A new wavelet and fuzzy based power quality index for distribution systems under stationary and nonstationary disturbances

摘要

The evaluation of power quality is needed due to the prolification of disturbing loads in the electric power systems. In the past few years there has been an increase of the distortion level in distribution systems due to the development of non linear loads. In this paper a novel power quality index has been introduced which can evaluate the power quality under stationary and nonstationary disturbances Three power system components has been considered, representative quality power factor, detail pollution factor and standard deviation of the signal for the development of the new power quality index. The proposed power quality index has been applied to different cases, sinusoidal, non sinusoidal, linear, non linear, stationary and non stationary waveforms. It has been found that new power quality index can completely characterize the power system disturbances both qualitatively and quantitatively.