The paper depicts the description of a program for solving the reliability of electric power networks of all voltage levels. As input data reliability data on particular nodes and branches is used; power consumed in each node as well as power carrying capacity in each branch is taken. Then the result is the power balance of the network concerned, the resultant reliability parameters of all nodes and the value of electrical energy probably unsupplied to the nodes. We also further develop advanced model for reliability calculations, based on Weibull failure distribution function. By changing Weibull parameters can be simulated all three stages of units lifecycle-earlytype (infant mortality), chance-type (equal to exponential distribution) and wear-out caused failures.
