Security constrained unit commitment with dynamic thermal line rating

The integration of the Dynamic Line Rating (DLR) of Overhead Transmission Lines (OTLs) in power systems Security Constrained Unit Commitment (SCUC) potentially enhances the overall system security as well as its technical/economic performances. This paper proposes a scalable and computationally efficient approach aimed at integrating the DLR in SCUC problem. The paper analyses the case of the SCUC with AC load flow constraints. The AC-Optimal Power Flow (AC-OPF) is linearized and incorporated into the problem. The proposed multi-period formulation takes into account a realistic model to represent the different terms appearing in the Heat-Balance Equation (HBE) of the OTL conductors. In order to include the HBE in the OPF, a relaxation is proposed for the heat gain associated to resistive losses while the inclusion of linear approximations are investigated for both of convection and radiation heat losses. A decomposition process relying on the Benders decomposition is used in order to breakdown the problem and incorporate a set of contingencies representing both generators and line outages. The effects of different linearization as well as time step discretization of HBE, are investigated. The scalability of the proposed method is verified using IEEE 118-bus test system.