GE KOTEF 72.5 User manual

© GE Grid Solutions
INSTRUCTION MANUAL - MIITR102
COMBINED INSTRUMENT TRANSFORMER
KOTEF 72.5...245

Instruction Manual
© GE Grid Solutions 2
GE Grid Solutions
Av. Nossa Senhora da Piedade, 1021
37504-358, Itajubá - MG –Brasil
AIB
00
07/28/21
FML
FES
Owner
revision
Date
Prepared
Approved

Instruction Manual
© GE Grid Solutions 3
Warning!
Any person involved with transport, installation, energizing, operation and maintenance of
Combined Instrument Transformer (CIT) type KOTEF must read these instructions prior to any
action related to these instrument transformers.
These CITs are built under strict conditions which guarantee the Highest Quality achievement. In
order to keep this high-quality during CIT’s lifespan, it is utmost important that the instructions
in this Manual be thoroughly read and complied with.
THESE COMBINED INSTRUMENT TRANSFORMERS CAN NOT BE STORED IN A
HORIZONTAL POSITION FOR MORE THAN FOUR MONTHS. IF THE TIME OF
TRANSPORTION AND STORAGE EXCEEDS THIS PERIOD, IT IS MANDATORY TO UNPACK
AND PUT THE TRANSFORMER INTO A VERTICAL POSITION, FIXING ITS BASE TO THE
GROUND AND REMOVING THE BELLOWS BLOCKING SYSTEM (PLEASE REFER TO ITEM 4).
****WARNING****
DE-ENERGIZED HIGH VOLTAGE EQUIPMENT MAY CONTAIN TRAPPED CHARGES
Read this instruction book before installation and operation of the unit.
Never work on High voltage equipment without first having short-circuited and grounded all terminals and
metallic housings as the inherent capacitance may have electric charges with voltage at the lethal level. In
addition, a ground rod should stay on the line terminal as long as people work on the unit.
In the event an electrical test is to be performed, the person supervises the test will be held responsible for
performing the test in a safe manner under the local / federal regulation. After the test, the ground rod should be
put back to the line terminal until the unit is ready to be energized.
Note: To effectively discharge High voltage equipment do the following:
a) Put the ground rod onto the line terminal (Such action will short-circuit the entire unit and put the line terminal to
the ground potential), and
b) Use another ground rod to attach to any intermediate metallic housing for duration of 10 –15 seconds to be certain
that there is no residual electrical charge within the unit.
Preliminary Remarks
During reception of the CITs, it is important to check unpacking attentively in order to control the
condition of the transportation crate and the transformer itself. Any irregularities shall be
recorded on the transport delivery note and a formal communication shall be sent to the
responsible person immediately.
The supplied insulator can be made of porcelain, therefore, sudden movements that can cause
damage due to cracks shall be avoided.

Instruction Manual
© GE Grid Solutions 4
INDEX
1. GENERAL DRAWING .....................................................................................................................................................................5
2. DESIGN AND CONSTRUCTION .................................................................................................................................................6
2.1. Construction and primary circuit..................................................................................................................................6
2.2. Secondary circuit..................................................................................................................................................................6
2.3. Paper-oil insulation .............................................................................................................................................................6
2.4. Oil volume compensation system................................................................................................................................6
2.6. Cast aluminum tank............................................................................................................................................................7
2.7. External metallic parts.......................................................................................................................................................7
3. TRANSPORT, RECEPTION, UNPACKING AND STORAGE ..............................................................................................7
3.1. Transportation.......................................................................................................................................................................7
3.2. Reception .................................................................................................................................................................................7
3.3. Unpacking...........................................................................................................................................................................................8
3.4. Storage ......................................................................................................................................................................................9
4. BELLOWS BLOCKING SYSTEM AND ASSEMBLY IN THE STRUCTURE....................................................................9
4.1. Bellows blocking system...................................................................................................................................................9
4.2. Assembly in the structure............................................................................................................................................. 10
5. CONTACT SURFACES PREPARATION................................................................................................................................. 10
6. CONNECTIONS.............................................................................................................................................................................. 10
6.1. Primary Terminals............................................................................................................................................................. 10
6.2. Primary bar type (if applicable)................................................................................................................................... 10
6.3. Double / Triple Reconnection Primary type (if applicable) ............................................................................ 10
6.4. Secondary terminals/Neutral Terminal .................................................................................................................. 11
6.5. Terminal marking............................................................................................................................................................... 11
7. OIL LEVEL INDICATOR ............................................................................................................................................................... 11
8. INSPECTION BEFORE FIRST ENERGIZING ........................................................................................................................ 11
9. MAINTAINENCE AFTER ENERGIZING ................................................................................................................................. 12
10. PROPER DISPOSAL OF TRANSFORMERS COMPONENTS AFTER LIFESPAN .................................................... 13

