Selection of optimal transmission voltage level/technology for the Saudi Arabian transmission grid

This paper reports the findings of a study aimed to investigate the feasibility of introducing AC-500 kV and AC-725 kV extra high voltage transmission and expanding the utilization of 500/600 kV HVDC technology, for future bulk power transmission between major areas on the SEC network. The three transmission alternatives were compared against the present operating voltage of 380 kV. The authors used SEC transmission planning bases and criteria for performing this study, which includes steady-state and dynamic performance criteria, selection of conductors for different voltage levels and technology, the cost estimate for the transmission elements and the economic parameters. Initially, a technical analysis was conducted on 2020, 2024, and 2030 base cases to validate whether the existing and the new 380 kV interties proposed by SEC are sufficient to achieve the required power transfer levels between the various operating areas. Further analysis was carried out to determine the feasibility of shifting the generation (thermal and renewables) from COA to EOA and WOA. Once the validity of the base case scenarios was investigated, the techno-economic feasibility of introducing HVDC, AC 500 kV, and/or AC 725 kV, was studied for years 2024 and 2030 and for different generation siting scenarios. These generation scenarios assumed generation displacements from the central operating area to the neighboring coastal areas. In the final analysis, the study allowed to find the most techno-economically viable option for each generation scenario.