Limiting low frequency interharmonic distortion and voltage fluctuations

Limiting low frequency interharmonic distortion and voltage fluctuations is considered. Reference is made to recent activities in the standard review process and to research literature regarding this specific topic and related issues. Some recalls on the main low frequency interharmonic voltages effects are reported. Then, the problems related to the combined use of limits and assessment procedures based on IEC flickermeter and on IECDFT spectral analysis together with the sub-group concept are discussed.