF User manual

Instruction Manual
© GE Grid Solutions
INSTRUCTION MANUAL NUMBER MI-ITR103
CAPACITOR VOLTAGE TRANS ORMER
MODEL OTC
VOLTAGE LEVEL: 72,5kV TO 800kV

Instruction Manual
© GE Grid Solutions
GE Grid Solutions
Av. Nossa Senhora da Piedade, 1021
37504-358 Itajuba - MG – Brazil
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AIB - 01 04/09/2018 TAA FES
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Owner Control Revision Date Prepared Approved

Instruction Manual
© GE Grid Solutions
Attention!
Anyone involved in he ranspor a ion, ins alla ion, commissioning, opera ion, and main enance of
OTCF Capaci or Vol age Transformers (CVT) should read hese ins ruc ions before aking any
ac ion.
Never work on high vol age equipmen wi hou firs having grounded i s me allic par s, since i is
inheren o capaci ances he possibili y of elec ric charges accumula ed wi h vol ages a le hal
levels. In addi ion, an ear h rod mus remain connec ed o he line erminal while an opera or
works on hese ransformers.
When an elec rical es is going o be performed, he person responsible for supervising he es
assumes responsibili y for carrying ou he es in a safe manner in accordance wi h curren
legisla ion. Af er he es , he opera or mus remove he ground rod so ha he equipmen is
ready for opera ion.
Note: To discharge high vol age equipmen effec ively proceed as follows:
A) Connec he ground rod o he line erminal ( his will shor circui he en ire uni and place he
line erminal in he ground po en ial) and,
B) Use o her(s) ground rod connec ed o any in ermedia e me al par for a minimum of 30
seconds o make sure here is no residual elec rical load on he uni .
This ransformer is manufac ured wi h con rolled process which guaran ees he highes level of
Quali y. To main ain his high-Quali y level hroughou he service life of he CVT i is of he
u mos impor ance ha all ins ruc ions in his manual be read and unders ood.
THE VERSIONS O OTC TRANS ORMERS TRANSPORTED IN VERTICAL POSITION CANNOT BE
STORED IN THE HORIZONTAL POSITION. DEPENDING ON THE PRODUCT VERSION, OTC -245,
OTC -420 AND OTC -550 MAY BE TRANSPORTED AT HORIZONTAL POSITION. EVEN OR THESE
CASES, THE TRANS ORMERS CAN NOT BE STORED IN A HORIZONTAL POSITION OR MORE THAN
OUR MONTHS. I THE TIME O TRANSPORTION AND STORAGE EXCEEDS THIS PERIOD, IT IS
MANDATORY TO UNPACK AND PUT THE TRANS ORMER INTO A VERTICAL POSITION,
ANCHORING ITS BASETANK TO THE GROUND. DO NOT ENERGIZE A TRANS ORMER I IT HAS
BEEN KEPT IN HORIZONTAL POSITION DURING MORE THAN OUR MONTHS.
Preliminary remarks
During receip of he CVT, i is impor an o check he unpacking carefully o con rol he packaging
condi ions and he CVT i self. Any irregulari y mus be no ed on he ranspor a ion documen s and
communica ions wi h responsible persons should be made shor ly.
The insula or may be delivered in porcelain, avoid fas movemen s ha may cause shocks and / or
blows.

Instruction Manual
© GE Grid Solutions
Index
1. SCHEMATIC DIAGRAM ................................................................................................................ 5
2. TRANSPORT, RECEPTION, UNPACKING AND STORAGE .................................................................... 6
2.1. Transport ........................................................................................................................... 6
2.2. Reception .......................................................................................................................... 7
2.3. Unpacking .......................................................................................................................... 7
2.4. Storage ............................................................................................................................ 11
3. ANCHORING ............................................................................................................................ 11
4. CONTACT SURFACES PREPARATION ............................................................................................ 11
5. CONNECTIONS AND ACCESORIES ............................................................................................... 12
5.1. Primary terminals ............................................................................................................. 12
5.2. Secondary terminal box..................................................................................................... 13
5.3. Secondary terminals ......................................................................................................... 13
5.4. H terminal ...................................................................................................................... 13
5.5. Terminal marking ............................................................................................................. 14
5.6. Protection of compensation reactor and drain coil .............................................................. 14
5.7. CVT grounding .................................................................................................................. 14
5.8. EMU potential grounding switch ........................................................................................ 15
5.9. Carrier grounding switch ................................................................................................... 15
5.10. Line trap assembly ........................................................................................................ 16
6. OIL LEVEL INDICATOR................................................................................................................ 16
7. INSPECTION BEFORE FIRST ENERGIZING ...................................................................................... 17
8. ON-SITE TESTS ......................................................................................................................... 17
8.1. On-site test methods ........................................................................................................ 18
8.2. Care and precaution .......................................................................................................... 18
8.3. Capacitance measurement ................................................................................................ 18
8.4. Voltage ratio measurement ............................................................................................... 23
8.5. GARTON effect ................................................................................................................. 24
8.6. Capacitance and dissipation factor with temperature variation ............................................ 25
9. MANTENANCE AFTER ENERGIZING ............................................................................................. 25
10. FINAL DISPOSAL OF THE TRANSFORMER PARTS AFTER LIFE TIME ............................................... 26

