Equal-area criterion: an extension for multimachine power systems

A method of determining the transient stability of a multimachine power system through a modified equal-area criterion is proposed. The method determines the first-swing stability limit of the most severely disturbed machine in the system by comparing two integrals or areas called the accelerating and decelerating areas. Unlike the standard equal-area criterion, the proposed method can be directly applied to a multimachine power system without representing the system by an equivalent single-machine infinite-bus model. The proposed method was tested on three power networks for a number of different faults. The critical clearing time obtained by the proposed method in each case was compared with the actual value found by the step-by-step method.<>