Preface

**Chapter 8 143**

**Chapter 9 169**

Reliability Evaluation of Power Systems

*by Abdullah M. Al-Shaalan*

Microgrid System Reliability

*by Razzaqul Ahshan*

**II**

In today's highly automated and digitalized world, the terms *reliability, maintenance*, and *availability* (RMA) are considered as forming the core part of the contemporary reliability engineering discipline. Indeed, system engineers and logisticians may be regarded as being the primary users of the methods and techniques in RMA. However, because of continuous automation and acknowledging the fact that computers and microchips find their way into countless modern-day applications, products, and systems, which in turn require increased levels of RMA, the latter impact their associated lifecycle costs and their usefulness. Hence, reliability techniques are equally applied to hardware and software.

Thus, the term *reliability*, although having a number of definitions, is generally accepted to refer to the degree to which a system, product, or component performs its intended functions under stated conditions for a specified period of time without failure. In addition to the above definition, the terms *maintainability* and *availability* are also used to describe in the former case the probability of a system, product, or component to be repaired in a defined environment within a specified time period and that the repaired system, product, or component in the latter instance is readily operational/functional. The American Society for Quality, as well as the International Standards Organization, among other renowned bodies provide detailed and area-specific definitions.

Amid a plethora of challenges, the most important one being ongoing climate change, systems engineering areas will be called upon to deliver products and offer services to boost a higher degree of reliability, maintainability, and availability, placing an emphasis on designing for reliability and postproduction management systems.

This book comprises nine chapters split in two sections.

The first section discusses maintenance models and policies.

The first chapter introduces a contemporary maintenance strategy in line with the ISO 55000 series of asset management standards. The latter may be regarded as the successor to Publicly Available Specification PAS55 of the British Standards Institution. The suggested strategy was validated in electric power generation systems and transport vehicles.

The advantages of condition-based maintenance over scheduled maintenance regarding the safety and lifetime cost of an aircraft fuselage are discussed in the second chapter.

Meta-action units as the basic analysis and control unit concerning computer numerical-controlled machines are presented in the next chapter, which also portrays an overview of the respective reliability technology.

A number of surrogate modeling methods have been introduced to reduce modelspecific evaluation time and are applied in cases in which the outcome of interest

may not be measured in a straightforward and unequivocal manner. The following research work discusses a method based on radial basis functions aimed at probabilistic analysis applications.

The last chapter of the first section focuses on the basic mechanisms pertaining to specific reliability issues, such as thermal drift and long-term storage drift observed in microelectromechanical systems, by providing the corresponding reliability analysis of the performed experiments.

The second section presents four chapters on reliability issues in industrial networks.

The opening chapter focuses on the resolution of a mixed model regarding the design of large-size networks, by introducing an algorithm concerning connectivity and reliability by combining network survivability and network reliability approaches.

The treatment of uncertainties in probabilistic risk assessment is the subject area of the next chapter, which investigates uncertainty handling approaches pertaining to the analysis of fault tress and event trees as a means to overcome observed ambiguities.

A number of fundamental concepts concerning the reliability evaluation of power systems are discussed in this chapter by deriving a number of measures, criteria, and performance-related indices.

In a similar case, the last chapter discusses the reliability evaluation of a microgrid system acknowledging the intermittency effect of renewable energy sources, such as wind, by utilizing the Monte Carlo simulation technique.

It is hoped that the outcomes presented herein may serve as a platform for further research.

> **Dr. Leo D. Kounis** Hellenic Ministry of Defense, Communication and Informatics Battalion, Greece

Section 1

Maintenance Models

and Policies

Section 1
