# NCEES #538



## Rei (Feb 25, 2010)

Could someone explain this problem to me? What would the diagram looks like if it one of the other three schemes listed in the answer choices?


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## Flyer_PE (Feb 25, 2010)

This one is just an exercise in looking up device numbers and figuring out what they mean in the circuit.

ANSI/IEEE std C37.2 is a list of standard device numbers.

27 = Undervoltage relay

52 = ac circuit breaker

79 = reclosing relay

CC indicates a close coil for the breaker.

If it were a tripping scheme, you would see 52-1/TC rather than 52-1/CC.

If it were a synchronism check scheme, the 79 device would be replaced by a 25 device.

A bus failure scheme would likely involve an 86 (lockout) device.


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## Rei (Feb 25, 2010)

How did you know all of this? Can you just take the test for me?


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## MSEE_PE (Feb 26, 2010)

Rei said:


> How did you know all of this? Can you just take the test for me?


It might be a good idea to take with you in addition to the books 3 hole binder...You can get a list of the relay numbers and what each one is for...that would be a good idea cuase that's the kind of question where you either know or you don't.


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## GTOShoota (Mar 15, 2014)

I have the IEEE text of these devices, but does anyone know of a good source to learn about different types and standard schemes in use?


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## Locchamp1 (Mar 15, 2014)

Sorry for the stupid question but I am new to this site what do you mean by ncees #538? Where can I get these problems?

Thanks


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## knight1fox3 (Mar 15, 2014)

Locchamp1 said:


> Sorry for the stupid question but I am new to this site what do you mean by ncees #538? Where can I get these problems?
> 
> Thanks


The topic is in reference to one of the problems from the NCEES power sample exam and solutions. You can get more information here.


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## Locchamp1 (Mar 15, 2014)

Thanks for the response but one more question the book only has 80 questions so how is it #538?


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## knight1fox3 (Mar 15, 2014)

Not sure how they came up with their number system. But the AM questions are in the 100's and the PM questions in the 500's. Perhaps someone else knows why they numbered them the way they did.


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## Locchamp1 (Mar 15, 2014)

Thanks a lot I will buy this book ASAP


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