Instruction Manual
© GE Grid Solutions
1. SCHEMATIC DIAGRAM
The OTCF Capaci or Vol age Transformer (CVT) is an assembly of a capaci ive vol age divider (CD)
and an elec romagne ic uni (EMU). Depending on he ra ed vol age, he CD may con ain of one or
more capaci ive modules wi h an in ermedia e vol age erminal hrough a medium vol age
bushing which feeds he EMU.
Each capaci ive module con ains capaci ive elemen s impregna ed wi h syn he ic oil and is
herme ically sealed, a me allic bellows works as expansion chamber o compensa e varia ion of
volume of oil due o ambien empera ure changing.
When specified, each capaci ive module can be supplied wi h a manome er for indica ion of
in ernal pressure of oil.
The EMU is moun ed in a ank filled wi h mineral oil and is herme ically sealed hrough an air
cushion.
Figure below shows a ypical cross-sec ional view of an OTCF:
1
-
Primary terminal
2- Top cover to protect metallic bellows
3- Metallic bellows
4- Compression spring
5- Wire for voltage connection
6- Capacitive elements
- Insulator: porcelain or composite
8- Voltage divider
9- Bushing
10- Voltage divider LV connection
11- Ferroresonance suppression device
12- Secondary terminals
13- EMU oil level indicator
14- Secondary box
15- Intermediate transformer
16- Oil / air block
1 - Oil sample plug
18- Compensation reactor
19- EMU top cover

Instruction Manual
© GE Grid Solutions
2. TRANSPORT, RECEPTION, UNPACKING
AND STORAGE
2.1. Transport
The ransformer shall be ranspor ed in
he posi ion indica ed by he
manufac urer in an appropria e
packaging.
In general, he CVT wi h maximum
vol age up o 245 kV is ranspor ed in a
wooden box con aining he assembled
base uni (EMU and CD). For CVT above
245 kV, he equipmen is ranspor ed in
such a way ha he upper modules of
he CD are separa ed from he lower
module and EMU bu ranspor ed in he
same package oge her wi h all he
necessary hardware for he assembly of
he comple e uni (see 5.1). The CD
modules must be placed in an upright
position. Depending on the product
version, OTC -245, OTC -420 and OTC -
550 may be transported at horizontal
position. Even for these cases, the units
cannot be stored in a horizontal
position for more than 4 months. It the
time of transportation and storage
exceeds this period, it is mandatory to
unpack and put the transformer in a
vertical position, anchoring its basetank
to the ground.
The user mus carry and handle he CVT
carefully. The correc shipping posi ion is
marked on he packaging as shown in
he following examples.
Example of ver ical packaging
Example of horizon al packaging
IMPORTANT: The OTCF mus always be
ranspor ed wi h he op modules
disassembled from he EMU. When
originally it was transported in
horizontal position, all components in
an upright position, apart from versions
that are transported in a horizontal
position. Also, i shall be ranspor ed in
i s original packaging or in an
appropria e packaging.
OTCF ver ical packages canno be
s acked. For horizon al packages, he
s ack limi is one.

Instruction Manual
© GE Grid Solutions
ATTENTION! The CVT has fragile par s
(insula or, bellows, e c.) ha can be
damaged during ranspor a ion, by sea,
air or by road (being he road paved or
no ). The ranspor a ion and handling
shall be made wi h care. Sudden
movemen s can cause impac and
damage o he equipmen .
2.2. Reception
Whe her he shipmen is on
manufac urer’s or cus omer’s
responsibili y, he cus omer inspec or or
he service agen has o check he
following on receip of delivery:
If he cra es show any signals of impac ,
blows or frac ures, or if he ransformers
have any signal of damage, or oil
leakage, he cus omer inspec or or he
service agen in charge of receip shall
make a wri en remark on shipmen
documen s. The receip con rol, mainly
for he porcelain insula ors and he
secondary erminal box, shall be done in
he presence of he forwarding agen , if
possible. The remarks regarding he
condi ion of he goods shall clearly s a e
de ails of he damages found a he ime
of recep ion.
In case of damages, he cus omer
inspec or in charge of receip shall no ify
GE and he insurance represen a ive. All
con ac informa ion shall be indica ed on
shipmen insurance documen s. This
declara ion shall be made wi hin
maximum of eigh days af er receip of
he ma erial.
2.3. Unpacking
Ma erial required for unpacking, lif ing
and pu he ransformer in o service:
Q y Descrip ion
2 Crane, munck or hois .
1 Con ac grease ype PENETROX or
equivalen .
1 Graphi e grease MOLYKOTE ype
P37 or equivalen .
4 Slings of 4,5m of leng h (capaci y
10.000 N)
1 Sling of 1,5m of leng h (capaci y
1.000 N), for cases wi h equipmen
packaged a horizon al posi ion only.
Unpacking of he ransformer should be
made wi h care.
Ver ical packaging
1) Remove upper cover.
2) Remove he smaller ex remi ies.
3) Remove he wood blocking pieces.
4) Remove he larger ex remi ies
5) Remove he four screws a he
equipmen fee and, when applicable,
screws ha anchor he modules o he
package
6) Lif each par of he CVT