Instruction Manual
© GE Grid Solutions 5
1. GENERAL DRAWING
Description and characteristics of the KOTEF Combined Instrument Transformers. For more
details, please refer to the picture below.
1. Top Cover
2. Oil Level Indicator (metallic bellows)
3. Primary Reconnection Terminals
4. Primary terminals: aluminum or copper
5. CT Headhousing (current transformer part)
6. Porcelain or composite insulator
7. Terminal box of secondary windings and cover
8. VT Tank (voltage transformer part)
9. Fixation Base
General Drawing of KOTEF
1
2
3
4
5
6
7
8
7
9
7

Instruction Manual
© GE Grid Solutions 6
2. DESIGN AND CONSTRUCTION
2.1. Construction and primary circuit
The active part of the voltage
transformer is located below the
porcelain insulator and the current
transformer part above. The primary
circuit is short, rigid and straight,
minimizing heating. In addition, it
withstands electrodynamics forces
more easily, allowing high level
performance, related to
electrodynamics and thermal effects, in
a presence of short-circuit currents.
Primary series and parallel connections
with external links (for reconnection 1:2
or 1:2:4) or, if necessary, n-turn (more
than 4 turns) designs can be provided.
This arrangement allows also better
accuracy in transient conditions.
The primary terminals are directly
connected to the conductor.
Attention! Do not lift the unit at the
primary terminals or remove the
primary terminals!
2.2. Secondary circuit
Related to the CT’s active part, the
toroidal ferromagnetic cores are
manufactured either from very high
permeability grain-oriented steel or
from specialized alloys. In order to
achieve a satisfactory transient
behavior, protection cores can also be
provided with gaps.
All secondary windings are enclosed in
an aluminum box which protects them
against high frequency disturbances
while acting as a low voltage shielding
electrode. This aluminum box is
extended up to the base by an aluminum
tube which contains all secondary leads.
The cross section of the earth
connections is designed to support fault
currents.
The bottom of the hermetic and
watertight secondary terminal box is
closed by a fitted plate, with or without
cable gland depending on customer
requirements.
2.3. Paper-oil insulation
The active part of the transformer is
insulated by a vacuum impregnated
oil/paper system. Degassed and filtered
mineral oil is used and is heated before
filling to provide maximum
impregnation. It is an insulating oil with
excellent aging stability and gas
absorbing properties. It does not
contain any Polychlorinated Biphenyl
(PCB).
2.4. Oil volume compensation system
To protect the oil from the environment,
the CT head is sealed by a metallic
bellows. The bellows assembly provides
pressure compensation for temperature
variation and allows the transformer to
work virtually free of over-pressure.
The bellows resists aging and corrosion.
IF THE HERMETIC SEAL OTHER THAN
DURING OIL SAMPLING IS BROKEN,
CONTACT THE MANUFACTURER
IMMEDIATELY.
An oil level indicator is provided and is
scaled to show the oil level over the

