NCEES 518

[mudpuppy]

Chicago and jdd: Both of your methods look like they work. I personally use the method jdd is using because I find I make fewer errors that way (in chicago's method I always forget if it's Sold/Snew or Snew/Sold). But as always, you should use whatever makes the most sense to you.

Cabby: looks like you've hit the nail on the head. I've always calculated per-unit problems on a phase basis too (it takes more calcs, but I have to remember fewer equations that way).

 

[grownupsara]

Maybe I'm over-simplifying this, but I just used eqn 28.11 from EERM (basic equations for xfmr turns ratio): IpVp=IsVs, then solved for Ip=Is*Vs/Vp=75.93A*132kV/13.2kV=759.3A

 

[Flyer_PE]

Maybe I'm over-simplifying this, but I just used eqn 28.11 from EERM (basic equations for xfmr turns ratio): IpVp=IsVs, then solved for Ip=Is*Vs/Vp=75.93A*132kV/13.2kV=759.3A

You're not oversimplifying it at all for the solution to the problem in the NCEES book. This thread just took a right turn into PU analysis since that particular problem/circuit is a good example for use in playing with the concept.

Jim

 

[grownupsara]

You're not oversimplifying it at all for the solution to the problem in the NCEES book. This thread just took a right turn into PU analysis since that particular problem/circuit is a good example for use in playing with the concept.
Jim

Oops, okay. Sorry for just jumping in on the discussion!

 

[EngrinSF]

Hello,

I wanted to revisit this problem since I am a bit confused on the terms used. I calculated the load current in the generator as the full load current: 

IGen=50MVA/(sqrt3*13.2kV)=2187 Amps

and chose this answer which turns out is wrong. Why is this  answer not right?

 

[knight1fox3]

Whoa! @ptatohed, this is quite possibly the largest time bump I've seen to date. Almost 11 years! Well done!  :appl:

 

[ptatohed]

LOL.

Grave Digger!

 

[EngrinSF]