Physical Separation of Primary and Secondary Relaying
Physical Separation of Primary and Secondary Relaying
(OP)
I am curious to see how other people incorporate physical separation in primary and secondary line relays, I'm not talking about separate DC, CTs, etc.
On 115kV to 230kV transmission lines, is it necessary to use different panels?
If the two relays are on the same panel, is it best to put one close to the top, and the other closer to the bottom, or is it ok to put one close to the other?
Is there any US codes or guidlines that one can follow regarding this subject?
Thanks for the help!
On 115kV to 230kV transmission lines, is it necessary to use different panels?
If the two relays are on the same panel, is it best to put one close to the top, and the other closer to the bottom, or is it ok to put one close to the other?
Is there any US codes or guidlines that one can follow regarding this subject?
Thanks for the help!






RE: Physical Separation of Primary and Secondary Relaying
old field guy
RE: Physical Separation of Primary and Secondary Relaying
RE: Physical Separation of Primary and Secondary Relaying
RE: Physical Separation of Primary and Secondary Relaying
RE: Physical Separation of Primary and Secondary Relaying
I would agree that some physical separation on the panel is not a bad idea, but I've always maintained that confining one panel to the control and protection of one bay helps to promote a better mental picture of the overall scheme. (The word 'bay' is used as with a ring or breaker-and-a-half scheme, to control or protect that line or transformer in that bay will require interface with two breakers.)
RE: Physical Separation of Primary and Secondary Relaying
Depending on where you are and the system involved physical seperation is a requierment.
RE: Physical Separation of Primary and Secondary Relaying
Sure there may be some advantages for separating them as outline above, but the disadvantages far outweigh the advantages.
RE: Physical Separation of Primary and Secondary Relaying
It's depend on the voltage level and size of transformer or generator.
From the 400kV we usually use only two separated panels.
For the AT or T from 250-300MVA, separated paneles, same for generators.
220kV or 330kV line protection, is depend on the rules of company.
I don't like use today words : primary and secondary, prefered Main1 and Main2, lot of cases is fully dupicated scheme, for generators and transformers.
For line is 87L with 21 bacj-up and 21 with communication, etc...
RE: Physical Separation of Primary and Secondary Relaying
How is it more expensive to separate A&B protections? Especially if you are bringing all your cables to cross-tie racks? I see no issue with future upgrading of protections there.
There are pro's and con's with having A&B prtoections for the same element on the same rack. We have stations with both set ups and historically most inadvertants have happened on those racks that have A&B elements located on the same panel or adjacent to each other.
RE: Physical Separation of Primary and Secondary Relaying
Yes, there are common mode failure risks associated with having all the protection for a position in the same rack, but the day-to-day reliability impacts of spreading the protection around the control house carries far more risk.
All that to say nothing of old installations where positions get upgraded protection one at a time over the course of years and any attempt to spread it around makes for logistical nightmares.
RE: Physical Separation of Primary and Secondary Relaying
RE: Physical Separation of Primary and Secondary Relaying
The design we have used in the past is both relays in the same cabinet, with a dubiously-fire-rated (no formal rating, but it might hold for a bit...) separator dividing the cabinet in two. Wiring for A protection up one side, wiring for B protection up the other and following disparate routes to the extent practicable out to the CT's, VT's, circuit breakers, etc.
RE: Physical Separation of Primary and Secondary Relaying
I've also seen seprated cable trenches in a substation, but I've never seen both in the same substation.