Instruction Manual
© GE Grid Solutions 7
operating range. It is visible from ground
level behind a Plexiglas window in the
top cover. The limit positions are marked
by red stripes at the top and bottom.
Please refer to item 7 for more
information.
2.5.
2.6. Cast aluminum tank
The base tank is made of corrosion-
proof aluminum. The core housing (CT-
part) has up to 7 independent toroidal
cores enclosed in a thick-walled
aluminum alloy core housing and is
connected to the base through a stem
and a ground fault current carrying
connection. Attached to it are a large
terminal box, ground pad and oil
sampling valve. For the location of the
secondary terminals and the neutral end
of the HV winding of the VT part (for
example H2, N…).
2.7. External metallic parts
The external metallic parts do not
require maintenance and they are
protected against corrosion effects.
3. TRANSPORT, RECEPTION,
UNPACKING AND STORAGE
3.1. Transportation
Transformers are shipped in horizontal
position with the feet mounted to the
crate/skid and the head resting on
damping foam. For overseas shipment,
the CIT is packed in wooden crates
designed according to SEI (cat. 4)
specification. The crates can be stacked,
but no more than one crate stacked
over.
3.2. Reception
Whether the shipment is of
manufacturer’s or customer’s
responsibility, the customer inspector or
the service agent must check the
following on receipt of delivery:
If the crates show any signs of impact,
blows or fractures, or if the transformers
have any sign of damage or oil leakage,
the customer inspector or the service
agent in charge of receipt shall make a
written remark on shipment documents.
The receipt control, mainly for the
insulators and the secondary terminal
box, shall be done in the presence of the
forwarding agent, if possible. The
remarks regarding the condition of the
goods shall clearly state details of the
damages found at the time of reception.
In case of damages, the customer
inspector in charge of receipt shall notify
GE and the insurance representative. All
contact information is indicated on
shipment insurance documents. This
declaration shall be made within eight
days after receipt of the material.

Instruction Manual
© GE Grid Solutions 8
3.3. Unpacking
Material required for unpacking and
lifting the transformer up to vertical
position:
Qty
Description
1
Crane, munck or hoist
1
Swing-bar of 0.7 to 0.9m of length
with 2 holes
4
Shackles of 18mm (3/4”)
diameter
1
Graphite grease MOLYKOTE type
P37 or equivalent.
2
Slings with proper length to
execute the lifting operation
safely
Unpacking the transformer shall be
made with caution:
1) Remove the smaller extremities;
2) Remove the upper cover;
3) Remove the larger extremities.
Attention!
NEVER lift a transformer by its
primary terminals. Lift it by the
lifting eyes on the transformer top.
All four lifting eyes must be used
during lifting operation.
To lift the transformer with crane or
munck, follow the marks on the wooden
crate, once they indicate the right
position for the slings (nylon belts
reinforced) and avoids blows and
vibrations.
Follow the instructions shown in the
following drawings for lifting the unit. All
cables or slings shall be kept in vertical
position during the lifting. It is
recommended to lift the transformer
slowly.
Max. 50mm
Safety tether
During handling,
the cables must
be kept in vertical
position.
Synthetic foam cushion to absorb
impact
Support

Instruction Manual
© GE Grid Solutions 9
Once the transformer is in the vertical
position, it should be moved and
mounted according to the latter figure.
Be careful not to tilt the unit such that
the center of gravity moves beyond any
of the four (4) matched slings. Use a
safety tether. Refer to the nameplate for
weight
3.4. Storage
The units can be stored:
▪no more than four months after the
CITs left the factory,
▪in the horizontal position,
▪on a smooth surface and
▪within minimum and maximum
ambient temperature as per CIT
specification.
▪more than four months after the CITs
left the factory,
▪on a smooth surface,
▪unpacked,
▪put in vertical position and
▪after removal the bellows
blocking device as described in
item 4.
NOTE: The units stored outdoors in
vertical position must be screwed on to
the ground, even if the storage is
foreseen for a short period of time.
4. BELLOWS BLOCKING SYSTEM AND
ASSEMBLY IN THE STRUCTURE
4.1. Bellows blocking system
For transportation purposes, the
metallic bellows device is blocked
(secured from movement) using
cushions of synthetic foam slightly
compressed by the top cover. A
protection of plastic film is also put in
place around the bellows to protect it
against contact with the top cover.
In order to remove the blocking system,
place the transformer in vertical position
on a flat surface.
Remove the bellows blocking device,
following the procedure below:
1) Mark the position of the top cover
with respect to the head of the
transformer with a vertical line
(using a marker, chalk or pencil);
2) Remove the screws that fix the top
cover;
3) Remove the bellows blocking device
and the protection film;
4) Confirm by visual check that the
bellows device is in good condition:
a) Geometry: Top of the bellows is
horizontal (i.e., not tilted due to
possible deformation of the
bellows convolutions). No
distortion and/or asymmetry of
the bellows (i.e., convolutions are
evenly displaced around the
circumference of the bellows)
b) Surface: no damage or
deformation such as dents
and/or buckling in the bellows
TO AVOID DAMAGE TO THE BELLOWS
DEVICE, NEVER SUPPORT ANY MATERIAL
ON THE BELLOWS.
5) Reinstall the Top Cover with care
lining up the vertical marker line with
the head of the transformer to
ensure that original fixing position is
maintained. Confirm that the
bellows is free for internal
movement and in a vertical position.

