A risk-based planning method for N-1-1 contingency analysis of transmission systems

A risk-based method is introduced for assessing the transient stability characteristics of electric power systems under N-1-1 contingency analysis. It is shown that the risk and corresponding severity depend on factors including the pre-fault load-flow, the clearing time of circuit breakers and the timing of the second fault. To illustrate the assessment of transient stability of a power system, the method is applied to 68-bus, 16-machine IEEE benchmark system. Simulation results using MATLAB-Simulink with repeated random trials are included to confirm the effectiveness of the proposed method for a statistically large set of sample cases.