Transformer Field Calibrator

Smart Current Transformer Field Calibrator

EHG-WC Intelligent Current Transformer Calibrator; This instrument is a transformer tester developed based on a detailed analysis of the mathematical model of transformers. When calibrating transformers, it eliminates the need for a voltage regulator, high-current booster, standard transformer, or load box. Simply bring this instrument to measure the ratio error and phase angle error of current transformers according to national standards. It can also measure the ratio error and phase angle error at any percentage between 1% and 120% of the current. It directly measures the transformation ratio of both current and voltage transformers; qualitatively assesses the ratio error and phase angle error of voltage transformers; and enables on-site measurement of actual secondary loads for current and voltage transformers, making calibration exceptionally convenient. The instrument employs high-precision, automatically linear-regulated DC and AC power supplies; high-speed, highly reliable digital processing modules; and high-accuracy, high-stability front-end measurement circuits to ensure measurement accuracy and stability. Additionally, it features a user-friendly interface with wiring and operation prompts, along with functions to save any measurement parameters and print results.

1: Current transformer error measurement section

• Overall accuracy: 1/3 of the error limit of the current transformer under test.
• Test range: 5A/5A~25000A/5A or 5A/1A~6300A/1A

♦ Note: A current transformer with a secondary current of 1A can have a transformation ratio of up to 31500A/1A through the equal ampere-turn measurement method.

The test methods for the current transformer ratios of other current transformers not listed in the table are as follows:

To test current transformers using the equal ampere-turn method, for example, to test a 1000A/5A transformer, please pass the test leads provided with the instrument through the core of the current transformer under test for two turns. Then, input 500A as the primary current in the current transformer test interface of the instrument. This testing method does not affect the validity of the transformer test data.

Similarly, other ratios are handled using the following methods:

③ Operating range of the current transformer under test: 1%～200%

④ Secondary load: 2.5VA～300VA, COSφ＝0.1～1.0

⑤ Accuracy range of the current transformer under test: 1.0, 0.5, 0.5S, 0.2 and 0.2S

⑥ Resistance and admittance measurement error ≤ 5.0%

Measurement range: R: 0.00Ω～20.0Ω

1.Y: 0.000mS～100.0mS

2. Instrument power consumption: 20VA

3. Instrument accuracy class: 0.05S class

1. The current transformer calibrator integrates both the iterative method for measuring current transformer errors and the potential difference method for measuring voltage transformer errors, facilitating on-site verification of metering devices.

2. On-site CT calibration eliminates the need for standard CTs, current boosters, load boxes, voltage regulator control boxes, or high-current cables. Calibration is achieved through extremely simple test connections and operations, significantly reducing workload intensity and enhancing efficiency, thereby facilitating on-site transformer calibration tasks.

3. The instrument incorporates an internal standard voltage transformer matching the current transformer's transformation ratio, achieving Class 0.05 accuracy. It precisely measures the current transformer's transformation ratio and no-load error. Combined with impedance and admittance test results, it calculates the transformer's total error.

4. Utilizes a power supply with a frequency close to the power frequency to prevent electromagnetic radiation and series interference at the site.

5. Wide measurement range: 5A/5A to 25000A/5A or 5A/1A to 6300A/1A.

6. Features current transformer ratio and secondary winding direct resistance testing functions.

7. Equipped with an 800×480 high-resolution large-screen color LCD display, featuring a user-friendly interface and operation design for enhanced convenience and efficiency.

8. Utilizes precise software algorithms to further improve measurement data accuracy.

9. Includes intelligent external wiring status detection, alerting for wiring errors, ratio errors, polarity errors, etc.

10. Automatically rounds test data and determines if it exceeds tolerance limits. Out-of-tolerance data is highlighted in color, with a tolerance warning displayed in the lower-right corner of the window, providing an intuitive overview of the transformer's data characteristics.

11. Directly issues on-site verification conclusions: Pass or Fail.

12. Large-capacity memory stores up to 2000 on-site test data entries.

13. Equipped with a micro printer for on-site data printing; alternatively, data can be uploaded via RS232 or USB interface to a computer and printed as certificates using management software.

14. Features an engineering plastic molded chassis for shock and pressure resistance, ensuring safety for field operators and equipment.

Suitable for substations, power project acceptance, and instrument transformer operation and maintenance scenarios, enabling on-site verification, fault troubleshooting, and accuracy re-evaluation of CT/PTs.