A Iterative Method to Optimize Tie-line Exchange Power Based on Marginal Power Generation Cost

To make fully use of power transmission capacities of the tie-lines and reduce the total operating costs of the power grid, a marginal power generation cost based iterative optimization is proposed to optimize exchange power of the tie-lines. The proposed methodology iteratively optimizes exchange power of the tie-lines, starting from initial operation states of each regional power grid and initial exchange power of each tie-line without changing the results of unit commitment. The method can be easily applicated to engineering practice because it is closely related to the actual dispatching process of the power grid, and only requires information of the marginal unit operation in each regional power grid, protecting the data privacy of each regional power grid. Finally, a simulation is performed based on a case system of three regional grids and three tie-lines, and the simulation results verify the method.