Medium-voltage instrument transformers
Current instrument transformer
CTRO 1
Window-type instrument current transformer CTRO 1 is designed for measurement or protection of outdoor distribution equipment operating at low-voltage level.
The primary currents can be in the range of (100–3200) A. The secondary current is generally 1 A; however, a 5 A version can also be manufactured.
The diameter of the inner cavity is 120 mm, i.e. it allows the installation of up to 2 busbars with a cross-section of 10 × 100 mm at a spacing of 10 mm.
The position of the selected busbars is dependent. The number and position of the primary conductors are determined by the value of the primary current.
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Description
All active parts of the transformer are cast in an epoxy resin compound intended for outdoor environments.
The mounting arrangement of the transformer is solved individually with regard to the electrical and mechanical requirements of the particular application.
The secondary terminal board is provided with a cover fitted with sealing screws and a cable gland Ø18/PG21.
The secondary terminal board has protection degree IP65.
Other technical parameters can be consulted with the manufacturer.
Parameters
- Highest voltage for equipment: 0.72 kV
- Power frequency test voltage: 3 kV
- Nominal primary current, In: 100 – 3200 A
- Nominal secondary current: 1 or 5 A
- Nominal short-time thermal current, Ith: max 80 kA/1s *)
- Nominal dynamic current, Idyn: max 200 kA *)
- Nominal continuous thermal current, Icth: 120 % In *)
- Accuracy class – measuring: 0.2S; 0.2; 0.5S; 0.5; 1; 3
- Overcurrent factor – measuring: FS5, FS10
- Accuracy class – protection: 5P, 10P
- Overcurrent factor – protection: 5, 10, 15, 20, 25, 30
- Nominal power: 1VА - 30VA (depending on primary current and ALF)
- Nominal frequency: 50 Hz
- Weight: 11 - 18 kg (depending on parameters)
- Thermal insulation class: E
- Operation conditions: operating temperature from -25 to +40 °C corresponds to temperature class -25/40 according to ČSN EN 61869-1
- Standard: ČSN EN 61869-2
Attached files
Drawing
