Fault Diagnosis for Shielded Cables Based on MSST Algorithm and Impedance Polar Plots

Contemporary industries rely on instrumentation and control (I&C) systems to ensure their safe and efficient operation. In particular, shielded cables play a pivotal role in information transmission and signal control within I&C systems. Therefore, the diagnostic techniques of shielded cables for accurately locating faults and assessing their severity are required to ensure the safety and reliability of the I&C systems. This article proposes a new fault diagnosis technique for shielded cables in I&C systems. For fault localization, the multisynchrosqueezing transform (MSST) is introduced to enhance the energy aggregation of the existing localization spectrogram, thus effectively improving the range resolution. For fault severity detection, a novel approach for broadband impedance spectroscopy (BIS) signature interpretation is presented by incorporating the magnitude and phase of the BIS into a polar plot that captures more features of the measured signal than the single magnitude plot. Digital image processing (DIP) techniques are employed to automate the severity detection process. The simulation and experimental results of coaxial shielded cable show that the proposed method can effectively improve the positioning performance and detect the fault severity with relatively little interference from the locations.