A new paradigm for impulse testing of power transformers

Reliable methods for sensitive detection of internal defects in the insulation system of a power transformer during impulse test, are still an active area of research. A new impulse analysing system for a power transformer is discussed. It is based on recognising the possible nature of winding fault using the temporal records, transfer function and high frequency spectra. The neutral current, transferred surge current, capacitively transferred current, could be analyzed using these approaches. But for the analysis of interturn discharges and occurrence of partial discharges which are fast decaying signals it has been observed that application of the wavelet transforms would be more appropriate. This paper discusses methods of analyzing some of the winding faults using signal processing methods.