In a practical power system

probabilities of some high level outage states may be larger than those of some low level outage states according to the various outage probabilities of system components. The number of these high level outages with relatively large probabilities can be very large and hence their impact on system reliability can be of great significance. However

only credible system states up to a certain contingency level are usually investigated when the enumeration technique used in the reliability evaluation of power systems. These high level outages with large probabilities will be ignored. The problem can be solved by the fast sorting technique considering multistate component models proposed in this paper. Based on the component outage state sequence and the neighboring system states

the technique can quickly select the required number of the system states in descending probability order. The calculation efficiency for state selection by using the proposed technique is much higher than the direct search method. Equally important

merely a quite small number of system states are required to achieve the relatively high evaluation accuracy by using the proposed technique since the high level outage states with large probabilities are selected. Eventually

the merit of the proposed technique is validated by its application to IEEERTS.