Time-frequency transforms comparison for power quality analysis

Voltage signal contains transient disturbances that are caused for multiple reasons. One way to improve the power quality is to analyze efficiently and to deeply understand these signals. The most typical disturbances in power quality have been generated in order to analyze by time-frequency transforms: wavelet transforms (WT) and S-transform (ST). Thus can be obtained a comparison of results of these time-frequency transforms. The voltage signals with different disturbances are simulated by Matlab code with 128 samples per cycle. The disturbances used in this work are carried out from standards, as voltage sag, voltage swell, short interruptions and harmonic distortion, in addition to other disturbances of transitory order as spikes, notches and oscillatory transients.