Characterizing nonlinear load harmonics using fractal analysis

Power quality has become a major concern to both utilities and their consumers because equipments currently are more sensitive to power quality related disturbances. One of the power quality concerns that have received most attention is the problem of harmonics which are generated by widely dispersed nonlinear loads. In order to fully understand the problem of harmonic distortion, an effective means of identifying the harmonic patterns generated by different types of nonlinear loads considered. This paper presents the application of fractal analysis for analyzing the various harmonic current waveforms generated by typical nonlinear loads such as personal computers, fluorescent lights, UPS, oscilloscope, monitor and laser jet printer. The fractal technique provides both time and spectral information of the nonlinear load harmonic patterns. The analysis results shows that the various harmonic current waveforms can be easily identified from the characteristics of the fractal features. This investigation proves that the fractal technique is useful tool for identifying harmonic current waveforms and forms a basis towards the development of the harmonic load recognition system.