A decomposition method to calculate available transfer capability of large interconnected power grid

To cope with the unbalanced distribution of energy sources among regional power grids, it is necessary to implement large-capacity long-distance electric power transmission form large energy base, so it is very necessary to calculate the available transfer capability (ATC) of large interconnected power grid, however, the ATC of large interconnected power grid cannot be directly calculated due to the difficulty in the collection of complete data. In allusion to this problem, a decomposition method to calculate ATC of large interconnected power grid is proposed, and it basic principle are as following: according to natural partition a large interconnected power grid can be divided into several subsystems and their ATCs can be directly calculated, and then according to the connections in series or in parallel among subsystems and based on the calculated ATCs of these subsystems the ATC of large interconnected power grid can be indirectly calculated. The calculation model of probabilistic ATC and the calculation model of ATC under deterministic connection in series and in parallel are established respectively; when the ATC of a certain subsystem is calculated, the idea of Ward equivalent is applied to make other subsystems equivalent, thus the complex connections among subsystems can be effectively dealt with. The correctness of the proposed calculation principle and the feasibility of the adopted calculation method are verified by results of calculation examples.