Power Quality Indices for Unbalance Characterization in Non‐sinusoidal Condition

The unbalanced non-sinusoidal operation represents a common steady state of the modern distribution power grids. The unbalance is produced by supplying of unbalanced loads or by different unbalanced faults. According to the existing norms, this operating state is evaluated using the well-known negative and zero unbalance factors that practically keep out the harmonic pollution that coexists with the unbalance. The paper proposes a new way of determining the negative and zero unbalance factors, which takes into consideration the non-sinusoidal operating state, too. At the end of the paper, some study cases are analyzed in order to underline the difference between the existing way to evaluate the unbalance in harmonic polluted systems and the proposed one.