Effect of Restricted Repair on System Reliability Indices

In many power system applications, two of the most practical indices of reliability assessment are the system average failure rate and the average outage duration. This paper illustrates the development of these indices for two dissimilar units connected in series and in parallel. The equations for a restricted repair condition are developed using the frequency and duration approach and compared with the known results for unrestricted repair. The only parameter which is appreciably affected by restricted repair is the average system outage duration when the two units operate in parallel. This paper develops an approximate and simple expression to evaluate this parameter which provides results that are very close to those obtained by the complete equation.