Assessment of Cable Degradation Using Reflectometry-Based Dielectric Loss Estimation

The lifespan of a cable is intricately linked to the integrity of its insulation. Degradation of cable insulation may result from defects in manufacturing and installation, prolonged thermal aging, and physical damage caused by abrasion, compression, bending, and other external influences. Consequently, the imperative for diagnostic measures becomes undeniable, aimed at assessing overall impacts on cable conditions to ensure the safety and reliability of the cable system's operation. We propose a cable degradation assessment method using the propagation constant and dielectric loss of the cable, based on reflectometry with multivariate objective optimization. This methodology enables the estimation of attenuation and phase shift corresponding to the cable insulation, facilitating precise overall integrity evaluation of cable insulation due to prolonged use. The proposed algorithm utilizes low-voltage and high-frequency signals, unlike conventional high-voltage cable dielectric loss tests. This minimizes the size of diagnostic equipment, advantageous for field applications. Various experiments were conducted to validate the proposed algorithm by estimating propagation constants and dielectric losses, and the results were compared with those from alternative diagnostic techniques.