Instruction Manual
© GE Grid Solutions 10
The green oil level marker shall be
clearly visible through the window.
6) Tighten the fixing screws. The
threads shall be lubricated with
grease << MOLYKOTE P37>> or
equivalent. The screws shall be
tightened to a maximum torque of
7N.m for screw M6 and 16N.m for
screw M8.
4.2. Assembly in the structure
The transformer shall be set up in
vertical position.
It is very important that the surface on
which the CIT will be set up is flat
(tolerance for no more than 1mm).
Verify if the four feet are supported on
the structure. If not, it is necessary to
insert a shim before putting the fixation
screws.
Remove the lower lid of black plastic, if
applicable, from secondary terminal box.
It is only used for transport. It cannot be
used as tube guide.
5. CONTACT SURFACES PREPARATION
It is recommended to clean all aluminum
contact surfaces with sandpaper 150
grain in order to eliminate the oxidation
layer. Scrub the contact surfaces with a
metallic brush (diameter of the thread
0.3mm) and impregnate with grease of
the type “PENETROX” or equivalent. All
the surfaces must be completely
covered with grease.
For plated contacts, only clean (do not
use sandpaper) and polish the side of
the aluminum. Cleaning plated surfaces
with sandpaper could cause damage to
the protection coat.
6. CONNECTIONS
6.1. Primary Terminals
Connect the high voltage cable, or tube,
to the primary terminals with
appropriate connectors so that they
assure a good contact.
6.2. Primary bar type (if applicable)
Primary bar is always supplied
completely assembled with the
delivered transformer. Clean the
primary terminal as explained in item 4).
6.3. Double / Triple Reconnection
Primary type (if applicable)
The current ratio of the CIT can be single
with only one single bar, double or triple
primary ratio. Double or triple primary
ratio can be easily changed by the user
Top Cover
Cushions of
synthetic
foam
Protection
film
Bellows
Fix screw

Instruction Manual
© GE Grid Solutions 11
following the instruction of the approved
set of drawing. This changing ratio is
made by means of reconnection bars
located in the headhousing, closer to
primary terminals. Please refer to the set
of drawing to know how the
reconnection bars need to be positioned
in order to have the required ratio.
6.4. Secondary terminals/Neutral
Terminal
The unit is shipped with the current
transformer secondary short circuited
and connected to the secondary box
ground, the voltage transformer part is
open circuited and not grounded.
Attention!
Do not leave any secondary windings
of the current transformer part open
- High Voltage!
Do not short-circuit the secondary
winding of the voltage transformer
part! The neutral terminal of the
voltage transformer part must be
connected to ground prior to and
during operation!
6.5. Terminal marking
Primary and secondary terminal marking
are done according to the specified
standard. please refer to the set of
drawing.
Primary and secondary connection
scheme are shown on schematic plates.
7. OIL LEVEL INDICATOR
The position of the oil indicator can be
verified through the rectangular window
of the top cover.
The plate of the indicator is divided in
three areas. Central area shows the
green strip and higher and lower areas
are shown with a red strip. In normal
conditions, the indicator shows the
green strip of the indicator.
In case of oil level indicator is in either of
the red areas, the transformer must be
removed from operation and GE
informed immediately.
8. INSPECTION BEFORE FIRST
ENERGIZING
After putting the CITs in vertical
position, it is necessary to wait at
least 48 hours before energizing it!
Verify terminals connections to
assure the correct tightening torque.
Make sure that the neutral terminal
of the voltage transformer part (H2,
N …) is connected to ground. Confirm
all intended groundings.

