Power system even harmonics and power quality indices

Y. Liu, G. T. Heydt

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


This article deals with the even harmonic components (especially second harmonic components) in power system voltages and currents. The power system even harmonic components can be generated from semi-controlled three-phase rectifiers and dc-biased transformers. Those components cause unequal positive and negative peak values, which are called waveform asymmetry. Waveform asymmetries have a harmful impact on the loads sensitive to voltage or current peaks. The usual power quality indices (e.g., total harmonic distortion, telephone inference factor) are well defined for even harmonics. However, none of those indices can capture the waveform asymmetry. Total even harmonic distortion (TEHD) is proposed to consider the special effect of even harmonics. A new index, asymmetry factor (AF), is proposed for the waveform asymmetry. The difference between the AF and the crest factor (CF) is clarified. Simulation and laboratory results are reported.

Original languageEnglish (US)
Pages (from-to)833-844
Number of pages12
JournalElectric Power Components and Systems
Issue number8
StatePublished - Aug 2005


  • Even harmonics
  • Harmonics power quality
  • Power distribution systems
  • Power electronics
  • Rectifiers

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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