Medium-voltage instrument transformers
Low voltage current instrument transformer
CLH 60
The CLH 60 current instrument transformer is intended for measurement and protective purposes in indoor LV switching stations with the highest system voltage of 0.72 kV. The rated secondary current is either 5A or 1A. The transformers meet the requirements on the required accuracy class within 25% to 100% of rated burden range.
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Description
The CLH 60 current instrument transformer is intended for measurement and protective purposes in indoor LV switching stations with the highest system voltage of 0.72 kV. The rated secondary current is either 5A or 1A. The transformers meet the requirements on the required accuracy class within 25% to 100% of rated burden range.
The ultimate operating current attains 120 % IN and, after consultation with the manufacturer, transformers with other values may also be delivered such as with 160 % of IN for rated currents ranging within 75 A to 1000 A, or 140 % In for currents ranging from 1000 A to 1500 A.
Active parts of the CLH 60 transformers are placed in plastic boxes made from high-quality plastic material. The insulation plastic materials meet the requirements on temperature insulation class E. The transformers are designed as slip-over devices having a number and position of primary conductors (copper bars) which depends on the primary current (IN ≤ 1000 A for horizontal mounting, IN > 1000 A for vertical mounting).
The secondary terminals with contact screws are located in the upper part of the transformer under a transparent cover which may be sealed. As regards the connection of secondary terminals we recommend using cable lugs of sizes corresponding to the cross-section of the connecting wire, or bare conductors of up to 2.5 mm2.
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
- Nominal primary current: 75 - 1500 A
- Nominal secondary current: 5 A or 1 A
- Rated short-time thermal current, Ith: 60 x In (max. 50 kA)
- Rated dynamic current, Idyn: 2,5 x Ith
- Nominal frequency: 50 Hz
- Thermal insulation class: E
- Operation conditions: 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
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