Instruction Manual
© GE Grid Solutions 12
Confirm that the secondary circuit of
the voltage transformer part is not
shorted.
Make sure that no secondary winding
of the current transformer part is
open circuited.
Verify the correct position of the
primary terminal (transformer with
reconnection primary bars). Refer to
the set of drawing.
Verify that the oil level indicator is in
the green strip area.
Whilst all care is taken in the factory
during oil filling, the surface near of
screws and bellows could have a small
quantity of oil. This shall not be
considered as an oil leakage provided
the bellows are positioned within the
green strip area.
It is not necessary to remove oil
samples for analysis. The CIT is
hermetically sealed
If required, small quantity of oil can be
taken. Always verify oil level indicator
before take oil samples.
Never complete oil volume without
prior formal authorization of GE.
Important remark:
During commissioning, it is
recommended to register the values
acquired for each of the performed tests
in order to compare with future
measurements during the CIT’s lifetime.
The measurements taken in the factory
are important as so the measurements
during commissioning of each
transformer. The comparison between
test results measured at the field allows
following the evolution of each
parameter.
9. MAINTAINENCE AFTER ENERGIZING
Besides regular cleaning of the
transformer surface and especially the
insulator, no routine maintenance is
required on the transformers. However,
the oil level indicator position should be
checked regularly, along with visual
inspections during the normal
scheduled maintenance periods. It is
good practice to compare the oil level
indicator position of neighboring units.
Also, the inside of the terminal box and
the ventilation screens should be
checked for cleanliness.
After installation and energizing, the
transformers shall not require any
further intervention. However, it is
suggested performing visual inspections
during the first weeks of service in order
to:
Verify if there is no oil leakage near the
fixation base and secondary terminal
box.
With an infrared imaging device, check if
the primary terminal connections are
not overheating. Compare with other
CITs in the same circuit.
After one year of operation, it is advised
a detailed inspection of tightening
torques and oil leakage and thereafter
twice per year according to the
substation maintenance contract.

Instruction Manual
© GE Grid Solutions 13
If possible, GE suggests disconnecting
the equipment to perform the following
examinations:
1) Insulator: Depending on the
pollution level, it is necessary to
clean the porcelain;
2) Metallic components: check for
corrosion;
3) Tightening torque of primary and
secondary connections. Any
adjustments shall be conducted as
described in the item “Primary
Terminals” of this document;
4) Secondary terminal box: If necessary
clean inside the terminal box.
5) Verify oil level indicator and if there
is any signal of oil leakage;
6) Remove the top cover to have access
to the bellows and verify if there is
any signal of oil leakage near the
fixation of the bellows and / or if the
bellows is in good condition.
Tests
It is recommended after the first few
hours of operation and whenever there
is a change in the primary current (in the
bar connection), performing the
measurement of the primary terminal
temperature with a proper temperature
measuring instrument.
It is advised to perform the following
tests before putting the equipment in
operation and thereafter at four-year
intervals depending on availability of
the:
1) Ratio (TTR);
2) Polarity (Polarity meter);
3) Saturation Voltage (ac voltage
source, Voltmeter and Ammeter);
4) Ohm Resistance (Wheatstone
bridge);
5) Insulation Resistance with any
megohmmeter;
6) Tan δof the HV insulation (Double
M4100, Omicron CPC100 or any
equivalent).
Important remark:
During commissioning and tests, it is
recommended recording the results
acquired in the tests abovementioned.
In case of doubts, please contact the
technical assistance support of GE: +55
35 3629 7042 or 7038 or 7000
10. PROPER DISPOSAL OF
TRANSFORMERS COMPONENTS
AFTER LIFESPAN
The instrument transformers are mainly
composed of the following components,
which after transformer’s lifespans
require a properly disposal in order to
prevent environmental contamination.
Components
Recommended
Disposal
Metallic materials
Metal recycling
company
Resin and
materials
saturated with
resin
Oil disposing
company properly
licensed to perform
such activity
Oil (PCB-free) –
classified as Class I
hazardous residue
Oil disposing
company properly
licensed to perform
such activity
Material
contaminated with
oil
Co-processing or
incineration at a
company properly
licensed
Porcelain insulator
Industrial landfill
properly licensed

Instruction Manual
© GE Grid Solutions 14
Composite
insulator
Industrial landfill
properly licensed
Other materials
Industrial landfill
properly licensed
The disposal of oil and components
contaminated with oil directly into the soil
or water is prohibited.
For further information or clarifications,
contact GE environment department: +55
35 36297112.