A polarity check for a current transformer (CT) is essential to ensure that the primary and secondary windings are connected with the correct polarity. Incorrect polarity can lead to inaccurate measurements and potential issues in protective relay operations. Below is a general procedure for conducting a CT polarity check:
To guide the responsible persons in conducting Current Transformer Polarity Check.
SAFETY PRECAUTIONS – The following Safety precautions shall be taken in consideration prior, during and after conducting the test measurements.
- Safety tagging shall be implemented.
- Isolate the Area by Safety Warning Tape.
- Keep a Safe Distance from the device being tested.
- Wear Appropriate Personal Protective Equipment(PPE) Prior to starting any testing activity.
- Implementation of Proper Grounding.
Polarity Check Procedure
- Setup the CALIBRATED test instrument in a firm, reasonably level base and dry area.
- Identify test parameters and terminals for proper connections.
- Set-up and effectively ground the test instrument. Supply voltage, 110Vac or 230Vac. Conduct testing as per the following illustrated test Connections:
- Power ON the Test Instrument and select PolCheck Test Card
- Properly fill-up test settings:
- Press I/O (test start/stop) push-button to start the test.
- Save test card for printing.
7.1For multi-tap core/s, create and save test card for each tap tested. - Note and record all necessary test parameters in standard test forms
- Evaluate test result as per general standard ratings.