Could power properties of three-phase systems be described in terms of the Poynting vector?

The Poynting vector (PV) and Poynting theorem (PT) are fundamental mathematical tools for calculating energy flow, its dissipation, and storage in electromagnetic fields. Therefore, there are opinions that power properties of power systems should be described in terms of the PV and PT. This paper investigates whether or not the PV and PT provide an explanation of power properties and whether or not they enable calculation of powers in three-phase systems. It is demonstrated in this paper that only the instantaneous power and active power can be expressed in terms of the PV but not the reactive, apparent, and unbalanced powers as well as the power factor. Consequently, the PV and PT do not provide information useful for physical interpretations of power properties of power systems. Also, they are useless for practical applications of power theory to power system problems, such as compensation.