State extension for adequacy evaluation of composite power systems-applications

It is not feasible or even possible to investigate all the possible system states of a large practical composite generation and transmission system, as the number of the system states can be extremely large. The probabilities of the normally uninvestigated high level system outage states are individually very small, but the total value can be significant to the large number of these states. The state extension algorithm can efficiently extend the knowledge of the investigated system states to collectively include the effects of a large number of the uninvestigated system states. The accuracy of the adequacy indices, when using the state extension technique, is therefore improved without investigating the high level system states individually, which requires very large computation times. This paper illustrates the effectiveness of the state extension algorithm by application to two reliability test systems, the RBTS and the IEEE-RTS.