A Bi-level Approach to Transmission Network Planning Considering Operational Flexibility

With a large scale integration of fluctuating wind power, it is imperative to improve the operational flexibility in transmission network planning on the basis of considering system security and economy to achieve the goal of safe wind power consumption and reliable power supply. In this paper, a bi-level transmission network planning model considering operational flexibility is proposed to optimize the solution of transmission lines capacity and new thermal generator to be installed. The upper-level model minimizes the investment cost and the operation cost. The lower-level model calculates the lack of flexibility and loss of load of the system based on the line capacity and installed units from upper layer. Both upper and lower models can be transformed into mixed integer linear programming (MILP) problems. The effectiveness and validity of the proposed method are illustrated on the IEEE-RTS system.