This paper quantifies and discusses the increase in induced voltage on a sheath due to changes in duct banks in terms of type and dimensions along an underground transmission line, guaranteeing the ampacity required for a project. The four most common duct banks in double-circuit underground transmission lines with phase transposition were considered in this study, along with two special cross-bonding techniques: continuous cross-bonding (CCB) and sectionalized cross-bonding (SCB). These techniques aim to reduce sheath currents and enhance the distribution of the induced voltage on the sheath. The analysis considers two distinct scenarios in which the profile of the induced voltage is calculated: the first one accounts for underground obstructions, intersections with important traffic avenues, and ground with high excavation costs that force changes in the duct bank dimensions and configuration, which is the most exact and realistic case. The second one solely considers one typical configuration of a duct bank along the route. This last scenario is normally applied to calculate the induced voltage when an underground transmission design is required. The results show that when installing cables at a greater depth, it is imperative to increase the distance between them to guarantee the ampacity. The induced voltage on the sheath will rise as the distance increases. Furthermore, the results reveal that instead of calculating the induced voltage by considering the scenario that is exact and most like a real case, it is enough to calculate following the second scenario and then add a scaling factor according to each duct bank configuration.

The rising energy consumption in transmission networks has markedly increased the burden on transmission lines, necessitating an expansion in their capacity to accommodate this surge. Consequently, high-temperature low-sag (HTLS) conductors are emerging as substitutes for conventional conductors in recent network upgrades due to their superior power transmission capabilities, especially under elevated temperatures. This paper critically analyzes the feasibility of adopting HTLS conductors over conventional counterparts for future single-circuit overhead transmission lines. Specifically, we evaluate leading HTLS conductors, such as ACCC and ZTACIR, against the conventional AAAC conductor. Following a two-stage methodology, this study presents a comprehensive electromechanical assessment of overhead transmission line. First, ampacity calculations were performed to determine the required conductor cross-sections. Subsequently, mechanical performance was evaluated to quantify structural loads and their impact on tower design. Among the HTLS conductors analyzed, the ACCC exhibited the lowest mechanical loads, indicating a better performance in terms of structural efficiency. ACCC and ZTACIR conductors significantly reduced the weight imposed on transmission towers compared to conventional AAAC, primarily due to their lower tensile forces. Furthermore, our results demonstrate that HTLS conductors present nearly identical electrical parameters across a broad frequency spectrum, conversely to the more variable behavior of conventional alternatives. Based on these results, ACCC conductors are strongly recommended for future projects, pending detailed economic analysis.