ABB KOKM Series Parts list manual

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MEDIUM VOLTAGE PRODUCT
KOKM Cable current instrument
transformers
Instruction for Installation, use and
maintenance

2KOKM CABLE CURRENT INSTRUMENT TRANSFORMERS
INSTRUCTION FOR INSTALLATION, USE AND MAINTENANCE
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Scope of Contents
3 1. Service conditions
3 2. Technical details
4 3. Instructions for installation
4 General information
4 Safety instructions
4 Mounting
5 Connection of the transformer
primary side
5 Connection of the transformer
secondary side
5 4. Instructions for use
5 Routine test report
6 5. Instructions for maintanence
6 6. Transport & Storage
6 7. Disposal
6 8. Handling
6 9. Normative references
7 Appendix 1. Examples of
electrical wiring / secondary
marking

3
1. Service conditions
The transformers need to be installed in dry and in-
door conditions where the ambient air is not sig-
nificantly polluted by dust, smoke, corrosive gases,
vapours or salts. The transformers are designed
for standard ambient temperatures between -25°C
and +40°C (it depends on each type) and altitudes
below 1 000 m above sea level. The transformers
can also be operated at higher or lower ambient air
temperatures and higher installation altitudes if
such are agreed with the manufacturer.
2. Technical details
Technical details and specifications of each of the
transformers are shown on a rating plate fixed to
the transformer body. It is not allowed to operate
the transformer at values exceeding the name-
plate data. Dimensional drawings of KOKM trans-
formers are defined in the Catalogue. Dimensions
of the KOKM transformers are defined by the type
marking, see the example:
KOKM 1 D C 10
Transformers width
10 = 100 mm (possibility -
6, 8, 10, 12, 14, 16, 18, 20,
22, 24,...30)
Outer diameter
C = 148 mm
Hole diameter
D = 60 mm
Rate voltage 1 = 1.2 V
Type KOKM - indoor use
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01
Where:
 serial number
 type code of transformer
 rated frequency
 terminal marking
 rated transformer ratio
 ratio extension
 rated output (burden)
 accuracy class
 
power-frequency withstand voltage
 rated short-time thermal current
and duration
 corresponding standard (standards)
 rated dynamic current
 metrological standard
 year of manufacture
EInsulating temperature class
 Ambient temperature
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01 Example of cable
current instrument
transformer rating plate
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Instuctions for installation, use and
maintenance for cable current instrument
transformers
These instructions apply for cable current instrument transformers intented for
indoor operation, where primary insulation is provided by primary conductor and its
insulation. KOKM transformers are designed for Usys > 1 kV.
The instructions refer to the following types: KOKM 06, KOKM 072, KOKM 1

4
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0
KOKM CABLE CURRENT INSTRUMENT TRANSFORMERS
INSTRUCTION FOR INSTALLATION, USE AND MAINTENANCE
3. Instructions for installation
General informations
Instrument transformer is an electrical equip-
ment and the electrical installation of the instru-
ment transformer can be done by skilled person-
nel only. The level of experience, age and
eligibility criteria for persons working with, on or
near electric installations is governed by national
legislation. If no such eligibility legislation is avail-
able the corresponding requirements can be
found in EN 50110-1 standard.
Safety instructions
1. Always consider the transformer as a part of
electric circuit which it is connected to. Don´t
touch incoming connectors and terminals, or
any other parts of the transformer, except you
know for sure these are earthed.
2. Ground always the metallic base of the instru-
ment transformer, if exist.
3. Connect always one terminal of each secondary
winding of the transformer to the earth. When
the secondary of transformer is intercon-
nected, there should be only one grounded
point to prevent accidental paralleling with sys-
tem grounding wire.
4. Always short-circuit the secondary of the cur-
rent transformer, which is not currently in use,
to prevent secondary voltages, which may be

transformer’s secondary. The secondary like
this must be additionally grounded.
Mounting
The KOKM type transformers are designed for


conductor. Their use at higher voltage levels
needs always the transformers to have combined
with primary conductor provided with its own in-
sulation. The primary conductor is not a part of
transformer delivery. Therefore, the KOKM trans-
formers are mounted and placed at the option of
the customer, based on the application chosen
and the insulated conductor used on the primary
side. Types of the transformer fixation are visible
on Fig. 2 – Fig. 5.
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02 Window type 4 holes:
Fixation is done by 4
straight-through holes
with 15 mm diameter.
Screws for fixation are
not part of delivery. For
exact dimension see the
catalogue for specific
type. Connection of
transformer primary
side.
—
03 Window type 2 holes:
Fixation is done by 2
straight-through holes
with 12 mm diameter.
Screws for fixation are
not part of delivery. For
exact dimension see the
catalogue for specific
type.
—
04 Ring core type, with
base: Fixation is done by
2 or 4 holes in the base
of transformer. Screws
for fixation are not part
of delivery. For exact
dimension see the cata-
logue for specific type.
—
05 Ring core type,
without base : Fixation
is done by 4 nuts casted
in the transformer.
Screws for fixation are
not part of delivery. For
exact dimension see the
catalogue for specific
type.
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02
—
03
—
04
—
05

