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C U R R E N T T R A N S F O R M E R S E L K- C T 0 I N S T R U C T I O N S F O R I N S TA L L AT I O N , U S E A N D M A I N T E N A N C E
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02 Example of outlets
designation
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3. Instructions for installation
General informations
Instrument transformer is electrical equipment
and the electrical installation of the instrument
transformer can be done by skilled personnel
only. The level of experience, age and eligibility
criteria for persons working with, on or near elec-
tric installations is governed by national legisla-
tion. If no asuch eligibility legislation is available
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.
3. Always connect 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 that is not currently in use, to
prevent secondary voltages, which may be haz-
ardous to personnel or damaging to the trans-
former's secondary. The secondary like this
must be additionally grounded.
Mounting
Transformers ELK-CT0 are designed as low-volt-
age current transformers 0.72/3kV, without built
in primary conductor. Primary conductor is not in-
cluded in supply.
Transformers ELK-CT0 are designed for mounting
in gas-insulated switchgears type ELK-04. De-
pending on the protection concept they can be
parameters of 1st core
parameters of 2nd core
parameters of 2nd core
parameters of 3rd core
parameters of 3rd core
additional specification if required
order number
PTB marking (if required)
length of sec. outlets (if required)
arranged in front or behind of the circuit break-
er's interrupting unit. The primary sided insula-
tion is provided by SF
-gas. Up to a rated nominal
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current of 3 150 A current transformers are usu-
ally integrated into the flanges of the circuit
breaker enclosure. Note, in case of a rated nomi-
nal current of 4 000 A a separate current trans-
former is required. All current transformers are
casted on a support which is required to fix the
current transformer in the enclosure. By that, the
distance to the high voltage loaded conductors is
guaranteed even in the case of a short circuit (and
consequently high magnetic forces). The termi-
nals of the secondary windings are interfaced to
the substation via a terminal box consisting of a
multiple bushing disk and terminal blocks. Before
installation of transformer into enclosure all sur-
faces have to be cleaned from dust, grease and
other impurities, see 5. maintenance instructions.
Connection of transformer primary side
The ELK-CT0 transformers don´t have their own
primary conductor. If ELK-CT0 transformers will
be used in other applications than ABB ELK-04
Gas-Insulated Switchgear please contact us for
support.
Connection of transformer secondary side
The transformers ELK-CT0 contains outlet cable
with defined length for each type. Outlet cables
are ended with cable lugs M6. If not specified oth-
erwise in the order, the cable cross-section may
not exceed 6 mm
. The interface of the current
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transformer to the terminal box is handled with
stranded wire connected to gas-to-air bushings
with 60 pins (M6x12/15) to the outer environ-
ment. Depending on the number of wires either
one or two gas-to-air bushings are available. The
ends of the windings of all cores are correspond-
ingly identified.This identification may be
changed by customer after agreement with man-
ufacturer.
Outlets designation
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02
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