About some Effects of Voltage Distortion on End User’s Equipment

Abstract

The main objective of the paper is to assess the influence of supply voltage distortions, especially voltage harmonics on end user’s equipment. Generally, harmonics are probably the most important issue of power quality, greatly influencing power flow. In the introductory section, the main definitions of power quality and the main methods of harmonic analysis, namely Fourier series, Fourier transform and Wavelet transform. The second section, devoted to experimental results, presents a series of measurements carried out for a setup composed of a programmable source supplying an induction motor, as end user equipment. The motor is supplied successively with three types of voltages, a clean sinusoidal voltage and two distorted ones, namely a 50% clipped voltage and a square voltage, synthesized according their harmonic content, and downloaded to a programmable supply source. The latest two waveforms are not arbitrarily chosen, being often encountered in practice, especially when the equipment is supplied through UPS’s or power converters. The load torque of the motor was adjusted by a controlled electromagnetic powder brake. Concluding, it can be said that distorted supply voltages, having an important harmonics content, highly affect the equipment operation, especially in terms of efficiency.