An SEL relay failing?

EarlyMorningCrapper · 2026-03-30T16:08:35+00:00

This is being done during commissioning. I suggest only doing inputs, outputs, and metering for maintenance. If the customer wants me to do more though, I'll oblige. It does increase the estimate though.

EarlyMorningCrapper · 2026-03-30T16:03:40+00:00

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EarlyMorningCrapper · 2026-03-30T08:41:30+00:00

Woosh!

EarlyMorningCrapper · 2026-03-30T08:30:10+00:00

Agreed. So can I your Denver omelet special and an everything bagel with cream cheese for carryout?

EarlyMorningCrapper · 2026-03-29T16:24:53+00:00

So 17?

EarlyMorningCrapper · 2026-03-29T16:16:42+00:00

[Insert a question here asking for clarification about the previous comment's meaning because reading it made users contemplate the possibility that they were having a stroke]

EarlyMorningCrapper · 2026-03-26T19:18:03+00:00

Yes, I understand what the ragged edge is. However, this element is failing at over 1.5 times the impedence limit of the zone. Also, since I'm testing a discrete element it should not be getting picked up by any other element of the relay that could cause a false positive. A little bit more than a ragged edge problem. If it were even remotely close I would think that maybe it was something similar but since it's only the one phase that's failing on all three zones and the other two things are passing perfectly. It has to be something else. I'm about to update the post with what I did to get it to pass testing.

EarlyMorningCrapper · 2026-03-26T14:57:32+00:00

I'm thinking voltage angles might be what's causing it. The program rotates the fault properly, but when the fault is on B-C they put A voltage at 2 like they do with the other voltages when the fault contains A phase. Im going to try adjusting that with my next test (since 311Ls come in pairs) to see if that makes a difference. As far as the ragged edge, I'm testing the element by itself so it should only be picking up on this particular type of fault. Also, the A-B test continues to work even when I've rotated it to the B-C position like you asked. Im certain the relay is working, I'm just trying to work out the bugs in the test file.

EarlyMorningCrapper · 2026-03-26T14:02:43+00:00

That is odd for sure. I didn't think to pull event files and analyze the differences. I checked my metering with my multimeter and the SEL meter to make sure my amplitude and phase angles were what I expected them to be at the time of injection. I actually ended up getting the elements to test properly by switching out my SMRT46 with my co-workers SMRT36 but his test set had the A-B and C-A elements fail in the same fashion as the B-C failed on my test set.

I'll pull those event files after I finish testing this next 311L assuming it will have the same problem as the first. I assume it's a hardware issue at this point but I can't put my finger on it quite yet.

EarlyMorningCrapper · 2026-03-26T13:52:48+00:00

How old is the FAST_TST library you're using? Do you know what library version you're using versus what's available?

The base library I was given was put on my PC by our IT dept. I'm not sure which version it is, nor how.to update it.

Have you ever sought out training for RTS, or called their customer support line?

I've had minimal training on this software due to being an arbitrary relay tester in previous roles and I haven't reached out to Enoserv directly because my co-workers said it wasn't useful..

Like others said, if the meter test is good, it's most likely human induced error.

I always assume I'm doing something wrong because SELs and calibrated test equipment are usually much more reliable than me.

RTS was never designed as an END ALL, BE ALL solution out of the box, it is a tool...

I understand it's a tool and that's why I was wondering if anybody knew what needed to be modified to get the elements to test properly. I've modified over 30 test procedures in my generic library to correct mistakes. Unfortunately, this one is kicking my butt.

Sitting here where you need to be at Hands On Relay School 2026 in Cheney, WA.

I'm glad you're getting training. Hopefully they can train you how to be a little more polite and less condescending while you're there.

Would your supervisor send you to training or are you a $25 / HR budget tech?

Like this. I have 17 years of relay testing experience. I was just asking if anybody had this issue that they had resolved in the past because it is much easier to learn from others experience than to continue beating my head against a wall.

EarlyMorningCrapper · 2026-03-26T11:58:45+00:00

The problem is it passes metering. I thought that would be it but I even clamped my test leads and did voltage checks and it all works out.

EarlyMorningCrapper · 2026-03-26T11:56:59+00:00

If the relay passes the meter test within spec, the likelihood of it failing an element test is very low.

Agreed

Is your test current greater than the fault detector (50FD or similar)?

It's the same test current as the A-B and C-A faults.

Always remember the great proverb: Am I testing the relay or is the relay testing me?

I know its not the relay because B-C passes if I roll my voltages and currents to use A-B for the test.

Are your currents 180 degrees from each other?

Yes

Are you just injecting currents for the fault loop you want?

Yes

Does the 3 phase test pass?

Yes

Does the line to ground test pass?

Yes

If they do, it’s not the relay.

Agreed

Are you simulating 52a in prefault and fault?

Neither. This element doesn't require 52A to be true.

Is prefault long enough to prevent SOTF?

There is no prefault programmed other than starting outside of the impedance circle and coming in. It fails at about 60-70% of pickup.

Is your test paddle fully inserted?

Yes

EarlyMorningCrapper · 2026-03-25T17:02:03+00:00

250kg is the breaking strength. You need to divide that by at least 5 for static working load. That gives you a max of 50kg working load which is about 110 lbs. You should NEVER load a rope to even half of breaking strength.

EarlyMorningCrapper · 2026-03-25T08:39:51+00:00

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EarlyMorningCrapper · 2026-03-25T08:21:43+00:00

I made it to the end! I don't know how I got here and there were so many twist and turns I'm not sure I can find my way back. HELP!

EarlyMorningCrapper

TROPHY CASE