Composite system reliability evaluation using state space pruning

This paper presents a method of computing the reliability indices of a composite generation-transmission system by performing Monte Carlo simulation selectively on those regions of the state space where loss of load states are more likely to occur. These regions are isolated by performing state space decomposition to remove coherent acceptable subspaces. It is shown that this method results in a significant reduction in the number of sampled states, thereby reducing the computational effort required to compute the system and bus indices. The method assumes a DC flow model, and is tested using the IEEE Reliability Test System. The proposed method is not intended to replace existing variance reduction techniques; in fact, such techniques may be used in conjunction with the proposed method to further improve its efficiency.