Evaluation of line voltage drop in presence of unbalance, harmonics and interharmonics: theory and applications

The paper deals with the line voltage drop calculation in presence of disturbances in the electric network, like unbalance, harmonic and interharmonic components. The Park approach permits to define a calculation expression with a structure very close to the classical one typically employed in case of balanced systems and also permits to underline the role of the imaginary power that quantifies in one term only the effects of disturbances on the voltage drop. In order to text the effectiveness of the proposed methodology, two applications on real industrial plants are presented in the second part of the paper. The comparison with the classical theory and calculation made by using commercial software gives rise to interesting comments and discussion on the proposed approach.