Detection and localization of inter-turn fault in the HV winding of a power transformer using wavelets [Comments and authors' reply]

We discuss the paper by M.R. Rao and B.P. Singh (ibid. vol. 8, pp. 652-567, 2001) describing a wavelet approach for identification and localization of "minor" or "small" faults within HV transformer windings during lightning impulse tests on them. Although the authors' claim appear to be impressive, there are serious questions regarding the circuit models and computational procedures used, as well as, in the interpretation of the results obtained from the wavelet method. Therefore, the following is intended to obtain clarification from the authors and to help the reader with the usage of wavelets in addressing such problems.