Analysis of Three-Phase Systems With Neutral Under Distorted and Unbalanced Conditions in the Symmetrical Component-Based Framework

This paper introduces an original and rigorous formulation for computing the unbalance and distortion components of phase and neutral currents in the framework of the symmetrical component transformation. The proposed formulation extends recent literature results, in which different matrices were used for unbalance characterization in the presence of distorted waveforms and provides, at the same time, an innovative interpretation of the neutral current waveform components. New indicators are also defined to combine the effects of unbalance and waveform distortion, extending the set of indicators currently adopted in the power-quality standards. A set of illustrative examples is presented to show the applicability of the proposed approach. These include four circuits, two real-case applications, and an example taken from the IEEE trial-use standard 1459-2000