Directional Overcurrent and Earth Fault Protection relay (67/67N) Test.

Testing directional overcurrent and earth fault protection relays (67/67N) involves several steps to ensure their proper functioning.

This article is to guide the responsible persons in conducting Directional Overcurrent and Earth Fault Protection relay (67/67N) Commissioning and test procedure.

Test Equipment: Secondary Injection test kits; Multimeter; Digital Timer

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.

Directional Overcurrent and Earth Fault Protection relay (67/67N) Test.

Here’s a general outline and steps of the test procedure:

1. Perform General Visual Inspection as per work instructions.
2. Perform the tests required as per the following test connection for injection of secondary Current values to the relay:

3. Check the directional operating characteristic angle (forward, reverse and undefined).
4. Check the polarizing voltage (3Uo) Pick up and Drop off.
5. Check Earth fault over current group (non-directional & directional element).
6. Repeat step for different curves (NI, EI, LTI, DT,..etc) as per requirement or as indicated in the Test form.
7. Check the communication Fail.
8. Check all Tele-Protection Schemes (Blocking, Unblocking, Directional Comparison, Direct Transfer Trip).

It’s essential to follow manufacturer-specific testing procedures outlined in the relay’s manual and adhere to any industry standards and guidelines applicable to protective relay testing. Additionally, experienced personnel with a thorough understanding of protective relay principles should conduct these tests.