A comparison analysis of voltage sag and transient using short time fourier transform, wavelet and S-Transform / Fifi Natasya Shaari

This thesis presents a comparison of technique in extracting the features for voltage sag and transients in distribution systems using Short Time Fourier Transform (STFT), Wavelet Transform and S-Transform. Different data of voltage sag and transient are taken from Tenaga Nasional Berhad Distribution (TNB) Malaysia. This data is further analyze using the Matlab. The study features involves specifically in non-stationary signals. Previous tools like Fourier Transform have only frequency resolution resulting a lower level of effectiveness to the disturbance detection procedure. Therefore, a comparison is made between those recent techniques to investigate which techniques can identify the problems interactively when large datasets are applied.