Defect Location and Identification Method for Long-Distance Cable Based on Frequency Modulated Continuous Wave

Conventional frequency domain reflectometry faces challenges in detecting local defects for long-distance cables, such as weak anti-interference capability, large shielding zone, and inability to identify defect types. To address these issues, a method for defect location and identification based on frequency modulated continuous wave is proposed in this paper. Firstly, the principle of defect location is introduced, where the wave is injected into the cable head, and the beat signal carrying the information of defect location and characteristics is obtained. Secondly, the diagnostic function for local defects is constructed utilizing the generalized orthogonal integration algorithm, and the identification criterion for defect types is proposed based on the diagnostic waveforms. The position of the diagnostic peak is used for defect location, and the polarity of that is used for type recognition. Finally, the effectiveness of the proposed method is verified by simulation and experimentation. The results indicate that the method can accurately locate the local defect, with a relative location error of less than 0.3%, and the criterion can efficiently identify the defect types.