Current transformers for measuring type CTH.xxx.xxx.xxx are transition type transformers, dry, cast in resin, having the role of both electrical insulation and to ensure mechanical resistance. They are intended for indoor use, for measurement and protection, in cells and substations of medium voltage, for insulation levels from 0.72 kV, the corresponding insulation level for medium voltage being provided by the cables used.
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.
The maximum number of secondary windings is 3, depending on the accuracy class, power and the primary 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.
Connections to the secondary windings are made using connection clamps.
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. The transformers are fixed with the help of four screws in the holes provided in their plastic housing.
The transformers are delivered with all the screws and accessories necessary for the connection in the circuit
Transformers are designed, made and tested according to standards IEC 61869-1, IEC 61869-2.
For parameters that are not specified in this documentation, we expect you to contact us by e-mail or telephone.