WAVELETS AND ITS APPLICATIONS OF POWER SYSTEM PROTECTION

Abstract

ABSTRACT In this work, a new digital protection algorithm is developed for the power transformer which is the most important and expensive element in a power system. Due to their different sizes and varieties, relaying for power transformers differs from situation to situation. Transformer protection algorithms, that have been developed so far, have proved their efficiency and computational ability. Using several windowing techniques cause significant delay for relay operation. Due to increasing power quality standards such as IEEE 519, new high performance algorithms are needed. For this purpose, the wavelet technique is introduced and used for analyzing magnetizing inrush currents and faults current. Wavelets introduce new classes of basis functions for time – frequency signal analysis and have properties particularly suited to the transient components and discontinuities evident in power system disturbances. For this reason, the wavelet technique and transformation were used and very accurate and satisfactory results were obtained in the time domain. As it is stated in Section 3, it is observed that magnetizing inrush, rated condition and fault conditions are easily distinguished by using high frequency components. Keywords: Wavelet Technique, Transformer Protection, Digital Protection