## 9 Conclusions
The cable's radial size was reasonably contained in all cases analyzed, varying from 10.7 cm to 12.6 cm for the higher-power case and being significantly smaller than those ones for conventional lines or even other superconducting architectures. The solver suggests using coated conductors with lower electric characteristics (in terms of homogeneity of the critical current along the entire length purchased) for phases realized with more tapes, assuming perfectly balanced AC currents. This occurred for the outermost phases, characterized by a greater number of tapes wound side-by-side over wider circumferences. However, the trend was not linear, with the number of parallel layers increasing stepwise (and thus with a stepwise increase in the number of tapes per phase), such as the doubling of the innermost phase (phase 1) from the 2 GW case to the higher-power cases. Subsequently, a parametric analysis was conducted on a 50 km cable transmitting 2 GW at different voltage and frequency levels taken as the most significant levels in worldwide grids: 115 kV/60 Hz, 132 kV/50 Hz, 150 kV/50 Hz, and 220 kV/50 Hz. As expected, lowering the voltage increased the costs, primarily due to higher expenses for superconducting tapes and managing greater AC losses. The total system costs rose by about 53% when the voltage was nearly halved. Finally, a parametric analysis evaluated the cost-effectiveness of different HVAC transmission line lengths. For a 2 GW cable at 220 kV, considering lengths between 5 km and 100 km resulted in savings of approximately 13% for the longest lines compared with the 5 km reference case. For the specified power level and the user-defined parameters, the tool recommended several intermediate cooling stations spaced between 5 km (corresponding to the minimum distance imposed by the authors for adjacent stations) and 7.1 km apart. The approach proposed in this study enables identification of the applicative scenarios within electricity grids where the use of HTS HVAC cables would be more beneficial, providing valuable insights for the cables design phase as well. The comprehensive methodology described here, which the authors consider to be the most significant contribution of this work, is intended to be applied to other superconducting and conventional cable configurations to identify conditions of potential techno-economic convenience. **Author Contributions:** Conceptualization, A.M., G.A., M.B. ([PERSON]), A.L. and L.C.V. ; Methodology, L.C., S.D.S., F.S. and M.B. ([PERSON]); Formal analysis, A.M., G.A., M.B. ([PERSON]), A.L. and L.C.V. ; Investigation, A.M., L.C., G.A., M.B. ([PERSON]), A.L., L.C.V., S.D.S., F.S. and M.B. ([PERSON]); Data curation, A.M., L.C., G.A., M.B. ([PERSON]), A.L., L.C.V., S.D.S., F.S. and M.B. ([PERSON]); Writing--original draft, A.M.; Writing--review & editing, A.M., L.C., G.A., M.B. ([PERSON]), A.L., L.C.V., S.D.S., F.S. and M.B. ([PERSON]). All authors have read and agreed to the published version of the manuscript. **Funding:** This work has been financed by the Research Fund for the Italian Electrical System under the Three-Year Research Plan 2022-2024 (DM MITE n. 337, 15.09.2022), in compliance with the Decree of 16 April 2018. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author. **Conflicts of Interest:** The authors declare no conflict of interest.