Current instrument transformers CTN24.M type

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Current instrument transformers CTN24.M type

The instrument transformers type CTN24.M, are designed for indoor use in electric distribution panels, for measuring and protection.

They are designed to be resistant up to 24 kV insulation level, molded in epoxy resin under vacuum. The mounting of transformer inside the panel, is realizing through the base metal plate with four screws.

Product available upon customer request

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Current transformers for measuring type CTN24.M are transformers of support type, dry, cast in epoxy resin, under vacuum, having the role of both electrical insulation and to ensure mechanical resistance. These are intended for indoor users, for measurement and protection, in medium voltage cells and substations, for insulation levels from 3.6 / 10/40 kV to 24/50 / 125 kV.

The value of the secondary nominal currents is 5 A or 1 A, there is also the possibility to be combined. The accuracy classes of the measuring secondary can also be 0.2S, 0.2, 0.5S, 0.5, 1, 3, and for the protective secondary they are 5P and 10P. For measuring secondary, the required accuracy class is guaranteed in the range of 25% - 100% of the nominal load, and for protection secondary the accuracy class is guaranteed at 100% of the nominal load.

The working limit current of these transformers is 120% of the rated current. Upon request, the value of this current can be exceeded by an agreement between the manufacturer and the beneficiary, for example 200% of the rated current.

Transformers are designed with the possibility of being reconnected in primary or secondary.

The maximum number of secondary windings is 2, depending on the accuracy class, power and the nominal primary thermal current.

Mandatory, one terminal of each secondary winding must be connected to earth, and unused secondary windings are short-circuited and also connected to ground.

The connections to the secondary windings are made inside a terminal box, provided with a transparent sealable cover and the cable gland, type PG9.

The primary windings of CTN24.M type transformers are built with one or more turns. The primary winding can be simple - with a single transformation ratio or reconnectable - with two transformation ratios. The reconnection in the primary circuit is made with the help of two brass tiles that are mounted with M12 hex head screws. Changing the transformation ratio to this type of transformer is done by moving the tiles from the series connection to the parallel connection.

The secondary windings are made on magnetic cores with oriented grains, made of different alloys, depending on the accuracy class required.

Transformers can be mounted in any position. Fixing the transformers is done with the help of four screws in the holes provided in their motherboard.

The transformers are delivered with all the screws and accessories necessary for the connection in the circuit

The earthing connection will be made with an M5 screw, located in the terminal box of the transformer and connected constructively to its metal flange.

Transformers are designed, made and tested according to standards IEC 61869-1, IEC 61869-2.

Metrological verification bulletins can be issued upon request.

For parameters that are not specified in this documentation, we expect you to contact us by e-mail or telephone.

Highest voltage for equipment: 3.6; 7.2; 12; 17.5; 24 kV
Test with applied voltage 50 Hz - 1 min; 10; 20; 28; 38; 50 kV
Lightning pulse test - 1.2 / 50 µs: 40; 60; 75; 95; 125 kV
Primary rated current - In: 5 ÷ 3200 A
Possibility of reconnection in the mayor: YES
Secondary rated current - Is: 5 and / or 1 A
Possibility of reconnection in secondary: NO
Frequency: 50 Hz
Thermal current - Ith: 0.5 ÷ 100 kA
Dynamic current - Idyn: 2.5 x Ith
Rated thermal current - Icth: 1.2 x In
Secondary winding power: 1 ÷ 30 VA
Accuracy class secondary winding measurement: 0.2S; 0.2; 0.5S; 0.5; 1; 3 %
Security factor - FS: 5; 10; 15
Accuracy class secondary winding protection: 5P; 10P
Accuracy limit factor - ALF: 5; 10; 15
Insulation class: E
Altitude: maximum 1000 m.
Ambient working temperature: - 5… + 40 ° C.
Storage transport temperature: - 25… + 40 ° C.
Force in the console on the primary terminals: 5 kN
Standards: IEC 61869-1: IEC 61869-2

Instructions for connecting circuit current transformers for measurement,

type CTX-1x.xxX

Current transformers for measuring type CTX-1x.xxX, executed and supplied with a primary winding (P1-P2), with barriers (B) or without barriers (N), may have one or more secondary windings (1S1-1S2, 2S1-2S2,…).

