A Novel Approach to the Classification of the Transient Phenomena in Power Transformers Using Combined Wavelet Transform and Neural Network

The wavelet transform is a powerful tool in the analysis of the power transformer transient phenomena because of its ability to extract information from the transient signals simultaneously in both the time and frequency domain. This paper presents a novel technique for accurate discrimination between an intemal fault and a magnetizing inrush current in the power transformer by combining wavelet transforms with neural networks. The wavelet transform is first applied to decompose the differential current signals of the power transformer into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to train a neural network to discriminate an intemal fault from the magnetizing inrush current. The simulated results presented clearly show that the proposed technique can accurately discriminate between an intemal fault and a magnetizing inrush current in power transformer protection.