Harmonics analysis is established by international standards as well as national norms [6], [7]. There are also definitions and calculus relationships for the indicators considered representative for this non quality aspect of the electric power. Among the harmonics analysis methods, the authors have dealt with application of DFT, given the fact that were to be analyzed acquired waves experimentally, using data acquisition boards. Experiences in using DFT, difficulties and highlighted errors as well are materialized in this paper, which is of great use to practitioners in this field.

Next, there is made a distinction between the a.c. and d.c. current waves in defining the harmonics indicators, which gives accuracy and expressivity to the harmonic analysis.