# NCEES Problem 540



## CeeYem (Mar 12, 2021)

Please advise if I am wrong with the Zpu calculation. 
NCEES solution used Generator X'd as Generator Impedance (without considering resistance).
Attached are the question and the workout


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## Zach Stone P.E. (Mar 12, 2021)

Equal X/R ratios are being assumed for this problem. Typically (but not always), you assume equal X/R ratios for simplified fault current analysis using either the MVA method and Per Unit Method.

This problem has also been discussed many times on engineer boards. You can locate these threads by searching "NCEES 540" in the search box.


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## CeeYem (Mar 12, 2021)

Zach Stone P.E. said:


> Equal X/R ratios are being assumed for this problem. Typically (but not always), you assume equal X/R ratios for simplified fault current analysis using either the MVA method and Per Unit Method.
> 
> This problem has also been discussed many times on engineer boards. You can locate these threads by searching "NCEES 540" in the search box.


Thanks, Zach. Much appreciated


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