HARMONICS - CAUSES, EFFECTS, MEASUREMENTS, AND ANALYSIS - AN UPDATE

Modern technology has made possible the rectification of ac power to dc power using static rectifiers for dc drives as well as static inversion for ac drives. Although more versatile than past methods, these newer technologies may have detrimental effects on the quality of the ac system, especially when they comprise a significant portion of the system. 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. On-line 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-measuremenVanalysis 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. © 1990 IEEE