An efficient accuracy improvement method for cable defect location based on instantaneous filtering in time-frequency domain

Time-frequency domain reflectometry is a highly sensitive method to locate cable defect. However, the potential defect far from the cable head may not be accurately located because of the signal amplitude attenuation and the interference parts. To solve the problem, this paper proposes an accuracy improvement method based on instantaneous filtering in time–frequency domain. The method extracts the frequency spectrum of the time–frequency signal, and then filters the spectrum and reconstructs the signal based on the difference between the signal and interference spectra, which can eliminate the interference and improve the location accuracy. In the simulation, the location error of this method drops from 5.47 % to 0.57 %. In experiment, the proposed method reduces the location errors and magnifies the location peaks of the breakage defect, thermal aging defect, and ground faults. The method is expected to improve the accuracy of TFDR and help detect potential defect in the future.