Evaluating the Level of Waveform Distortion

Analysis of the influence of selected non-linear devices on the waveform of supply voltage

“…The PN-EN 50160 standard [12] specifies that when assessing voltage quality, higher harmonics up to the 40 th order should be taken into account when calculating the total harmonic distortion of voltage (THDU). In works [14,15] the author showed that such a limitation may lead to incorrect assessment of waveform distortion, therefore in the present paper both THDI -total harmonic distortion of current and THDU -total harmonic distortion of voltage were calculated taking into account 127 and 511 components respectively. The number of components results from the measurement capability of the equipment used…”

The Influence of Measurement Methodology on the Accuracy of Electrical Waveform Distortion Analysis

“…In order to gain the accurate assessment of the electrical waveform distortion, the distortion components have to be representative and integral to reality. The authors of numerous works [6], [8], [23], [24], [25], [26] indicate that restriction of the spectrum suggested in the norm [10] to 50 components may be the reason for the discrepancies. In work [23] presents the practical example of the supply voltage on a ship.…”

“…It was probably caused, among others, by a reduced range of analyzed spectrum, according to the norm [10]. Further studies [6], [26] indicated that narrowing the spectrum of harmonics may affect other parameters that describe electrical waveforms such as effective value (RMS), waveform distortion factor (THD), and crest factor (CF).…”