Tranformer Power Calculation

[7JLAman4]

The formula for an unbalanced Wye transformer output is as follows:
I(L) = SQRT[I(A)^2+I(B)^2+I(C)^2-[I(A)I(B)]-[I(B)I(C)]-[I(C)I(A)])
What is I(L)? In a balanced Wye system, I(L) = I(Ph). This equation given for an unbalanced Wye load is puzzling. At what location would this be measurable?

 

[7JLAman4]

Just found the answer. I(L) in the equ. above is to be I(N) or the current flowing on the neutral conductor. Went back to the math and derived the equ. The formula was posted incorrently.