hey guys,

Need help finding present harmonic distortion.

the problem states we have a 750kva transformer at 60hz running 480 3ph with 5.75% impedance.

i found FLA to be 477A.

Effective impedence is 3.04%

the question asks: Estimate the present harmonic current distortion based on FLA and Efective impedance.

any suggestions or comments would be greatly appreciated.

or even a general equation would be awesome.

 

How did you arrive at FLA=477A and effective impedance =3.04%?

 

FLA came from the NEC codebook.

3.04% impedence came from Z(effective)=Z(xfmr impedence) x actual load/ xfmr rating

actual load came from s= sqrt3(V)(I) which is 477(480)(sqrt3)

 

Presumably from your FLA value the stated 480V is the line-to-neutral voltage?