Contents Cover Title Page Copyright Page Preface Acknowledgments Abbreviations and Symbols Chapter 1 Introduction References Chapter 2 Superconductivity 2.1 The Basic Properties of Superconductors 2.2 Critical Parameters 2.3 Classification and Magnetization 2.4 Measurement Technologies of Critical Parameters References Chapter 3 Mechanical Properties and Anisotropy of Superconducting Materials 3.1 Mechanical Properties 3.2 Electromagnetic Anisotropy 3.3 Critical Current Characteristics of LTS Materials 3.4 Irreversible Fields of Superconducting Materials 3.5 Critical Temperature of Several Kinds of HTS Materials 3.6 Thermodynamic Properties of Practical Superconducting Materials References Chapter 4 Stability of Superconductors 4.1 Critical States 4.2 Adiabatic Stabilization 4.3 Adiabatic Stability with Flux Jump 4.4 Self-Field Stability 4.5 Dynamic Stability 4.6 Cryostability 4.7 NPZ Velocity in Adiabatic Composite Superconductors 4.8 Stability of HTS Bulks 4.9 Mechanical Stability of Superconducting Magnets 4.10 Degradation and Training Effect of Superconducting Magnets 4.11 Quench and Protection of Superconducting Magnets 4.12 Tests of Stability References Chapter 5 AC Losses 5.1 AC Losses of Slab 5.2 AC Losses of Concentric Cylinder 5.3 AC Losses of Hybrid Concentric Cylinder 5.4 AC Losses of Concentric Hollow Cylinder in Longitudinal Field 5.5 AC Losses for Large Transverse Rotating Field 5.6 AC Losses with Different Phases between AC Field and AC Current 5.7 AC Losses for other Waves of AC Excitation Fields 5.8 AC Losses for other Critical State Models 5.9 Other AC Losses 5.10 Measurements of AC Loss 5.11 AC Losses Introduction of Superconducting Electrical Apparatus References Chapter 6 Brief Introduction to Fabricating Technologies of Practical Superconducting Materials 6.1 NbTi Wire 6.2 Nb Sn Wire 3 6.3 Nb Al Wire 3 6.4 MgB Wire 2 6.5 BSCCO Tape/Wire 6.6 YBCO Tape 6.7 HTS Bulk References Chapter 7 Principles and Methods for Contact-Free Measurements of HTS Critical Current and n Values 7.1 Measurement Introduction of Critical Current and n Values 7.2 Critical Current Measurements of HTS Tape by Contact-Free Methods 7.3 n Value Measurements of HTS Tape by Contact-Free Methods 7.4 Analysis on Uniformity of Critical Current and n Values in Practical Long HTS Tape 7.5 Next Measurements of Critical Currents and n Values by Contact-Free Methods References Chapter 8 Cryogenic Insulating Materials and Performances 8.1 Insulating Properties of Cryogenic Gas 8.2 Insulating Characteristics of Cryogenic Liquid 8.3 Insulating Properties of Organic Insulating Films 8.4 Cryogenic Insulating Paints and Cryogenic Adhesive 8.5 Structural Materials for Cryogenic Insulation 8.6 Inorganic Insulating Materials References Chapter 9 Refrigeration and Cryostats 9.1 Cryogens 9.2 Cryostat 9.3 Refrigeration 9.4 Cooling Technologies of Superconducting Electric Apparatus References Chapter 10 Power Supplying Technology in Superconducting Electrical Apparatus 10.1 Current Leads 10.2 Superconducting Switch 10.3 Flux Pump References Chapter 11 Basic Structure and Principle of Superconducting Apparatus in Power System 11.1 Cable 11.2 Fault Current Limiter 11.3 Transformer 11.4 Rotating Machine-Generator/Motor 11.5 Superconducting Magnetic Energy Storage (SMES) 11.6 Superconducting Flywheel Energy Storage (SFES) 11.7 Other Industrial Applications References Chapter 12 Case Study of Superconductivity Applications in Power System-HTS Cable 12.1 Design of AC/CD HTS Cable Conductor 12.2 Electromagnetic Design of AC/CD Cable Conductor 12.3 Analysis on AC Losses of DC HTS Cable 12.4 Design of AC WD HTS Cable Conductor 12.5 Design of DC HTS Cable Conductor 12.6 Design of Cryostat 12.7 Manufacture of CD HTS Cable Conductor 12.8 Bending of HTS Cable 12.9 Termination and Joint 12.10 Circulating Cooling System and Monitoring System References Appendix A.1 Calculations of Volumetric Heat Capacity, Thermal Conductivity and Resistivity of Composite Conductor A.2 Eddy Current Loss of Practical HTS Coated Conductor (YBCO CC) A.3 Calculation of Geometrical Factor G A.4 Derivation of Self and Mutual Inductances of CD Cable A.5 Other Models for Hysteresis Loss Calculations of HTS Cable A.6 Cooling Arrangements References Index This edition first published 2013 © 2013 Science Press. 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If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Wang, Yinshun. Fundamental elements of applied superconductivity in electrical engineering / Yinshun Wang. pages cm Includes bibliographical references and index. ISBN 978-1-118-45114-4 (cloth)  1. Superconductors. 2. Electric power. 3. Superconductivity. 