Comprehensive Definitions for Evaluating Harmonic Distortion and Unbalanced Conditions in Three- and Four-Wire Three-Phase Systems Based on IEEE Standard 1459

So far, various studies are carried out in the field of unbalance decomposition from harmonic distortion in three-phase systems, and several criteria are proposed to express the value of these two types of disturbances, separately. However, most of them do not comply with the standard definitions for the effective values of three-phase voltage and current. Furthermore, extensive investigations are not performed for the calculation of the decomposition factors in three- and four-wire three-phase systems. In this paper, sequence matrices are applied to phase and line voltage and current harmonics to calculate balanced and unbalanced components. Afterwards, according to IEEE Standard 1459-2010, new distinguishing factors are extracted for three- and four-wire installations. Also, a new index is introduced as total harmonic and unbalance distortion to have an overall consideration of the system disturbance. Finally, three illustrative examples are presented to show the ability of the proposed indices in evaluating unbalance and harmonic distortion in three-phase systems.