Product Introduction

DBCT-X Calibrator of Instrument Transformer is developed based on users’ field requirements. The calibrator may satisfy the users on measuring errors of current transformers (ratio error, angle error). With the high accuracy, good stability, small dimension, and light weight features, this instrument provides great convenience for users.

Product Features

l  The field current transformer error tester adopts the recurrence method to measure the current transformer errors, offering convenience for field verification of metering device.

l  The field current transformer verification requires no standard current transformer, current amplifier, load box, voltage regulator controls and large-current conductor. Instead, it uses very simple test wiring and operation to realize the current transformer verification, greatly reducing the work intensity, improving the work efficiency, and providing convenience for field verification of current transformer.

l  The field current transformer error tester includes a standard current transformer of a transformation ratio equivalent to that of the current transformer under test, which can achieve the accuracy up to Class 0.02, equivalent to a Class 0.05S current transformer. It can accurately measure the transformation ratio and no-load error of a current transformer. Then, the current transformer error can be calculated in combination with the test results of impedance and admittance.

l  A power supply of pilot frequency close to power frequency is used in the test to prevent the field interference from the power frequency electromagnetic radiation and series connection.

l  Wide metering range: it can measure both the current transformer of standard transformation ratio and current transformer of non-standard transformation ratio.

l  The verification device of the transformer calibrator can be used to verify the accuracy of the built-in transformer calibrator of the instrument.

l  The field data are directly rounded off to judge whether they are qualified or not.

l  Measure the errors (angle error, ratio error) of current transformers with standard transformation ratio and non-standard transformation ratio at regulation points of 1%-120% (Class S).

l  Measure the errors (angle error, ratio error) of current transformers with standard transformation ratio and non-standard transformation ratio at arbitrary points of 1%-200% (Class S).

l  Primary measure and display the errors (angle error, ratio error) of the current transformer at regulation point and arbitrary point under the upper load limit and lower load limit.

l  Primary measure and display the errors (angle error, ratio error) of the current transformer at regulation point and arbitrary point under any actual load.

l  Verify the polarity and ratio of known current transformer and unknown current transformer, and judge the actual current ratio of the unknown current transformer, and fuzzily judge whether the secondary current of the unknown current transformer is 5A or 1A.

l  Intelligently judge the state of the external wiring, and prompt the wiring mistake, transformation ratio and polarity mistake, etc. Automatically round off the tested data, and whether the data are out of tolerance.

l  320*240 large LCD display, all interface in Chinese. Easy to operate and wire up, and easy to carry.

l  The data measured can be stored and printed on-site, facilitating future enquiries by users.

l  The instrument can be connected to computers through the standard USB interface for data transmission, and backstage management software can process the reports and print the document in accordance with national standards.

l  The rack shall be made of shockproof and pressure-resistant material, so as to guarantee the safety of field operator and equipment.

l  The overall weight is no more than 5.0kg. Overall dimension: 323mm×275mm×135mm. Its small dimension and light weight make it easy to carry.

Technical Specifications

1.      Transformation ratio range:

5A/5A-25000A/5A (5A/1A-5000A/1A) Turns ratio error ±0.2%

2.      Error measurement range:

5A/5A～5000A/5A（5A/1A～5000A/1A）

3.      Accuracy range of the current transformer under test: 1.0, 0.5, 0.5S, 0.2 and 0.2S

For the 1% (Class S) or 5% test point, the test error comes mainly from the deviation caused by the automatic measurement of the instrument, i.e., the dial indicator reading deviation and deviation of the single turn from the center (the two deviations also exist in the traditional verification method). Therefore, when comparing the two verification methods, you may find that the error is big or small.

4.      Accuracy of complete machine: 1/3 of the error limit of the current transformer under test (see Appendix I) (Note: The errors caused by the standard current transformer and the calibrator are, respectively, 1/5 and 1/10 of the error limit, and the errors caused by Δε (no more than 1/2 of the error limit of the current transformer under test) and Z are both 1/10 of the error limit of the current transformer under test, the error caused by the electromagnetic field is 1/10 of the error limit of the current transformer under test, and other errors are 1/10 of the error limit of the current transformer under test. The composition error will add according to the root-mean-square of the above stated errors, is 1/3.33, smaller than 1/3, of the error limit of the current transformer under test. )

Accuracy:     ±0.05% 

See the table below:

5.      DC resistance:      0.0-0.1Ω      ±3%

0.1-50Ω       ±1%  

6.      CT secondary load:   1Ω－25Ω      ±2%

7.      Verification of calibrator: Voltage scope: 0-100V (dial indicator error 0.5%)

a)     Ratio error: 0.001%-3%  （100V）

b)     Angle error: 0.00′-50′（100V）

c)      Error:  DX=±(2%×X+2%×two characters)

DY=±(2%×X+2%×Y± two characters)

d)     Admittance: 0.1mS-99.9mS

e)     Error:  DX=±(2%×X+2%×Y± two characters)

DY=±(2%×X+2%×Y± two characters)

8.      Operating conditions:      AC  230V± 10%/50Hz±2%

9.      Environment temperature:      0－40℃

10.   Environment humidity:      <85% at the temperature of 25°C

11.   Weight of complete machine:      ≤5Kg

12.   Dimension of complete machine: 323mm×275mm×135mm