Cable Soft Fault Detection via Frequency Reflectometry
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Solution Overview
Problem
Conventional cable diagnostic methods, such as time and frequency reflectometry, are ineffective in detecting soft faults in cables, which result from surface degradation, friction, or heating, as these faults generate low-amplitude peaks that are difficult to detect during normal operation without disrupting the cable's operation.
Innovation Solution
A reflectometry method that calculates the attenuation of a signal propagating along the cable to enhance the detection of soft faults by transforming frequency domain parameters into the time domain, identifying amplitude peaks, and comparing them with predetermined thresholds to locate and monitor faults over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional time or frequency reflectometry methods are used to detect clear faults in cables, then the detection of significant local impedance modifications is effective, but soft faults generating low amplitude peaks remain undetected
Solution Approach 1:
The patent transforms the reflectometry signal from time domain to frequency domain using Fourier transform, then applies spectral analysis to detect soft faults. By changing the domain of analysis from temporal to spectral, the method reveals frequency characteristics that amplify the visibility of soft fault peaks, enabling detection of impedance modifications too subtle for conventional time-domain methods
Solution Approach 2:
The invention adds a frequency dimension to the analysis by transforming the one-dimensional time-domain reflectogram into a two-dimensional frequency-time representation. This dimensional expansion allows simultaneous observation of multiple frequency components, making soft faults detectable through their characteristic frequency signatures rather than relying solely on amplitude thresholds
2Measurement precision
If LIRA reflectometry method with frequency variation is used to detect soft faults, then phase shift measurement enables soft fault detection, but cable operation must be interrupted for testing
Solution Approach 1:
The patent enables continuous cable operation during diagnostics by using frequency reflectometry with spectral analysis instead of time-domain methods that require signal injection interruptions. The method processes reflected signals in the frequency domain, allowing detection of soft faults through phase and amplitude spectral characteristics without requiring complete operational shutdowns
Solution Approach 2:
The invention introduces frequency domain transformation as an intermediary processing step between signal injection and fault detection. By applying Fourier transform and spectral analysis as intermediate operations, the system extracts fault information from continuously available reflected signals, eliminating the need to interrupt cable operation for testing
3Measurement precision
If frequency reflectometry is used to characterize soft faults, then the method can detect low amplitude peaks, but it cannot operate simultaneously with normal cable operation
Solution Approach 1:
The patent employs dynamic frequency sweeping where the test signal frequency is continuously varied over time while the cable operates normally. This dynamic approach allows the system to track impedance variations along the cable in real-time, characterizing soft faults through their frequency-dependent response without disrupting operational signals
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable detection and location of soft faults without interrupting cable operation, improving fault detection sensitivity and allowing for real-time monitoring of fault evolution.
Implementation Method 1
a step of estimating a parameter characteristic of the propagation of a signal propagating in said cable, among which the attenuation α(f), the phase factor β(f)
Implementation Method 2
a step of identifying the faults impacting the said cable from the identification of the amplitude peaks of the estimate of said transformed parameter in the time domain
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The invention relates to a reflectometry method for identifying at least one fault affecting a cable in at least one place, characterized in that it comprises the following steps: - A step (302) for estimating a characteristic parameter of the propagation of a signal propagating in said cable, among the attenuation α(f), the phase factor β(f), the reflection coefficient Γin(f) at the input of the cable or a linear or non-linear function of any one of these parameters or a combination of several of these parameters, said estimate being made based on the frequency of said signal from a reflectogram of said signal, - A step (303) for transforming the estimate of said parameter from the frequency domain to the time domain, - A step (305, 306) for identifying faults affecting said cable from the identification of the amplitude peaks of the estimate of said parameter transformed in the time domain.