Terminals “S2” of all secondary windings, must be connected to ground.

Attention! The product is delivered with secondary windings with shorted start and end terminals.

When only one secondary winding is used, but the second secondary winding is not used in the load, the start and end terminals of the unused secondary winding must be short-circuited and connected to ground. When it is desired to use the secondary in this situation, the starting terminal of the winding must be disconnected from the ground, following the diagram below.

type CTX-2x.xxX

Current transformers for measuring type CTX-2x.xxX, executed and supplied with two reconnectable primary windings (P1-C2; C1-P2), with barriers (B) or without barriers (N), may have one or more secondary windings (1S1-1S2, 2S1-2S2,…) .

The primary windings can be connected as follows:

Series  - connect C1 with C2, for primary current 1 x Ip

Parallel  - connect P1 with C1 and P2 with C2, for primary current 2 x Ip

Terminals “S2” of all secondary windings, must be connected to ground.

Attention! The product is delivered with secondary windings with shorted start and end terminals.

When only one secondary winding is used, but the second secondary winding is not used in the load, the start and end terminals of the unused secondary winding must be short-circuited and connected to ground. When it is desired to use the secondary in this situation, the starting terminal of the winding must be disconnected from the ground, following the diagram below.

type CTX-3x.xxX

Current transformers for measuring type CTX-3x.xxX, executed and supplied with a primary winding (P1-P2), with barriers (B) or without barriers (N), may have one or more reconnectable secondary windings (1S1-1S2-1S3, 2S1-2S2-2S3,…) .

Secondary windings can be connected as follows:

Great report  - 1S1-1S3 is connected and 1S2 remains unconnected for 2 x Ip

Small ratio  - 1S1-1S2 is connected and 1S3 remains unconnected, for 1 x Ip

Terminals “S1” of all secondary windings, must be connected to ground.

Attention! The product is delivered with secondary windings with shorted start and end terminals.

When only one secondary winding is used, but the second secondary winding is not used in the load, the start and end terminals of the unused secondary winding must be short-circuited and connected to ground. When it is desired to use the secondary in this situation, the starting terminal of the winding must be disconnected from the ground, following the diagram below.

Permissible force limit for tightening screws:

M  4 = 0,8 …1,2 Nm

M  5 = 2,8 … 3,5 Nm

M  8 =   16 … 20 Nm

M 12 =  40 … 50 Nm

Instructions for handling, transport, storage and commissioning
a transformatoarelor de curent pentru măsurare, tip CTN24.M

Manipulation:
CTN24.M type transformers are heavy objects in relation to their volume. Therefore, the handling and transport of such products will be done with care, so as not to cause injuries to the body of the maneuverer of any kind. The rules of labor protection regarding the handling of heavy objects will be strictly observed. Direct contact with the ground of the transformers will be avoided, especially in conditions of high humidity.

Transport:
The transport of CTN24.M type transformers will be done in normal atmospheric conditions, avoiding contact with atmospheric precipitation and following the special specifications ("avoid rain", "attention to fragile object", "no overlaying", etc.). marked with a label on the transformer package, where applicable.

Storage conditions:
The storage of CTN24.M type transformers will be done in closed spaces with environments free of humidity, highly corrosive substances, chemically active substances, flammable or explosive vapors and without electrically conductive dusts.

Putting into service:
When commissioning CTN24.M type transformers, it will be considered their location in a space that respects the ambient temperature level in order to be included in the insulation class in which they were made, elements that are specified on the product label.
When commissioning, the corresponding circuit connection must be observed, in accordance with the markings on the transformer terminals and the connection instructions for these types of transformers. Only multi-wire (corded) cables or connecting rods, the section of which corresponds to the rated current specified on the product label, electric slippers of appropriate dimensions, with the insulation distance on the surface between the slippers, etc., shall be used.

ModelIcon2D Drawing3D ModelPDF Drawing
CTN24.M01DXFSTEPPDF
CTN24.M01.BDXFSTEPPDF
CTN24.M01.RDXFSTEPTPDF
CTN24.M01.RBDXFSTEPTPDF