Analysis of Induced Voltages and Currents Profiles in Power Cable Metallic Sheaths: Assessing the Effect of Ideal and Non-Ideal Transpositions
Academic Article in Scopus
This paper presents a comparative analysis of the behavior of induced voltage and current in power cable conductive sheaths with ideal and non-ideal cross-bonding under different operating conditions. The methodology involves solving the telegrapher's equations in the space-time frequency domain. A two-dimensional Numerical Inverse Laplace Transform (TNLI-2D) is then applied to obtain voltage and current profiles along the cable length. This approach enables continuous spatial sampling, which helps to identify the location and duration of the most important voltage and current peaks. The results indicate that, in steady-state operation, non-ideal transposition increases circulating currents in some minor sections of the screen, compared to the ideal transposition case. For a real system studied, currents in specific sections were observed to increase by approximately four to six times compared to the ideal scenario. The steady-state voltage distribution remained similar between ideal and non-ideal conditions, with non-ideal sections showing increments no greater than 11% in magnitude. The study also examines cable system behavior during transient conditions, such as faults, in configurations with and without Sheath Voltage Limiters (SVLs). Based on simulation results, under a fault condition, it was observed that the non-ideal transposition of screens does not produce a significant change in the current values difference across the minor sections when compared to the ideal transposition. With this technique, a high-resolution quantification of the spatial-temporal distribution of electrical stresses along the cable screens is possible, enabling identification of where these stresses reach higher levels.