4. Electrical engineering. I. Title. TK454.4.S93W26 2013 621.3′5–dc23 2012049085 A catalogue record for this book is available from the British Library. ISBN: 9781118451144 Preface Since its discovery, superconductivity and its applications have become one of the most active frontiers in modern science and technology. With the progress in exploration and research of superconductivity over nearly half a century, the practical NbTi and Nb Sn superconducting wires 3 were successfully fabricated in the 1960s. Superconducting technology, especially superconducting magnet technology, was then put into applications. However, it is difficult for superconductors to be extensively used since they must work at a liquid helium temperature of 4.2 K. Although the alternating current (AC) losses of superconducting windings is much lower than those of conventional copper windings, the effect of 1 W power consumption generated at a liquid helium temperature is at least equivalent to 500 W consumption of cooling power at room temperature. Therefore, the AC loss is not fully compensated for by reduction in AC losses, and the operating cost of superconducting electrical equipment is expensive, except in direct current (DC) applications. Until the 1980s, the AC application of the Low Temperature Superconductors (LTS) in a power system had not made substantial progress. Since the High Temperature Superconductor (HTS) was discovered in 1986, the application of HTS electrical equipment operating at the liquid nitrogen temperature of 77 K came into being, and superconducting power technology was hoped to be applied in electrical power systems. Great progress was made in development of HTS materials in the late 1990s, and practical HTS tapes were commercially realized. Research on superconducting power technology has made important and significant progress in many countries. At present, many superconducting equipment prototypes, such as superconducting cable, superconducting transformer, superconducting Fault Current Limiter (FCL), superconducting motor/generator, superconducting magnetic energy storage and other superconducting equipment, have been developed and demonstrated. At present, several groups of HTS cable prototypes operate in live grids. Superconducting technology has also found important applications in information technology, traffic transportation, scientific instrument, medical technology, national defence, large scientific projects and other fields besides the energy field. Superconducting power technology is highly comprehensive and interdisciplinary, and related to superconducting technology, electric power technology, cryogenic insulation, cryogenic refrigeration, materials science and technology, etc. At the present, it is a promising research field of new science and high technology, with important scientific significance and application prospects in power systems. At the same time, superconducting power technology will be one of the key technologies in the future Smart Grid. It is predicted that this technology will become a practical technology of extensive scale and play an important role in energy saving, emission reduction, low carbon economy, renewable energy resources, and in other fields. This book briefly introduces the basic theory of superconductivity. According to the knowledge structure and the order required in application of superconducting technology, electromagnetic properties of practical superconducting materials, stability, AC losses, processing technology, measurement of critical current and n values by contact-free methods, cryogenic insulation, cryostat and refrigeration, current leads and flux pump, are presented respectively. The principles and structures of various superconducting equipment are also described. Finally, high-T superconducting c (HTS) cables, and superconductivity applications in power systems, are systematically described to show how the basic technologies described elsewhere in the book fit together. The content of the book focuses on the fundamental elements of applied superconductivity in electrical engineering. A feature of this book is that experimental technology is added to related chapters together with the introduction of fundamental theoretical and technological principles. There are 12 chapters in the book. The first chapter briefly introduces applications of superconducting power technology with several superconducting apparatus used in power systems. Chapter 2 presents the basic theories and critical parameters of superconductors. Chapter 3 describes mechanical and electromagnetic properties of superconducting materials. Chapter 4 introduces the stability and quench characteristics of superconducting materials and magnets, and protection technology of superconducting magnets. Chapter 5 systematically describes various AC losses of superconducting in commercial frequency power, which includes hysteresis loss, magnetic flux flow loss, coupling and eddy current losses, and methods of measuring AC loss. Chapter 6 briefly lists the preparation techniques of practical superconducting materials. Chapter 7 presents theory and measurements of critical current and n values in practical HTS tapes by contact-free methods, and their evaluation and calculation of non-uniformity are also included. Chapter 8 concerns the insulation characteristics of some cryogenic gas, cryogenic liquid, organic insulation film materials, inorganic insulating materials and cryogenic adhesive. Chapter 9 mainly shows the heat-conduction theory, cryogenic device design and cryogenic refrigeration technology. Chapter 10 systematically introduces the design principles and methods of various current leads, including conductor-cooled current leads, gas-cooled lead, Peltier current lead (PCL) and the hybrid current lead, the applications of superconducting persistent current switch (PCS) and superconducting flux pump technology. Chapter 11 presents basic structures of several superconducting apparatus in power systems. As in the case of the application of superconductivity in a power system, Chapter 12 systematically describes the design of HTS cable.