Using probability distribution functions in reliability analyses

The use of probability distributions to describe reliability inputs such as failure rates and restoration times is fairly new compared to using average values for parameters. Predictive indices of composite power system reliability are frequently calculated but not directly used in the decision-making process, possibly because the indices are usually described using average values and convey little information about risk. More information can be derived and a different impression given by indices of a reliability analysis when probability distributions are used to describe the inputs and outputs, as shown in examples presented in this paper.