Detection and measurement of power quality disturbances using wavelet transform

This paper deals with the use of a continuous wavelet transform to detect a nd analyze voltage sags and transients. A recursive algorithm is used and i mproved to compute the time-frequency plane of these electrical disturbance s. Characteristics of investigated signals are measured on a time-frequency plane. A comparison between measured characteristics and benchmark values detects the presence of disturbances in analyzed signals and characterizes the type of disturbances. Duration and magnitude of voltage sags are measur ed, transients are located in the width of the signal, Furthermore, meaning ful time and frequency components of transients are measured. The whole met hod is implemented and tested over a sample representing recorded disturban ces. Detection and measurement results are compared using classical methods .