Security-constrained transmission switching with voltage constraints

Transmission switching (TS) would play a vital role in the security and economics of electric power systems. The application of TS to the AC model of security-constrained unit commitment (SCUC) for the day-ahead scheduling is presented in this paper. The proposed AC model of SCUC with TS would include real and reactive power flow constraints which increase the controllability of base case and contingency solutions with voltage constraints. A general FACTS model is introduced for the reactive power management in SCUC which is based on the power injection model (PIM). A modified Newton–Raphson power flow model is introduced in the proposed SCUC with TS in which line flows are considered as variables. The proposed AC network model is compared with the DC network model for enhancing the power network controllability and minimizing the operation cost. The case studies exhibit the effectiveness of the TS application to SCUC with AC network constraints.

► Transmission switching is incorporated in the SCUC problem formulation.
► AC power network model considers reactive power and voltage constraints.
► A general FACTS model is introduced for the reactive power management.
► The day-ahead schedule is enhanced by utilizing transmission switching.
► Operating cost will increase as hourly schedule represents more practical solutions.