Fast identification of redundant transmission capacity constraints with changeable power and load injections

Line flow constraints or transmission capacity constraints are among the most important constraints in power systems generation scheduling and system reliability evaluation problems. For real world systems, there are usually a very large number of transmission capacity constraints and this is one of the main difficulties in solving the related problems. However, it has been found that many of the transmission capacity constraints are redundant, i.e., feasible region and optimal solution of the related problem will not be changed if the redundant constraints are eliminated from the problem formulation. The solution efficiency of any method, whereas, will be greatly improved when the redundant constraints are removed. Approaches for identifying the redundant constraints have been reported in literature and a revised method is established in this paper. The new method can be used to quickly identify the redundant constraints in systems with changeable power and load injections. Compared with the reported methods, the new method is much easier to be understood and implemented. Numerical testing is performed and it is found that the new method is efficient.