Reliability Evaluation of an Electric Power System Utilizing Fault-Tree Analysis

Abstract

Abstract. As a large and complex system, an electric power system may be subject to a number of disturbances which can cause full or partial failure in its operation. This premise warrants the inclusion of reliability evaluation in the planning process of a power system. Among the several available reliability evaluation techniques, fault-tree analysis is definitely considered a highly suitable one, particularly for dealing with the inherent complexity of power systems. This paper applies of fault-tree analysis for a partial reliability evaluation of a specific power system known as the Roy Billinton Test System (RBTS). The proposed study is to calculate the reliability of power delivery to the largest load point of the RBTS. The steps carried out in the analysis include fault-tree construction, qualitative analysis by establishing the minimal cutsets, and quantitative analysis by calculating reliability utilizing the data of failure probability of each component of the system. The results presented in this study include failure probabilities for the minimal cutsets, failure probability of power delivery to the system’s largest load and the corresponding reliability, as well as the importance measures of various components. The analysis produces a set of twenty minimal cutsets for the power delivery to the largest load point in the RBTS, with a corresponding numerical value of 0.999597 of system partial reliability for the assumed component reliabilities. The importance analyses utilizing Fussell-Vesely importance, risk achievement worth, and risk reduction worth finds that BUS3 is the most important system component for the power delivery to the largest load, while transmission line L5 is the least important system component.