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This paper focuses on material that is required for the practical application of fuzzy reliability; impacts of repair and data uncertainty. For this purpose, a holistic solution is presented to measure and manage the degree of uncertainty in the reliability indices of repairable systems. First, a flexible form of Markov Processes (MPs) namely Equivalent Transition Rate (ETR) is introduced in order to obtain an analytical formalism. Second, we delve deeply into the issues of fuzzy arithmetic by providing an intuitive, methodic and computational discussion of feasible approaches; Standard Fuzzy Arithmetic (SFA), Intermediate Variables (IMVs) and Taylor Series (TS). Specific emphasis is then placed upon Fuzzy Transformation Method (FTM). Third, we evaluate the performance of proposed techniques in case of a reliability problem involving fuzzy complexity. Consequently, the reader is given useful insights into the nature of fuzzy computations and practical impediments when measuring uncertain data. Given materials and methods, current paper provides a broad perspective by evaluating the reliability characteristics of a repairable Substation Automation System (SAS) that is one of the fundamental elements in Smart Grids (SGs). In this regard, quantitative results and diagrammatic outputs are supported by a detailed analysis under different assumptions. Our findings demonstrate that fuzzy outputs are computationally tractable and properly estimated. Besides, this investigation shows how the objective SAS can respond to the variations in reliability data. The framework proposed here encourages the continuation of the work towards more applications in electric power components and systems. As far as we know, there are no studies on these techniques, results and remarks. [ABSTRACT FROM AUTHOR]

This paper sheds new lights on data uncertainty in fuzzy reliability computations to achieve the best possible accuracy using minimum data. To the best of our knowledge, there are major drawbacks to implement Conventional Fuzzy Arithmetic (CFA): catastrophic overestimation, non-applicability to real-world systems and complex computations based on impractical optimizations. A novel approach namely Fuzzy Transformation Method (FTM) has recently been put forward that eliminates the core problems of CFA. The present paper aims to validate the applicability of FTM to the reliability issues. Few researchers have addressed the issues of both symmetric and asymmetric uncertainty distributions in Fuzzy Failure Rates and how a fuzzy result can profoundly come under the influence of them. Hence, a comprehensive investigation is launched to evaluate the uncertainties and some beneficial observations are provided as well as sensitivity analysis and component importance measure in fuzzy frameworks. An interesting correlation between the component importance and input-output uncertainties is observed. Additionally, pictorial representations, results and remarks are numerically discussed. We opted for All-Digital Protection Systems (ADPSs) due to novelty of them and their impacts on substation reliability. Until now, there has not been provided a fuzzy perspective concerning reliability of ADPSs. [ABSTRACT FROM AUTHOR]

Highlights: [•] We propose a set of composite reliability evaluation models. [•] We assess the role of automated substations on the distribution system reliability. [•] SAS plays a vital role in the enhancement of the distribution system reliability. [•] System reliability is significantly improved by implementing the DA schemes. [•] We rank various automated distribution systems based on their reliability. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims to present a comprehensive technique to quantitatively assess the reliability of substation automation systems. The technique is based on the tie-sets methodology. In order to demonstrate the application of the proposed technique, a variety of substation automation architectures is first introduced. The associated reliability block diagrams as well as the exact system reliability are then given. The impacts and the degree of importance of various components on the reliability of substation automation systems are presented. Two suitable measures of importance are selected. The first is the Birnbaum’s measure used to determine the bottleneck of the system reliability. The second measure uses criticality importance to diagnose failures and generating repair or inspection checklists. [Copyright &y& Elsevier]

Highlights: [•] Different components of TCR–FC type SVC are introduced. [•] Using Markov process, a reliability Markov model for TCR–FC type SVC is obtained. [•] An equivalent three-state model for TCR–FC type SVC is proposed. [•] A sensitivity analysis for the availability of the equivalent model is carried out. [Copyright &y& Elsevier]