Reliability evaluation of bulk power systems

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, i.e., the bulk power system, concepts and models for reliability analysis are not as well established as they are for the generation or distribution systems. In this dissertation, two techniques are developed for computing the reliability indices such as probability of system failure for bulk power systems. The first method is based on the concept that a tie set (path set) represents a set of system states. The use of tie sets in representing sets of system states has a remarkable effect on the computational time required for the solution and produces a mathematically and computationally tractable method. A computer program has been developed to implement this method on a DEC VAX 11/785 computer. The performance of the method is analysed with respect to the reliability of transmission lines as well as the magnitude of system load; examples are given to demonstrate this technique. The second approach is based on delta-star and/or star-delta transformations. This method is presented for calculating the maximum network flow between a pair of nodes. Methodology for the reliability evaluation of a flow network using this approach is described and illustrated.