What causes harmonic currents?
Nonlinear loads are the source of harmonic currents. That is, the loads current waveform is non-sinusoidal. As a result, the distorted current waveform is rich in sinusoidal harmonic current waveforms. Nonlinear loads include electronic devices such as rectifiers, current controllers, AC and DC drives, cyclo-converters and devices with switch-mode power supplies such as computers, monitors, telephone systems, printers, scanners, and electronic lighting ballasts. 4. What causes harmonic voltages? The electrical distribution systems harmonic impedances cause the load-generated harmonic currents to produce harmonic voltages (EH = IH x ZH). Transformers, and feeder and branch circuit impedances will cause maximum voltage distortion at the nonlinear loads. 5. Is there really a harmonics problem? Yes, there is a problem. In fact, there are so many significant harmonics problems that hundreds, if not thousands, of theses, papers, articles and case studies have been published on this subject.
