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This paper presents a new method for automatic classification of power quality events, developed based on S-transform. This transform provides high resolution time-frequency representations used to calculate power quality indices. Supplementary information about detected events (the magnitude, duration and frequency spectrum of the identified disturbances) are extracted in order to characterize the...
The Fourier Transform analysis is able to estimate the amplitude and frequency of signals under stationary conditions. For transient or aperiodic signals the Fourier analysis is unable to obtain accurate results and a joint time-frequency analysis must be used to provide simultaneous time and frequency information of transient intervals. A voltage quality index is proposed for evaluation of both the...
Classification for short duration power quality disturbance (SDPQD) is the premise for electric power quality improvement. A new classification method for SDPQDs is proposed in this paper. It is based on partial similarity and scale zooming of the module time-frequency matrix (MTFM) by Stransform. All types of disturbances with different durations are standardized by time-frequency scale zooming....
Power quality has become a great concern to all electricity consumers. Poor power quality can cause equipment failure, data and economical losses. An automated monitoring system is needed to ensure signal quality, reduce diagnostic time and rectify failures. This paper presents the detection and classification of power quality signals using bilinear time-frequency distribution which is smooth-windowed...
The Fourier transform analysis is able to estimate the amplitude and frequency of signals under stationary conditions. For transient or aperiodic signals the Fourier analysis is unable to obtain accurate results and a joint time-frequency analysis must be used to provide simultaneous time and frequency information of transient intervals. A power quality index is proposed for evaluation of both the...
This paper proposes a technique to select a wavelet function that shows good characteristics for the identification of power quality disturbances. It considers the low frequency disturbances such as flicker and harmonics as well as high frequency disturbances such as transient and voltage sags. Due to time-frequency localization properties, the discrete wavelet transform permits signal decomposition...
With the wide application of sensitive power electronic devices in industry, the power quality (PQ) disturbance problems become more concerned. The S-transform is a time-frequency localization technique that bridges the gap between the short-time Fourier transform and wavelet transform. A new PQ disturbances identification method based on S-transform time-frequency analysis and fuzzy expert system...
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