Richard Clark wrote:
"The very first formula from the Standard Handbook for Electrical
Engineers, Section 11. Power Transmission, Electrical Calculsations:
I = P/E (1) "

Unless a d-c transmission is specified, that`s wrong.

P=EI cos theta, where theta is the angle between E & I. For 0-deg. coa
theta=1.

Cos theta is synonymous with the "power factor" of a single phase
circuit.

I`m relying on memory which is good for old things.

Best regards, Richard Harrison, KB5WZI