Preventive control actions for enhancing the transient stability of power system ensures the system stability under a given contingency. Generation rescheduling through stability constrained optimal power flow (TSC-OPF) is one of the widely adopted preventive control scheme. This study reports an approach for enhancement of transient stability using global transient stability constrained optimal power flow (TSC-OPF) methods. The proposed approach uses individual machine equal area criterion

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... ework (IMEAC), which is a direct time-domain approach for transient stability analysis, to carry out two important functional aspects of TSC-OPF methods: first, individual machine Kimbark curves (IMKC) are used to perform the transient stability analysis; second, IMKC around the critical clearing time (CCT) are used to identify most severely disturbed machines (MDM) for the given contingency. Further, the critical trajectories of these MDMs are utilized in forming reference transient stability constraints, at only one particular time step of integration. In such manner, transient stability constraints are modified at each iteration of TSC-OPF, so that they represent the dynamic response of the power system efficiently, while operating condition is improving through TSC-OPF iterations. Numerical examples demonstrate the effectiveness and main properties of the proposed approach. INDEX TERMS Critical trajectory, dynamic liberation point, individual machine Kimbark curve, leading loss of synchronism point, most severely disturbed machines, transient stability constraints, transient stability constrained optimal power flow.