As the electric power demand increases, power systems become larger and more complicated, and the dependence on electric power has ever been increasing. Power outages will have more social and economic influences. It is very important that we grasp the state of pot-ver systems and operate the power systems stably. Therefore, preventive control will be more desired in power system operations. In this paper we propose a generation rescheduling method for transient stability to solve this problem. At First, using the contingency screening we select severe contingencies for transient stability. If severe contingencies are found, we compute the kinetic energy change at the fault clearing time. Using this information and the linear relationship between the critical clearing time and the generator output at the faulted bus for the critical contingency, we determine the ratio of the generation rescheduling. The proposed method is demonstrated using a sample 4 machine 7 bus system.
