Hybrid time-frequency domain of analysis on power quality disturbances

Power quality disturbance imposes problems to the reliability of electrical distribution system. Traditional method of detecting these disturbances by using Fast Fourier Transformation (FFT) has drawback of limitation for detection of stationary disturbances only. Wavelet Packet Transform (WPT) is commonly used to detect the non-stationary disturbances but the exact frequency content cannot be seen. In this paper, a hybrid time-frequency approach is envisaged to reserve the respective domain information. Simulation results show that the intrinsic problem of FFT and WPT is resolved.