Without the effects of harmonics you can find the neutral current using the following:
=square root of [(A^2 + B^2 + C^2)-(A x B)-(B x C)-(A x C)]
My experience does not show the amount of harmonics that all of the information says there should be. In my opinion that is because this information is provided by people that have a vested economic interest in solving the harmonic problem.
Don
