Voltage or Current Balance Relay (60)

Hope you all are fine and doing well, i need internal schematic relay (IEEE Device Numbers 60) Voltage or Current balance relay (Electro-mechanical , Static , Digital and numeric ; one of each). Need Relay of any world renowned brand like ABB , SIEMENS, ALSTOM or any other.

kindly Share link or suggest any forum member who can help me in this regard.

Engr. Zohaib Asghar
rajazohaibasghar@gmail.com
 

petersonra

Senior Member
So of late I have had to bone up a little on such things. I find the ansi relay function numbering system curious. There does not seem ti be any rhyme or reason to it.
 

Hv&Lv

Senior Member
So of late I have had to bone up a little on such things. I find the ansi relay function numbering system curious. There does not seem ti be any rhyme or reason to it.
Amen to that...
when I started in relaying I couldn’t understand what the engineers were saying as they were always talking in numbers.

I found this some some time back. It’s a “favorites” on my istuff, and printed in my computer bag.
It does a little better job with explanation IMO
 

mbrooke

Senior Member
I have a similar question.

Do you have the wiring diagram to a manual voltage balance relay? One where where two VT sets can be switched onto a single 311C/421 relay? I never liked that fact SEL has only one voltage input option for 21 & 67.
 

Hv&Lv

Senior Member
I have a similar question.

Do you have the wiring diagram to a manual voltage balance relay? One where where two VT sets can be switched onto a single 311C/421 relay? I never liked that fact SEL has only one voltage input option for 21 & 67.
That would be a true 60

some of the relays use LOP logic with 59 or 27.
So LOP would be 20% of 59L or something along those lines.
Davidbeach is right on his relays. Alarm if a PT fuse blows, but don’t trip. Also, blocking logic will stop the station tripping during blinks with time delays. So if you enable your LOP to trip, make the logic say LOP = trip if LOP greater than 3600 cycles. (Or something like that.)
Ours do that also. The 311C instructions mentions the logic isn’t designed to detect all PTs.
There is a generator sync check, but as I’m sure you know, that’s on the VS terminal only.
 

Hv&Lv

Senior Member
We don’t use LOP on our stations to operate anything. Alarm only.
We don’t use it in trip logic to operate immediately. That is where it CAN operate if something happens on the line. It’s never happened to us.
The 311C has some good factory logic that includes breaker close and or open with LOP to supervise some elements. I believe it has two or three levels of LOP protection and blocking.
It will evaluate an LOP without a corresponding loss of current.
your LOP should supervise your distance elements, directional elements, and a couple more elements.
in our other discussion in post 40 you had me concerned and thinking about what would happen when you said you could rig LOP to initiate in milliseconds, in the case of a failed CCVT to open the breaker. I still don’t think that is wise, IMHO.
if you want it to detect a blown CCVT, it needs to have some blocking logic to cover for blinks, and other things.
Of course, by then the 50/51 elements should already have the line open due to overcurrent with the bad CCVT.
 

mbrooke

Senior Member
That would be a true 60

some of the relays use LOP logic with 59 or 27.
So LOP would be 20% of 59L or something along those lines.
Davidbeach is right on his relays. Alarm if a PT fuse blows, but don’t trip. Also, blocking logic will stop the station tripping during blinks with time delays. So if you enable your LOP to trip, make the logic say LOP = trip if LOP greater than 3600 cycles. (Or something like that.)
Ours do that also. The 311C instructions mentions the logic isn’t designed to detect all PTs.
There is a generator sync check, but as I’m sure you know, that’s on the VS terminal only.
Letting you know that I read this reply. :)

I will process and comment more tomorrow.


My plan now is to have LOP trip nothing, but simply revert to a low level 50/51 unsupervised- over the normal anticipated LTE current. That way a fault of any kind will trip only through over current elements.

The way I see it is this:

VT fails and short circuits. The bus coupler trips in ~12 cycles on its zone deriving voltage from the healthy bus. Remote zone 2 clears all the lines attached to the effected bus in ~25 cycles. Sensing one phase out at the start of the event transformer bay SEL311C goes into LOP- blocking 21P and enabling a low level 50/51. 50/51 will then trip the breaker of the transformer attached to the effected bus while 21P on the other transformer will not "see" the fault passing through.

Now if we have a bus fault without losing a VT, same sequence but instead transformer bay 311C trips in about 25 cycles on a reverse zone looking into the faulted bus. The other transformer's 21P does not pick up as it is set not to "see" (reach) through the transformer.

To me this is a win-win, or as good as its ever going to get. And yes, I have you to thank over not reaching through the transformers- a really bad idea now that I run the scheme through.
 

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mbrooke

Senior Member
We don’t use LOP on our stations to operate anything. Alarm only.
We don’t use it in trip logic to operate immediately. That is where it CAN operate if something happens on the line. It’s never happened to us.
The 311C has some good factory logic that includes breaker close and or open with LOP to supervise some elements. I believe it has two or three levels of LOP protection and blocking.
It will evaluate an LOP without a corresponding loss of current.
your LOP should supervise your distance elements, directional elements, and a couple more elements.
in our other discussion in post 40 you had me concerned and thinking about what would happen when you said you could rig LOP to initiate in milliseconds, in the case of a failed CCVT to open the breaker. I still don’t think that is wise, IMHO.
if you want it to detect a blown CCVT, it needs to have some blocking logic to cover for blinks, and other things.
Of course, by then the 50/51 elements should already have the line open due to overcurrent with the bad CCVT.
Honestly, I thought about that- but have since discarded the idea.

My revised scheme is to simply block 21P on LOP and initiate 50/51. If 50/51 picks up that will be based purely on current magnitude.

At this point I think it will work, 50/51 seems gets the job done and securely.

Your post clears up my confusion regarding LOP.
 
Letting you know that I read this reply. :)

I will process and comment more tomorrow.


My plan now is to have LOP trip nothing, but simply revert to a low level 50/51 unsupervised- over the normal anticipated LTE current. That way a fault of any kind will trip only through over current elements.

The way I see it is this:

VT fails and short circuits. The bus coupler trips in ~12 cycles on its zone deriving voltage from the healthy bus. Remote zone 2 clears all the lines attached to the effected bus in ~25 cycles. Sensing one phase out at the start of the event transformer bay SEL311C goes into LOP- blocking 21P and enabling a low level 50/51. 50/51 will then trip the breaker of the transformer attached to the effected bus while 21P on the other transformer will not "see" the fault passing through.

Now if we have a bus fault without losing a VT, same sequence but instead transformer bay 311C trips in about 25 cycles on a reverse zone looking into the faulted bus. The other transformer's 21P does not pick up as it is set not to "see" (reach) through the transformer.

To me this is a win-win, or as good as its ever going to get. And yes, I have you to thank over not reaching through the transformers- a really bad idea now that I run the scheme through.
Thanks bro. Kindly share schematic of Voltage balance relay. Basically I want a Voltage balance relay 60 Schematic of all mentioned above
 

mbrooke

Senior Member
I do not have the schematic. I was wishing someone would give it to me. The issue is that SEL relays lack more than one 3 phase voltage input for MHO and directional over current. Basically they must be transferred externally based on isolator inputs.
 
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