Harmonics-causes, effects, measurements and analysis-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. Rectification generates harmonic voltages and currents which can cause problems, e.g.: insulation failures due to overheating and overvoltages; malfunction of solid-state equipment; and communication interference. In the present work, the authors describe a field-proven, portable, harmonic measurement/analysis system for monitoring such harmonic voltages and currents. This 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