Instruction Manual
© GE Grid Solutions
Example of wood blocking pieces
NEVER lift a transformer by its
primary terminal. Always lift it by
the four lifting holes on the
bottom tank and as per indicated
in the next pictures.
Horizon al packaging
1) Remove he upper cover.
2) Remove 3 side covers (excep he side
on which he base ank is fixed wi h
screws)
3) Remove he four screws a he
equipmen fee .
4) Remove he green nylon slings
5) Remove he CVT and lif i following
he nex s eps:
- Use wo slings, one a he neck of he
insula or and o her a he lif ing holes of
he base ank.
- Remove he CVT keeping i in horizon al
posi ion
- Gradually pu he CVT in ver ical
posi ion by lif ing he sling placed in he
neck of he insula or. Keep always he
sling in ver ical posi ion. Handle wi h
care in order do no damage he bellow
flange.

Instruction Manual
© GE Grid Solutions
- Af er confirming he CVT is in ver ical
posi ion and suppor ed in he ground,
change he lif sys em by four slings
placed a he four lif ing holes of he
base ank. Use a 1.5m sling o connec
he o her slings a he heigh of he
insula or neck o guaran ee he CVT will
no move horizon ally when lif ing.
CVT handled wi h i s package:
To lif he packaged ransformer wi h
crane or munck follow he marks on he
wood cra e, once i indica es he righ
posi ion for he slings (nylon bel s
reinforced) and avoid blows and
vibra ions. Handle wi h care!
Example of lif ing he CVT on i s packing
 Placing he CVT on he pedes al:
The use of lif ing slings or s eel cables
wi h a chocker ype hi ch arranged o
suppor he upper me al flange is an
effec ive way o lif he upper modules
of he CD.
Avoid sudden CVT movemen s when
lif ing. To avoid CVT ipping, i is
recommended o use a sling passed
around he upper flange of he insula or
and a ached o o her slings (one on
each side - see figure below).
If he CD of he CVT has more han one
sec ion, he op and bo om modules
mus be joined using he supplied
ma erial:
 Eigh or welve se s of bol s, nu s
and washers for each CD.
or OTC having manometer in the
CD:
The display box of he manome er used
in he sec ions of he CD are par ially
filled wi h liquid glycerin in order o
avoid any damage due o impac during
ranspor a ion. The glycerin is no
necessary af er ranspor a ion.
On he op of manome er, here is
rubber cover wi h a small pro rusion. or

Instruction Manual
© GE Grid Solutions
all OTC models, this small protrusion
needs to be cut after the
transportation. or the cases when CD
units are transported at horizontal
position, cut the protrusion only after
putting the CD at vertical position.
Follow he s eps below for moun ing on
he pedes al:
Place he CD op modules wi h heir
namepla es aligned o he main
namepla e, ins alled on he
secondary erminal box cover in he
base ank.
Place each module slowly, one a a
ime, wi h a crane.
Place he bol s in he upper uni
flange holes.
Fas en he bol s wi h an appropria e
orque (3 kgf.m).
Repea he same procedure for all
subsequen upper modules.
ATTENTION! I is manda ory for he
serial numbers of he CD modules o
ma ch he serial number shown on he
CVT main namepla e. Accuracy and
ferroresonance performance will be
affec ed if incorrec capaci ive modules
are assembled oge her.
The serial reac ance and ransformer
ra io are adjus ed and uned during he
fac ory rou ine es s o mee he
specified accuracy class. Each EMU is
uned o a CD. In his way, it is not
allowed o exchange any CD module or
even a comple e CD from one EMU o
ano her.
Example of lif ing
The base uni (or uni wi h only 1 module)
mus be handled using he 04 lif ing holes
available in he base ank. The use of the 04
lifting holes is mandatory.
4 lif ing eyes