Transient Stability Evaluation of Multimachine Power Systems: A Probabilistic Approach Based Upon the Extended Equal Area Criterion

The stability properties of electrical power systems after a given fault is characterised by means of the instability probability, which is defined in terms of the critical clearing time and the fault clearing time. The probabilistic description of the load demand and its effect on the clearing time is discussed. The method is illustrated with reference to a simple system. The effect of the statistical correlation among the loads on the stability in a multinode system is also analysed.