This article is To guide the responsible persons in conducting Voltage 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.
TEST EQUIPMENTS: OMICRON CPC-100.
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.
7.1 For 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.
What is Polarity Check of Voltage transformer?
The Polarity Check of a Voltage Transformer (VT) is a diagnostic test conducted to determine the correct polarity or phasing of the transformer’s primary and secondary windings. Polarity refers to the direction of the induced voltage in the secondary winding concerning the primary winding when a voltage is applied to the primary.
What is purpose of polarity check?
The primary purpose of the polarity check is to ensure that the connection of the voltage transformer aligns with the specified or intended phasing.
It is crucial for accurate measurements and reliable performance of protective relays and other electrical devices connected to the voltage transformer.
What is polarity check procedure?
The test involves applying a low-voltage AC source to the primary winding and observing the induced voltage in the secondary winding.
The direction of the induced voltage in the secondary winding is compared to the expected or reference direction.
What equipment is used in polarity check?
A low-voltage AC power source is used for applying the test voltage to the primary winding.
A voltmeter or a polarity tester is used to measure the induced voltage in the secondary winding.
What are safety considerations for polarity check?
The test is typically performed with low voltages to ensure safety.
Standard safety practices should be followed when conducting any test involving electrical equipment.