Can anybody help me with a PU Transformer/Genrator question?

[NL5]

Yes, it's homework. I'm not looking for someone to do the work, just give me a general outline on how to solve it. We just started per unit calculations, and it's throwing me for a loop.


edit - here is the question -

A Single Phase Generator Rated 200
MVA, 100 KV and a Transient Reactance of 15%
Feeds A Load Through A 100 MVA, 100/10 KV
Transformer With A 5% Impedance.
What Are The Actual Short Circuit Currents At The
Secondary and Primary of the Transformer If The
Secondary of the Transformer Is Shorted To
Ground?

 

[NL5]

Anybody??? I'm completely lost.....

If someone can just tell me what order to solve the equations in it would help a ton.....

 

[Q]

Oh man, glad I'm wimping out and doing an easy major. Good luck bump!

 

[Fritzo]

My favorite Transformer was Omega Supreme. Not sure if he had impedance or not, but I'm sure they had robot viagra for that.

 

[PottedMeat]

Originally posted by: NL5

Transient Reactance of 15%
Transformer With A 5% Impedance.

no idea what that means
so thats what you learn in power systems

 

[NL5]

Originally posted by: PottedMeat

Originally posted by: NL5

Transient Reactance of 15%
Transformer With A 5% Impedance.

no idea what that means
so thats what you learn in power systems

It's per unit percentages. It's the way almost all utility transformers are rated - and confusing as hell.

 

[Regs]

[X.sub.EQ]/[R.sub.EQ], where [X.sub.EQ] and [R.sub.EQ] ?

 

[Regs]

If these are short circut calculations then this article will likely help you do the calculations:

http://ecmweb.com/mag/electric...t_calculation_methods/

 

[NL5]

Originally posted by: Regs
If these are short circut calculations then this article will likely help you do the calculations:

http://ecmweb.com/mag/electric...t_calculation_methods/

That's close on the "classic equation" section, but I still am not sure how to apply it. I'm just about out of time, so it looks like I may just have to do a best guess solution.

 

[NL5]

One last try.....

 

[krylon]

All your base

 

[coloumb]

Does this help?

Computer-aided power system analysis example

 

[NL5]

Originally posted by: coloumb
Does this help?

Computer-aided power system analysis example

That kinda the same deal as the other link that was posted.

I guess what I need to know is how to factor the generator in. I can get the short circuit currents for the high and low side of the transformer, I just don't know how to account for the generator.