Introduction  Safety, reliability and economy of island power supply is an important task in power system planning and design.

  Method  According to an example of power supply planning on the island in the south of China, a comprehensive comparison about feasibility, reliability, investment and price between local gas power development and flexible HVDC connection was introduced based on setting up and solving the integer programming model of the configuration of the gas turbine group.

  Results  The results show that: in order to satisfy the island power demand and take into account the uncertainty of long-term load growth, it is recommended to adopt the hybrid power supply scheme of local gas power and interconnection under feasible technical conditions.

  Conclusion  These methods and results provide a reference for the power system planning and design of other similar islands.