Power Transformer Faults: Analysis, Classification and Protection

With the increase in power consumption, the safety of the power transformers has increased manifolds. Ideally, there should be a no-fault operation of power transformer which is yet to be achieved. The objective of this paper is to provide a complete protection scheme of power transformers. The faults are analysed and classified using Discrete Fourier Transform (DFT) and Wavelet Transform. The DFT based controller is used to detect inrush and fault currents. We have used wavelet transform and it has proven to be a very effective tool for detailed analysis of these transients. In addition, Fuzzy logic controller, with minimal computational complexity, is implemented for the differentiation of inrush, internal and external faults using the detailed coefficients obtained by wavelet analysis providing successful classification. On the basis of the obtained coefficients, we have developed a Rapid Prototype of FFT based algorithm on differential protection scheme of the transformer providing the speed between 1-15 msec as compared to 100msec as per the standards of IEEE. The obtained results show that our proposed approach is rapid and could protect the power transformer from faults with accuracy.