Medium-voltage instrument transformers
Low Voltage Current Instrument Transformer
CTT 1
The CTT1 current instrument transformer is used for measurement and protection purposes in indoor LV power distribution systems with the highest system voltage of 0.72 kV. Their rated secondary currents are 5A or 1A.
The ultimate operating current of the CTT 1 transformers attains 120 % IN , however, another values can also be guaranteed providing that such has been agreed between the manufacturer and the customer. The required accuracy class for these transformers is met within 25% to 100% of rated burden.
The transformers are designed as slip-over devices.
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Description
The CTT1 current instrument transformer is used for measurement and protection purposes in indoor LV power distribution systems with the highest system voltage of 0.72 kV. Their rated secondary currents are 5A or 1A.
The ultimate operating current of the CTT 1 transformers attains 120 % IN , however, another values can also be guaranteed providing that such has been agreed between the manufacturer and the customer. The required accuracy class for these transformers is met within 25% to 100% of rated burden.
The transformers are designed as slip-over devices.
The terminal blocks on the secondary side are mounted in a box with multiple outlets with the possibility of lead-sealing. The conductors may enter straight on through 7 layers of M25 sealing, or be replaced with a gland. We recommend to connect the secondary terminals using bare conductors of up to 2.5 mm diameter.
As an additional service for the customer we may provide the transformers with official calibration certificate. The transformer parameters may also be tailored to the specific requirements of the client, based on previous agreement with the manufacturer.
Parameters
- Highest voltage for equipment: 0.72 kV
- Power frequency test voltage: 3 kV
- Lightning impulse test voltage: 25 - 600 A
- Nominal primary current: 5 A nebo 1 A
- Nominal secondary current: 60 x In
- Rated short-time thermal current, Ith: 2,5 x Ith
- Rated dynamic current, ldyn: 50 Hz (60 Hz)
- Nominal frequency: E
- Thermal insulation class: corresponds to the -5/40 thermal class to ČSN EN 61869-1 standard; for mounting in indoor areas without water condensation.
- Standard: ČSN EN 61869-1, ČSN EN 61869-2, IEC EN 61869-1, IEC EN 61869-2
Attached files
Drawing
