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Function 50 and 50P

Function 50 and 50P

Function 50 and 50P

(OP)
Hi!
¿Does anyone know the diference between the protection functions 50 and 50P. The same thing with 51 and 51P.?
Im not taking about 50/51N
In some projects I saw that engineers make diference between 50 and 50P

Thanks in advance

Martin

RE: Function 50 and 50P

50P usually means phase instantaneous overcurrent.  50 usually means the same thing.

RE: Function 50 and 50P

(OP)
That's the point!
Usually menas the same, but protection engineers make diference between 50 and 50P. That way my question

regards

martin

RE: Function 50 and 50P

If these are Schweitzer relays, they generally use P to designate Phase functions.  Some protection engineers have elevated SEL internal relay designations above IEEE and ANSI standards.

   

David Castor
www.cvoes.com

RE: Function 50 and 50P

It's same 50 and 50P.
In few newer relays used also 50P-1, 50P-2.
Actually it's DT overcurrent function.
Best Regards.
Slava

BTW, for example: Siemnes 7SJ800

RE: Function 50 and 50P

Before there were multifunction numerical relays, there would be a 50 relays for phase protection and a seperate 50 for zero sequence protection 50N. With the newer relays there needs to be a way of differentiating between the different available protective devises included within the one packaged relay. 50P, 50N, 50R, 67P, 67N...

Gabe

RE: Function 50 and 50P

Quote:

Usually menas the same, but protection engineers make diference between 50 and 50P.
Give us an example in context.

RE: Function 50 and 50P

Engineers & manufacturers often get the numbers mixed up - I never rely on these numbers. Have seen costly mistakes made, and many unneccessary arguments because of this numbering system.
Get the person who mentioned the numbers to clarify the application - asking others to interpret what another person intended is normally the cause of the mistake/argument.

RE: Function 50 and 50P

Quote:

Get the person who mentioned the numbers to clarify the application - asking others to interpret what another person intended is normally the cause of the mistake/argument.

Can't agree more!

Rafiq Bulsara
http://www.srengineersct.com

RE: Function 50 and 50P

I have seen '50', or actually '50/51' been used about combined overcurrent relays. The relay contains different functions, or modules, such as 50/51P for positive sequence, 50/51G for zero sequence (residual, ground), and 50/51Q for negative sequence currents.

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