Transmission Investment and Expansion Planning for Systems With High-Temperature Superconducting Cables

Growing electric power demand in densely populated metropolitan areas presents problems due to the lack of availability of space to build transmission lines and due to short-circuit current limits. One of the solutions to meet the increasing demand is high-temperature superconducting (HTS) cables, which have a sufficiently high capacity and can be installed in the limited space of existing ducts. However, since the characteristics of low-impedance HTS cables result in higher system short-circuit levels, fault current limiter (FCL) HTS cables have been developed to solve the fault current problem without an upgrade of the rating of the existing circuit breakers, which is typically necessary when new power facilities in the power system are installed. This paper investigates the impacts of the installation of HTS cables on optimal transmission expansion planning (TEP). A three-stage TEP framework (identification, system analysis, and optimization) is proposed to select between plain HTS or FCL-HTS cables, and to determine the locations of new transmission expansion lines. The TEP optimization problem is formulated using mixed integer linear programming with the big-M method. The simulation results showed that the benefits of installing the FCL-HTS cable can justify their high installation costs.