Active electrical power of harmonics and interharmonics induced by frequency converters

Modified electrical active power formulae of circuits with nonlinear load for the case of nonsinusoidal voltage and current of the circuit are presented. The classical active power is "enriched" by an additional active power which is a result of the harmonic content in the current and voltage across load. A modified formula for total harmonic distortion to characterise the degree of sinusoidal shape of current and voltage deformation is introduced. Examples of commercially available industrial equipment which are the source of harmonics and interharmonics, as well as harmonic and interharmonics content, are presented.