What do you think of these phase angle readings?
What do you think of these phase angle readings?
(OP)
Part of our relay maintenance procedure we have to prove that the current and voltage inputs to the relay are correct. When we triggered the event (screen shot provided) on the SEL-311C (substation A) we saw that the phase angles didn't quite make sense (IB was almost in phase with VA). When talking to the boss he said something is wrong. We than compared the SEL phase angle readings to the bus diff relay and all the readings were the same. Doing that just proved that if the line relay readings (SEL-311C) are wrong so is the bus diff readings. We also went to the other end of the line (substation B) to check those readings expecting those to be 180° different than (substation A) and they were. So we can't find anything wrong but boss still says asks how can our angles look that bad. I know power factor and vars could throw the readings off. If these reading are correct (and I believe they are) what good is "proving" the inputs to the relay in this case? Also how would you explain these readings? If anyone has AcSELerator Analytic Assistant and wants to look more at the event I can provide that.






RE: What do you think of these phase angle readings?
Are there any relay settings that would compensate for wiring/phasing differences? How are they set?
RE: What do you think of these phase angle readings?
If it is, then your VTs are connected in delta and that adds 30 degrees to the phase angle. Or does the system correct for that?
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: What do you think of these phase angle readings?
Are there any relay settings that would compensate for wiring/phasing differences? How are they set?
PTs and CTs are Wye.
As far as the settings not sure what you mean by that, please explain
RE: What do you think of these phase angle readings?
Could you list the model numbers of the relays involved?
RE: What do you think of these phase angle readings?
The SEL-311C I only number I have is the FID=SEL-311C-R110-V0-Z005004-D-20060320
The readings on all the other equipment are the raw readings in the relay test switches.
Yes this is a 40Kv L-N 69Kv L-L
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: What do you think of these phase angle readings?
I know they just installed a new fuseless one at substation B. Think it's 15.6M mvar. You think thats why?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
Bill
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"Why not the best?"
Jimmy Carter
RE: What do you think of these phase angle readings?
Its possible that you do have a real connection problem. But you've never seen it because you aren't using functions that use an I/V relationship (Distance, Directional Overcurrent, etc.). My money is still on some delta/wye setting or display discrepancy.
RE: What do you think of these phase angle readings?
This relay (SEL-311C at substaion A) is used for DTF (distance to fault) on a electromechanical relay plane only.
"My money is still on some delta/wye setting or display discrepancy."
If this is the case how can I explain the why other end of the line at substaion B being the same as substation A only 180° out?
RE: What do you think of these phase angle readings?
How are your substations (A and B) configured w.r.t. the bank location, open breakers, etc?
RE: What do you think of these phase angle readings?
Cap bank is at substation B and now that I've talked with our control center they have had this bank in for the last week or so if that answers your questions about breaker status. There is an auto 138Kv to 69Kv at substation B. The 69Kv bus at B only has one other line on it that feeds a radially feed sub.
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
We lost one phase of a submarine cable and after a single conductor cable was laid to replace the faulty phase we could no longer depend on balanced voltages and we started using three element meters.
Yes, CT secondaries may be connected in delta.
Bill
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"Why not the best?"
Jimmy Carter
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?
RE: What do you think of these phase angle readings?