INVESTIGATION OF POWER SYSTEM TRANSIENT DISTURBANCES IN FREQUENCY AND TIME-FREQUENCY DOMAINS

Abstract

Switching transients are defined as high frequency disturbances in power systems. These events are the important part of the power quality problems. In this study, to determine these transient disturbances, Autoregressive-Burg and Eigenvector techniques are used to obtain power spectral densities on frequency domain and the obtained results are compared. In these frequency domain techniques frequencies of the transient disturbances are defined clearly but the time of the disturbances can't be shown. Time-frequency domain analysis techniques are used in order to show both the frequency and time of the transient disturbances. For this aim, in this study Short time Fourier transforms (STFT) is employed for time-frequency domain analysis of switching transients. Proposed methods separate the frequency components of original signals accurately. Eigenvector and Burg methods have been employed to make a comparison in frequency domain analysis. It can be concluded that Eigenvector method gives a better frequency resolution with sharper frequency peaks.