Industrial Applications of Cable Diagnostics and Monitoring Cables via Time–Frequency Domain Reflectometry

The demand for cable diagnostics and monitoring techniques has increased significantly in recent decades. Various diagnostic tests such as partial discharge, dielectric loss, and elongation-at-break tests are available in real-world applications. Among the cable diagnostic methods, reflectometry can be used to detect the location of a fault according to the reflected signal at the impedance-discontinuity point. Because it is a nondestructive method and can be applied regardless of the cable type, reflectometry is commonly used for monitoring real-world applications. Time-frequency domain reflectometry, an improved type of reflectometry, is more accurate than conventional reflectometry and employs time-frequency localized signals that are robust to noise. To compensate for the errors occurring in the time-frequency domain reflectometry, several algorithms have been reviewed. In the past, because the signal of time-frequency domain reflectometry contains both time and frequency information, a high-specification signal generator and measurement sensors were required, which made practical application of the method difficult. However, with recent developments in instrumentation and sensing technology, reduction in the instrumentation size and cost facilitates the use of time-frequency domain reflectometry in various industrial applications, e.g., control and instrumentation cables in nuclear power plants, superconducting cables, and submarine cables. This work reviews the use of time-frequency domain reflectometry for cable diagnostics and monitoring in real-world applications. The purpose and results of the experiments on industrial applications are introduced and analyzed. This study also suggests directions for further research to make time-frequency domain reflectometry a diagnostic standard.