nullsig
Member
- Location
- Louisville KY
Sorry if this is the wrong forum to post this in but I figured it's a calculation question. I'm studying for the PE and going through the NCEES prep exam. Here's a question for which I'm struggling to understand their answer: https://i.imgur.com/gIJfp3O.jpg
The solution indicates that merely multiplying the transmission line current by the transformer turn ratio (132/13.2) gives you the generator load current (760A). I don't think this is right- wouldn't it be the transmission line current multiplied by SQRT(3) AND the turns ratio because it would be converting from wye to delta? Otherwise, simply multiplying by the turns ratio would only give you the phase current on the delta side, not the line current? My research and calculations all come out to answer B.
Here's some sources on Delta/Wye conversions as well that I'm using to support my argument:
https://www.myodesie.com/wiki/index/returnEntry/id/3035
https://electrical-engineering-portal.com/3-phase-transformer-connections
I'd really love if someone proved me wrong because there's nothing worse than being misled by an incorrect answer :?
The solution indicates that merely multiplying the transmission line current by the transformer turn ratio (132/13.2) gives you the generator load current (760A). I don't think this is right- wouldn't it be the transmission line current multiplied by SQRT(3) AND the turns ratio because it would be converting from wye to delta? Otherwise, simply multiplying by the turns ratio would only give you the phase current on the delta side, not the line current? My research and calculations all come out to answer B.
Here's some sources on Delta/Wye conversions as well that I'm using to support my argument:
https://www.myodesie.com/wiki/index/returnEntry/id/3035
https://electrical-engineering-portal.com/3-phase-transformer-connections
I'd really love if someone proved me wrong because there's nothing worse than being misled by an incorrect answer :?