###### Abstract  
In recent years, the scientific and industrial interest regarding alternative technologies for transmission cables has increased. These conductors should efficiently transmit significant amounts of power between grid nodes, which are expected to be particularly congested due to the projected global increase in electricity production. Superconducting cables are considered a promising solution in this context, offering the potential to transmit large amounts of energy with minimal losses and compact dimensions, thereby potentially benefiting the environment. To evaluate the feasibility of integrating superconducting cables into existing grids, techno-economic approaches should be adopted. Such techniques enable the conceptual design of a specific cable structure, allowing users to explore a wide range of operating parameters to derive optimal designs. This paper reports a comprehensive techno-economic analysis of High Voltage Alternating Current (HVAC) cables realized with High-Temperature Superconducting (HTS) tapes, with the aim to transmit extremely high-power level. The optimal coaxial design is selected using Optimization Tool for Superconducting Cable Research (OSCaR) by implementing a graded approach to the critical current of the HTS tapes used for the different phases. This optimization aims to achieve the most effective balance between the cost of the coated conductors and their electrical properties. The whole set of model equations, the user-defined parameters, and the applied constraints are detailed. The OSCaR tool is then applied to assess the impact on the optimized design of the cable system and the corresponding cost indexes of several crucial parameters, such as the maximum transmitted power, the voltage level, and the line length. High-Temperature Superconductor (HTS); HTS transmission cable; High-Voltage Alternating Current (HVAC) cable; techno-economic assessment (TEA) 2024 2 rise to a series of public and private projects for the design and realization of small-length prototypes of HTS cables, with the aim of also enabling their future adoption for power transmission over long distances. These projects are distributed worldwide, with notable implementations in South Korea [3; 4; 5; 6], Japan [7; 8; 9], China [10; 11], Europe [12; 13; 14; 15; 16], and the USA [17; 18]. In fact, with the foreseen increase in global electricity production over the next few years, grids are expected to face significant congestion, requiring efficient power transmission systems for which advancements in superconducting technologies could provide a valid solution. In this context, various cable designs have been proposed. For example, superconducting cables can be distinguished by considering the mutual position of the electrical insulation and the coolant flow between warm dielectric (insulation placed outside the channel for the cryogenic fluid) and cold dielectric (CD) cables (with insulation contained inside of the cryostat, operating at cryogenic temperatures) [19]. Almost all cable projects proposed nowadays are based on the CD layout as it allows easier access to the cryostat, being electrically insulated from the conductive phases. Furthermore, with reference to AC cables, different configurations can be identified based on the arrangement of the phases and the cryostat. _Single-core_ cables have dedicated cryostats for each of the three phases, while in _three-in-one_ cables, the tapes belonging to each phase are helically wound on three separate axes, and then the phases are contained in a single cryostat. Finally, _coaxial_ cables present the three phases helically co-wound on the same axis and separated by concentric insulating layers [20]. These configurations may be more or less suitable, depending on the operational constraints of the case study. Since no existing production standards for superconducting cables have been established yet, all cable layouts proposed in the literature should be carefully considered in the design phase of new lines or when replacing existing ones.