Current Transformers ТРГ-UEТМ®-330

Current transformers TRG-UEТМ^®-330

Transformers are intended for operation in open and closed switchgears in the temperature range from + 55 ° С to minus 60 ° С non-explosive environment, not containing aggressive gases and vapors in concentrations that destroy metals and insulation. 

• High precision winding class for measurement - up to the commercial electricity metering class 0,2S
• Ability to change the transformation ratio. in operation, the transformation ratio can be changed in a ratio of 1: 2: 4.
• Lack of internal solid insulation eliminates the occurrence of partial discharges, allows not to conduct periodic inspections and tests of insulation, and also minimizes the likelihood of internal breakdown of insulation
• The ability to seal the findings of the secondary winding for commercial metering of electricity, which helps prevent unauthorized access to these findings

General specifications

¹⁾ When the current transformer is turned on for the minimum transformation ratio, the largest peak of the short-circuit current is 80 kA, one-second thermal resistance current is 31.5 kA.

²⁾ A mixture of SF6 (SF6) and CF4 (tetrafluoromethane-14) or SF6 (SF6) and N2 (nitrogen).

The current transformer of the TRG series is a structure, in the upper part of which there is a metal case fixed on the supporting insulator. The insulator, in turn, is fixed on the base in which the terminal box of the secondary windings is located. The primary winding and its terminals are fixed in the metal case, the secondary windings are placed inside the case. The internal cavities of the housing and the insulator are filled with insulating gas.

The design of the primary winding allows obtaining different transformation ratios when changing the number of turns by a series-parallel connection of sections of the primary winding. It is possible to manufacture current transformers without switching with one transformation ratio.

The secondary windings are placed in electrostatic screens, in order to level the internal electric field.

The magnetic core of the secondary winding for measurement is made of nanocrystalline alloy, the magnetic core of the secondary winding for protection is made of cold-rolled anisotropic electrical steel.

The gas pressure is controlled using a density detector with temperature compensation. Density detector is equipped with two pairs of contacts, which allows receiving a signal at two gas density (pressure) values and remotely monitoring gas pressure.

If necessary, there is the possibility of sealing the findings of the secondary winding for electricity metering. Sealing is carried out in any convenient way. For this purpose, special places are provided in the design of the transformer. A protective device is located in the upper part of the current transformer, which connects the internal gas volume with the atmosphere when the internal pressure is significantly exceeded (for example, with excessive gas or internal arc overlapping), which makes the device explosion-proof.

Metrological parameters of secondary windings