3
—
Instructions for installation, use and
maintenance for current instrument
transformers
1. Service conditions
The transformers need to be installed in indoor
conditions where the ambient air is not signifi-
cantly polluted by dust, smoke, corrosive gases,
vapor or salts.
The transformers are designed for standard ambi-
ent temperatures between -20°C and +105°C and
altitudes below 1 000 m above sea level. The trans-
formers 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 parameters 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
rating plate data.
Dimensional drawing of AT transformer is shown
in Appendix 1. Dimensions of the transformer
may vary and depend on required parameters and
the application they are intended for. This is why
the customer is required to specify the highest or
lowest dimensions, in line with the dimensional
drawing in Appendix 1.
Where:
1)
type code of transformer
2)
corresponding standard
3)
rated short-time thermal current
4)
rated dynamic current
5)
rated frequency
6)
terminal marking for tap of transformer
7)
rated transformer ratio
8)
extended current
9)
rated output (burden)
10)
accuracy classes
11)
year of manufacture
12)
serial number
Label abbreviation definitions
3. Instruction for installation
General information
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 con-
nected to.
Don´t touch incoming connectors and
terminals, or any other parts of the
transformer, except you know for sure
these are earthed.
—
01
—
01 Example of rating
plate
These installation, use and maintenance instructions apply for current instrument
transformers intended for outdoor operation. The instructions refer to current
instrument transformers of the following types:
AT41 – up to 10 000 A; up to 1.2/6/- kV 40 kA(1s) and 100 kA
AT35 – up to 5 000 A; up to 1.2/6/- kV 100 kA(1s) and 120 kA
AT38 – up to 5 000 A; up to 1.2/6/- kV 100 kA(1s) and 120 kA
CURRENT TRANSFORMER
Type: AT41-1055/670
1
IEC 60044-1
2
1,2/6/- kV
Ith:30(1s) kA
3
Idyn:75 kA
4
50 Hz
5
2014
11
Serial:1VLTS114000007
12
1S1-1S2
6
3 000/1A
7
ext.120%
8
3 VA
9
cl.TPY
10
Rb=3 Ohm, Kssc=10, Tp=100 ms
C-O-C-O t´-t´ al-tfr-t´´-t´´al=100-60-500-100-60 ms
Rct=10 Ohm, Ts=1,00 s, Ktd=27,2
