Sensitivities of multi-area reliability indices with respect to variations of equipment failure and repair rates—An analytical approach

Abstract

This paper describes a methodology for calculating the exact sensitivity of multi-area reliability indices such as LOLP, EPNS and LOLF with respect to variations in equipment failure and repair rates. The system is initially decomposed into “failure modes”, which are then analytically integrated to simultaneously produce the reliability indices and their sensitivities. The methodology is easy to implement on existing reliability evaluation programs and the required additional computational effort is modest. The proposed methodology is illustrated in case studies with a 5-area and 255-generator Brazilian Southeastern system, and the results are discussed. These sensitivities allow ranking equipments in terms of their effect on system reliability indices, as well as estimating the impact of parameter uncertainty on reliability indices.