Title:How to Test Phase Sequence Protection (37) of a Protective Relay Using a Relay Tester

The phase sequence protection (37) of a protective relay can be tested using a relay tester. The protection principle is to monitor the phase sequence of the power system and trip the relay if an incorrect phase sequence is detected. 

To test the phase sequence protection (37), follow these steps: 

1. Connect the relay tester to the protective relay according to the wiring diagram provided in the relay manual. 

2. Set the desired test parameters on the relay tester to perform the phase sequence test. 

3. Apply a test voltage to the protective relay within the range specified in the relay manual. 

4. Observe the relay's behavior during the test. The relay should trip when an incorrect phase sequence is detected. 

5. Analyze the test results using the manufacturer's instructions provided in the relay manual. 

It is critical to ensure that the test voltage is accurate and that the wiring connections are correct. The relay tester used for the test should also be calibrated to ensure that accurate results are obtained. 

By following these steps and verifying the accuracy of the results with the manufacturer's instructions, it is possible to effectively test the phase sequence protection (37) of a protective relay using a relay tester.