A novel method for evaluating future power distribution system reliability

The reliability assessment of future distribution networks is an important subject due to the increasing demand for more reliable service with a lower frequency and duration of interruption. The connection of future distribution networks may not be simple radial circuits and analyzing the reliability of such a network is usually complicated and time consuming. In this paper, a technical approach for evaluating the reliability of a networked distribution system is described. The proposed algorithm is based on the identification of circuit minimal tie sets using the concept of Petri nets. Prime number encoding and unique prime factorization are then applied to classify the remaining combinations as tie sets, cut sets, or minimal cut sets. A Markov model is used to compute the availability and failure frequency of the network. A well-known test bed [the Roy Billinton Test System (RBTS)] is used to illustrate the analysis and calculate different load and system reliability indices, including SAIFI and SAIDI. The method shown is algorithmic and appears suitable for offline comparisons of alternative secondary distribution system designs on the basis of their reliability.