An analytical technique for bulk power system reliability evaluation

Abstract

The increasing size and complexity of power systems, coupled with present day financial constraints, have made the use of probabilistic methods and reliability indices a necessity in order to maintain the continuity and quality of service to customers. For the combined generation and transmission system, that is, the bulk power system, concepts and models for reliability analysis are not as well established as they are for the generation or distribution systems. This paper presents a technique based on tie sets for computing the reliability indices such as probability of system failure for bulk power systems. The power system network is modelled as a transportation network so that the constraints on the real power flow in each line of the network are observed. The problem of bulk power system transmission reliability is then viewed as a reliability evaluation of a multinode capacitative network. A path set is defined to be the paths or combination of paths from the input node to the output node of a power system network such that the total system load is satisfied. In this method an upper bound to the probability of system failure is computed. A computer program has been developed to implement this method on a (DEC) VAX 11/785 computer. The performance of the method is analyzed with respect to the reliability of transmission lines as well as the magnitude of the system load.