Harmonics-causes, effects, measurements, and analysis: an update

Rectification generates harmonic voltages and currents that can cause problems, e.g. insulation failures due to overheating and overvoltages, malfunction of solid-state equipment, communication interference, etc. The common addition of power factor correction capacitors to such a system generally increases the likelihood of such problems occurring. Online data acquisition and analysis of the harmonic content of system voltages and currents may be necessary to identify the cause properly and recommend a solution. In response to these problems, a field-proven portable harmonic-measurement/analysis system is described, as well as the advantages and versatility inherent in its use. This portable, computer-based system provides on-site data collection, precise harmonic identification via a fast Fourier transform, data analysis, and report preparation via a custom spreadsheet. Specific examples involving the application of this measurement/analysis system in the cement, steel, and carbon industries are presented.< >