A direct method for obtaining critical clearing time for transient stability using critical generator conditions

SUMMARY This paper proposes a new method for transient stability analysis for electric power systems by extending our previous studies. A special feature different from the ordinary existing methods is that a minimization problem is formulated for obtaining critical clearing time for transient stability. The critical trajectory is defined as the trajectory that starts from a point on a fault‐on trajectory at critical clearing time and reaches a critical point of losing synchronism. This paper studies the treatment of the critical condition and then proposes a new formulation for the transient stability problem. It will be demonstrated that the solution of the minimization problem successfully provides the exact critical clearing time that agrees with the conventional numerical simulation method. Copyright © 2011 John Wiley & Sons, Ltd.