IEEE Power Engineering Society

Harmonic distortion is not a new phenomenon. Concern over harmonic distortion emerged during the early history of AC power systems. Widespread applications of power electronic-based loads continue to increase concerns over harmonic distortion. Harmonic problems have sparked research that has led to much of the present-day understanding of power quality problems. The current-drawn by electronic loads can be made virtually distortion-free (i.e., perfectly sinusoidal), but the cost of doing this is significant and is debate between equipment manufacturers and electric utility companies in standards-making activities. This paper discusses the history of harmonics in power systems. It then defines harmonic distortion and discusses harmonic sources. System response characteristics to harmonics and the impact of harmonics are also discussed. Control of harmonics is also discussed.