5
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0Connection of transformer primary side
The KOKM transformers don´t have their own pri-
mary conductor. The primary conductor is de-
signed as a bushing with its own insulation, or in-
sulated cable.
Connection of transformer secondary side
The KOKM transformers have two types of sec-
ondary connection according to design.
1) Cables
Length and type of the cable is variable according
to the types (see catalogue)
All cable outlets has marking according to the
connection
2) Secondary terminal
Screw the secondary terminal connection by M5
screw with highest torque 3.5 Nm and lowest
torque 2.8 Nm. Maximum permissible tightening
torque for M3 screws securing plastic terminal
cover is 0.5 Nm.
Maximal diameter of cable or conductor con-
nected to one secondary terminal: 2x2.5 mm.
There is alowed to use only the screwes delivered
with transformer into secondary terminals. In
case of any need to use different screw be sure
that the thread hole and diameter is correct for
non original screw. Othervise there is high risk of
damage of the terminal.

connection is done by terminal block VTRK 4 GY
equipped with M3 screws with highest torque 0.8
Nm and lowest torque 0.6 Nm.
Maximal crosssections of secodnary cables are 4
mm2(strand) or 6 mm2(solid conductor).
4. Instructions for use
Current instrument transformers are used:
• to convert large currents in the primary circuit
to an appropriate level for secondary circuit
equipment (relays and meters);
• to insulate primary and secondary circuit from
each other to protect the secondary equipment
from the harmful effects of large current ap-
pearing during the operation (short circuits).
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06 Example of
application
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06
Example of secondary terminal
connection realized by screws
with cover
Example of secondary terminal
connection realized by screws
without cover
Example of secondary terminal
connection realized by terminal
block with cover
Example of secondary terminal
connection realized by terminal
block without cover

6KOKM CABLE CURRENT INSTRUMENT TRANSFORMERS
INSTRUCTION FOR INSTALLATION, USE AND MAINTENANCE
The use of current transformer for other purpose
then described above is forbidden if not agreed
with the producer.
Routine test report
The routine test report of a current instrument
transformer includes:
a) verification of terminal markings;
b) inter-turn overvoltage test;
c) determination of errors.
On customer request the following information
can be provided free of charge:
• -
placement values;
• 
Additional reports for supplementary charge,
made available on request:
• test report on accuracy;
• 
• additional nameplates (if more than 2 are re-
quired);
verification tests for measuring cores (classes
0.2; 0.2 S; 0.5; 0.5 S).
5. Instructions for maintenance
Excessive dust sediments or any other type of
contamination must be removed from the trans-
former by a soft brush, in a way not to damage
the insulation or cables taken out from the trans-
former.
6. Transport & Storage
Permitted temperature for transport and storage
ranges from -40°C to +70°C. During transport and
storage the transformers have to be protected
from direct impact of solar radiation. The trans-
formers are delivered in wooden crates or fixed
on transport pallets.
7. Disposal
Materials used in instrument transformers are
considered as materials without environmental
impact and materials are not toxic. Instrument
transformers have to be disposed of in accor-
dance with national legislation relevant to do-
mestic waste disposal.
8. Handling
Most of the KOKM transformers weight less than
25 kg and, consequently, they can be handled
manually. In case of higher weight it is necessary
to use carry belts threaded through the trans-
former internal opening.
ATTENTION: The process of transformer han-
dling has to comply the occupational health and
safety rules. It is forbidden to stay or move be-
low a suspended load. Always make sure the
load is safely tied and secured, what makes its
loosening or turnover impossible. All transform-
ers has to be carried carefully to prevent any
damage to the transformer.
9. Normative references
IEC 61869-1 Current instrument transformers
IEC 60529 Degrees of protection provided by en-
closures
ISO 12100 Machine safety – basic concepts, gen-
eral principles of design
EN 50110-1 Operation of electrical installations
Current instrument transformers are designed,
tested and manufactured in accordance with in-
ternational or national standards, the customer
requirements, based on an agreement between
the customer and the manufacturer. The specific
standard is always mentioned on the transformer
nameplate.
As an example the following standards can be
mentioned:
IEC 60044-1; IEC 60044-6; IEC 61869-1;
IEC 61869-2;
AS 60044-1; AS 1243-1982;


IEEE Std C57.13.6-2005;
ANSI C57.13-1978;
CSA Std CAN3-C13-M83;
GOST 1516.3-96; GOST 7746-2001;

When agreed transformers made in accordance
with other standards can also be supplied, or in
accordance with other release version of the
above standards.

S2S1
P2P1
S3
P1 P2
S1 S2
2S22S1
P1 P2
1S1 1S2
one secondary winding example: 100/1 [A/A]
multi-tap secondary winding example: 50-100/1 [A/A]
two secondary winding example: 800/5/5 [A/A/A]
7
Appendix 1.
Examples of electrical wiring /secondary marking

1VLM000619 Rev.4, en 2019.09.26
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NOTE
We reserve the right to make technical
changes or modify the contents of this docu-
ment without prior notice. With regard to
purchase orders, the agreed particulars shall
prevail. ABB does not accept any responsibil-
ity whatsoever for potential errors or possi-
ble lack of information in this document.
We reserve all rights in this document and in
the subject matter and illustrations con-
tained therein. Any reproduction, disclosure
to third parties or utilization of its contents -
in whole or in parts - is forbidden without
prior written consent of ABB.
Copyright© 2019 ABB
All rights reserved
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