During normal operation, a current transformer (CT) transforms higher Every CT test sheet . There are two generally accepted methods of testing a. CT's. Current transformer testing, calibration and assessment. The CT Analyzer automatically determines all relevant current transformer values and compares the. Specialized testing for CT continuous current FES In-service CT testing (cont.'d). Secondary access .. Testing procedure (BCTs and GCTs). ▫ Record. ▫ CT.


Author: Hank Quitzon
Country: Mongolia
Language: English
Genre: Education
Published: 10 November 2014
Pages: 783
PDF File Size: 33.23 Mb
ePub File Size: 10.67 Mb
ISBN: 883-5-22032-127-6
Downloads: 24502
Price: Free
Uploader: Hank Quitzon


CT Analyzer

Accuracy can be ensured as follow: The circuit connection shall be made as shown Figure 4. Primary Injection Test This test is ct testing procedure ensure the CT circuits are properly connected with respected cores and there is no mix up in the circuit phase identification.

The circuit connections shall be made as shown in Ct testing procedure 4. Single point grounding shall be verified for CT circuits, before starting this test. Measure secondary current at all points of CT circuits.

It shall be ct testing procedure for other phases. When one CT is having several cores used for different purposes. The cores can be identified during primary injection test by shorting the one of the core at CT terminal itself and check there ct testing procedure current only at relevant load.

The same can be verified for other cores. This test verifies that the CT is of correct accuracy rating, has no shorted turns in the CT and no short circuits are present in the primary or secondary windings of the CT under test.

6 electrical tests for Current Transformers explained

Insulation Resistance Test The insulation between the current transformer windings and windings to ct testing procedure should be checked for dielectric strength while performing a comprehensive CT test. Three tests are performed to determine the condition of the insulation of the CT under test: Checks the condition of ct testing procedure insulation between high to low.

Checks the condition of the insulation between high to ground. Checks the condition of the insulation between low to ground. Insulation resistance readings should remain fairly constant over a period of time.

  • CT Analyzer - OMICRON

A sharp dip in trending of insulation resistance values point towards insulation degradation and further investigation is required to diagnose the problem.

Insulation tests on current transformers ct testing procedure usually performed at VDC. Prior to testing, short the primary winding of the CT under test by connecting H1 and H2, then short the secondary winding of ct testing procedure CT under test by connecting X1 and X2-X5.


Remove the neutral ground and isolate the CT from any associated burden. After the windings are shorted, ct testing procedure CT will be a three terminal specimen.

Three ct testing procedure resistance tests are performed to determine the condition of the insulation of the CT under test. Insulation resistance test values for CT's should be compared with similar ct testing procedure obtained with previous tests.

Any large deviation in historical readings should call for further investigation. The minimum insulation resistance that is accepted is 1 Megohm. Any reading in Megohms is ct testing procedure to be a good insulation, however, it's the trending of insulation test results that gives the true condition of CT insulation.

Insulation readings are greatly affected by the specimen temperature. Should a reading be compared to previously taken readings, proper correction factors need to be applied, if taken under different temperature conditions before drawing any conclusion.

Testing and Commissioning of Current Transformer

Winding Resistance Ct testing procedure The DC winding resistance measurement is an important measurement in accessing the true condition, state and accuracy of a CT. Winding resistance in a CT will change over a period of time depending on the specimen age, use, external conditions and loading effect.

It is recommended to measure DC winding resistance periodically on a single tap or multi tap CT and trend the ct testing procedure. A high precision low resistance measurement circuit is required to obtain this small winding resistance.