Perform an Acceptance Test


Perform an Acceptance Test

Protective Relay Acceptance Testing

We perform acceptance tests to answer a couple of questions:

1. Did the relay manufacturer send us a fully functioning relay?

Modern digital relays have four basic failure points. We can perform the following tests to make sure the relay is physically working:

  • A relay self test will tell us if the power supply, or some other circuit board component, has failed.
  • An output pulse test will tell us whether any of the relay output contacts have frozen open or frozen closed.
  • An input function test will tell us if the inputs are working correctly.
  • A meter test will tell us if the analog-to-digital conversions inside the relay are working correctly.

Once these basic tests are performed, we can be confident that the manufacturer has sent us a working relay.

2. Have we, or the relay engineer, screwed up the basic connections?

When we start our relay test procedure with an acceptance test (after we connect the relay as per the site drawings instead of the manufacturer’s drawings), we are going to immediately find the obvious problems that make testing a nightmare, or prevent a relay from working correctly. Usually the problem is that you screwed up the connections, but sometimes there is a problem with the site drawings. It’s better that you find both problems now instead of later.

Watch the videos in this lesson to see how to perform an acceptance test, using different test-sets and relays.

If you skipped the introduction videos, you will need to watch the introduction video for this topic (click here to jump to it) before you will be issued a certificate.

Collapse Comments

In the ABB video around time 4:18 and a little before, I believe their is some confusion between the WYE connections shown on the drawing and the narrative. The drawing is showing how the WYE connections differ to the FT switch for WYE. The narrative is flagging a possible connection issue to the relay.

Chris Werstiuk (Administrator) November 17, 2017 at 7:21 pm

Thanks for keeping me honest! The problem actually started well before that mark and I made appropriate edits. I guess I need glasses 🙂


Leave a Comment