Abstract: Developing large-scale renewable energy bases is one of the key tasks in the national 14th Five-Year Plan of modern energy systems. Aiming at transmitting large-scale hydropower and photovoltaic power in southeast Tibet, considering the high altitude of the energy base and the limited transmission corridor, we design the topologies of the ±800 kV/10 000 MW heterogeneous serial high voltage direct current (HVDC) transmission system, the four-terminal modular multilevel converter (MMC) based HVDC system with multiple DC voltage levels, and the four-terminal hybrid HVDC, respectively. Aiming at transmitting wind power and photovoltaic power in the desert, barren and Gobi areas, we propose the ±800 kV/10 000 MW three-terminal MMC-HVDC system, four-terminal MMC-HVDC system, and heterogeneous serial HVDC system with multiple DC voltage levels. Finally, the simulation models of each topology are built using PSCAD/EMTDC. And the technical characteristics of each topology are compared and analyzed. The research of this paper may provide a reference for the topology design of related engineering practices in the future.