NEW APPROACH FOR CLASSIFYING TRANSIENT PHENOMENA IN POWER TRANSFORMER USING DISCRETE WAVELET TRANSFORMS (DWT) AND FUZZY LOGIC

Abstract

The role of a power transfonner relay is impact and restraints operate in the cases ofdifferent transient phenomena. This paper presents a new approach for classifYing transientphenomena in power transformer. The discrimination among internal faults, external faults,inrush currents and over-excitation is achieved by the combination of discrete wavelettransfonns (DWT) and fuzzy logic analysis [I - 3].First, the analyzed data are obtained from simulations abnonnal operating cases such asexternal faults, internal short circuit faults, magnetizing inrush by using ATP - EMTP. Next, thesignals are analyzed by discrete wavelet transfonns (DWT) and using detection methods basedon direct recognition of the wave shape distortion of DWT detail (high frequency). Finally, theresults are brought in fuzzy logic system for the recognition of the transient phenomena in powertransfonner. All codes are programmed by Matlab 6.5 compiler. The paper shows, the waveshape distortion is difference in different cases that is favorable condition for recognizing of thetransient phenomena in power transfonner.