Reliability evaluation of distribution systems with non-exponential down times

This paper describes an analytical technique and a Monte Carlo simulation approach for determining the reliability indices of distribution systems. The proposed analytical method is based on the 'device of stages' technique so that the impact of equipment aging can be incorporated into the model. Two types of stage configurations are described. For each configuration, the parameters of their probability density functions are estimated using the method of matching moments. The Monte Carlo simulation approach utilizes the component state duration sampling method. A computer program has been developed to implement these methods. The application of the concepts presented in the paper are illustrated by the analysis of a practical configuration.