The reactive power definition in real systems has been subject to controversy and there is not one generally accepted definition of reactive power in systems with non-sinusoidal voltage and current waveforms, not to mention even unbalanced three-phase systems.

The IEEE (Institute of Electrical and Electronics Engineers) 1459-2000 standard (from 2000) does not give a formula for total reactive power for non-sinusoidal three-phase systems – as three basic types of power the standard mentioned are active power, apparent power and nonactive power designated as N.

Reactive power has been limited only to the fundamental component and designated as Q1.

This standard is the last document of this type issued by recognized organization which was to put the power definition issues in order.