Network-Constrained Unit Commitment Incorporating Dynamic Thermal Rating and Transmission Line Switching

Abstract

The increasing penetration levels and stochastic characteristics of renewable energies and aging of transmission equipment bring potential negative impact on the economic and reliable operation of power grid. Therefore, the realistic and cost-effective choice for the utilities is to tap the potential of existing transmission infrastructures. Some smart grid technologies can leverage the potential transmission capacity and offer a flexible way for the power system operation. The dynamic thermal rating can evaluate the maximum transmission capacity of lines dynamically based on the environmental data. The optimal transmission switching can change the transmission topology and remove the transmission congestions. These technologies should be considered in the network-constrained unit commitment problem systematically to study their impact on the power system scheduling. However, the dynamic thermal rating incorporated network-constrained unit commitment studies are all based on the fixed transmission topology. So the overall influence of dynamic thermal rating and transmission line switching on network-constrained unit commitment has not been studied as yet. In this paper, the line switching technology and dynamic line rating according to multi-regional environmental information are incorporated in the network-constrained unit commitment framework. Case studies are implemented on a modified RTS-79 system. The simulation results verify the effectiveness of the coordination of two technologies in the reduction of generation cost and wind curtailment.