Relevant aspects for harmonics evaluation of industrial plants: a scope from real cases

In this paper several situations concerning harmonics evaluation of real industrial plants are presented. Basically the situations are related to resonances, harmonic measurements across current and potential transformers, resonant filters design, filters operation criteria and power factor control. The effect of experimental frequency response of real current and potential transformer is considered in the scope of distortion factors THD (total voltage harmonics distortion) and TDD (total current demand distortion) given by IEEE 519 Standard. Finally, based on real situations and in the attempt to be a help for harmonics analysis, several comments and recommendations are given.