A Poynting Vector Approach to the Study of Power Flow through a Transformer

This work deals with the flow of the electromagnetic energy through an idealized single-phase transformer supplied with nonsinusoidal voltage and supplying a nonlinear load. The electromagnetic flux components of the energy that flows from primary to secondary as well as the flux of energy stored in and ejected from the dielectric space surrounding the windings are identified and quantified. The electromagnetic flux components are correlated to well known instantaneous powers. These powers are not clever mathematic expedients but correct expressions that mirror the actual physical phenomena and lead to a more realistic interpretation of apparent power and its resolution.