A practical probabilistic reliability assessment using contingency simulation

This paper describes a practical method of probabilistic reliability assessment (PRA) for large interconnected power systems. It takes a large number of contingency load flow simulations and combine them with a practical method of characterizing the effect of the availabilities of generators, lines and transformers for computing meaningful probabilistic reliability indices (PRI). The method was demonstrated on the US Eastern interconnection and has been applied by several utilities belonging to the EPRI PRA user group. The ability of the method to provide insights on root causes, weak points and regional causes and effects was shown. Results would also be useful for developing effective remedial actions or investment options. The reliability indices could be used for measuring or monitoring bottlenecks, if an online computation of these indices is implemented. They can also be used as one of several performance indices for transmission investment decisions.