Cable Fault Double-Ended Ranging Algorithm Based on Improved Wavelet Threshold Denoising and TT Transform

To address the problem of large errors in single-end fault ranging for distribution cables, this paper proposes an offline double-end ranging method based on improved wavelet threshold denoising combined with the TT transform. First, the propagation characteristics of current and voltage traveling waves are theoretically analyzed. A traveling wave measurement method utilizing a secondary current coupler and a differential capacitive voltage divider is proposed, and evaluate sensor transmission performance within the concentrated frequency band of fault traveling wave signals. Second, signals containing noise are denoised using the improved wavelet threshold denoising algorithm. Subsequently, the TT transform is utilized to calibrate the initial arrival moment of the faulty traveling wave, thus realizing double-ended fault ranging. Finally, an ATP-EMTP flashover discharge model was established, and field tests were carried out for validation. The simulation and test results indicate that under various operating conditions, the double-ended distance measurement method is not influenced by the reflected pulse at the fault point and achieves higher measurement accuracy compared to the single-ended distance measurement method.