Alternative Liquid Dielectrics for High Voltage Transformer Insulation Systems: Performance Analysis and Applications (IEEE Press Series on Power and Energy Systems)

375 Pages·2021·25.118 MB·English

by  U. Mohan Rao (editor), Issouf Fofana (editor), Ramanujam Sarathi (editor)

Alternative Liquid Dielectrics for High Voltage Transformer Insulation Systems
IEEE Press
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IEEE Press Editorial Board
Ekram Hossain, Editor in Chief
Jón Atli Benediktsson Xiaoou Li Jeffrey Reed
Anjan Bose Lian Yong Diomidis Spinellis
David Alan Grier Andreas Molisch Sarah Spurgeon
Elya B. Joffe Saeid Nahavandi Ahmet Murat Tekalp
Alternative Liquid Dielectrics for High Voltage
Transformer Insulation Systems
Performance Analysis and Applications
Edited by
U. Mohan Rao
Université du Québec à Chicoutimi, Canada
I. Fofana
Université du Québec à Chicoutimi, Canada
R. Sarathi
Indian Institute of Technology Madras, Chennai, India
Copyright © 2022 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.
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Library of Congress Cataloging- in- Publication Data
Names: Rao, U. Mohan (Ungarala Mohan), editor. | Fofana, I. (Issouf),
editor. | Sarathi, R. (Ramanujam), editor.
Title: Alternative liquid dielectrics for high voltage transformer
insulation systems : performance analysis and applications / edited by
U. Mohan Rao, I. Fofana, R. Sarathi.
Description: Hoboken, New Jersey : Wiley-IEEE Press, [2022] | Series: IEEE
Press series on power and energy systems | Includes bibliographical
references and index.
Identifiers: LCCN 2021042127 (print) | LCCN 2021042128 (ebook) | ISBN
9781119800163 (cloth) | ISBN 9781119800170 (adobe pdf) | ISBN
9781119800187 (epub)
Subjects: LCSH: Electric insulators and insulation–Liquids. | Liquid
dielectrics.
Classification: LCC TK3441.L5 A58 2022 (print) | LCC TK3441.L5 (ebook) |
DDC 621.319/37–dc23/eng/20211007
LC record available at https://lccn.loc.gov/2021042127
LC ebook record available at https://lccn.loc.gov/2021042128
Cover Design: Wiley
Cover Images: (center) © Panther Media GmbH/Alamy Stock Photo, (top) © Sam Robinson/Getty Images
Set in 9.5/12.5pt STIX Two Text by Straive, Pondicherry, India
10 9 8 7 6 5 4 3 2 1
This book is dedicated
to
Professor Issouf FOFANA
vii
Contents
Editor Biographies xv
List of Contributors xvii
Acknowledgments xxi
Editorial xxiii
1 Liquid Insulation for Power Transformers 1
U. Mohan Rao, I. Fofana, and E. Rodriguez Celis
1.1 Background of Liquid- Filled Transformers 1
1.2 Insulation System in Liquid-F illed Transformers 3
1.3 Insulation Aging Phenomena in Transformers 4
1.4 Transformer Insulating Liquids 6
1.4.1 Conventional Liquid Dielectrics 6
1.4.1.1 Mineral Insulating Oils 6
1.4.1.2 Polychlorinated Biphenyl 6
1.4.1.3 High- Temperature Hydrocarbons 7
1.4.2 Alternative Liquid Dielectrics 7
1.4.2.1 Natural Ester Liquids 7
1.4.2.2 Vegetable Oils 7
1.4.2.3 Synthetic Ester Liquids 7
References 8
2 Processing and Evaluation of Natural Esters 11
Niharika Baruah, Rohith Sangineni, Mrutyunjay Maharana, and Sisir Kumar Nayak
2.1 Introduction 11
2.2 Significant Natural Ester Liquids 14
2.2.1 Soybean Oil 14
2.2.2 Pongamia Pinnata Oil 14
2.2.3 Jatropha Curcas Oil 15
2.2.4 Palm Oil 15
2.2.5 Rapeseed Oil (Canola Oil) 16
2.3 Processing and Pretreatment 16
2.3.1 Extraction of Oil 16
2.3.1.1 Mechanical Extraction 17
2.3.1.2 Chemical Extraction 17
viii Contents
2.3.2 Transesterification 17
2.4 Properties and Evaluation of Natural Esters 20
2.4.1 Electrical Properties 20
2.4.1.1 AC Breakdown Voltage (ACBDV) 20
2.4.1.2 Dielectric Dissipation Factor (DDF) 21
2.4.1.3 Dielectric Constant 23
2.4.2 Chemical Properties 23
2.4.2.1 Water Content 23
2.4.2.2 Sulphur Content 24
2.4.2.3 Total Acid Number (TAN) 24
2.4.2.4 Oxidation Stability 24
2.4.3 Physical Properties 25
2.4.3.1 Pour Point 25
2.4.3.2 Flash and Fire Point 26
2.4.3.3 Interfacial Tension (IFT) 26
2.4.3.4 Thermal Conductivity 26
2.4.3.5 Viscosity 27
2.5 Degradation of Different Vegetable Oils 27
2.5.1 Fourier Transform Infrared Spectroscopy (FTIR) 29
2.5.2 Nuclear Magnetic Resonance (NMR) Study 30
2.6 Dissolved Gas Analysis in Natural Esters 31
2.6.1 Standard Gas Ratios 32
2.6.1.1 IEC Gas Ratios 32
2.6.1.2 Doernenburg Ratio Method 32
2.6.1.3 Rogers Ratio Method 34
2.6.1.4 Duval’s Triangle 34
2.7 Challenges in Using Natural Esters as Insulating Liquid 35
2.8 Conclusions and Future Scope 37
References 38
3 Compatibility of Esters with Cellulosic Insulation Materials 43
Cristina Méndez Gutiérrez, Carmela Oria Alonso, Cristina Fernández Diego,
Inmaculada Fernández Diego, Cristian Olmo Salas, Ahmet Kerem Köseoğlu,
Ramazan Altay, and Alfredo Ortiz Fernández
3.1 Introduction 43
3.1.1 Types of Solid Insulation 43
3.1.1.1 Classification According to Manufacturing Processes 43
3.1.1.2 Special Types of Paper Insulation 44
3.1.2 Mechanisms of Paper Degradation 45
3.1.2.1 Processes That Cause Degradation of the Cellulosic Insulation 45
3.1.2.2 Degradation Products from Cellulosic Insulation 46
3.1.3 Effect of Paper Deterioration on Transformer Performance 47
3.2 Procedure of Accelerated Thermal Aging 48
3.2.1 IEEE Std. C57.100 48
3.2.2 IEC 60216 49
3.2.3 Accelerated Thermal Aging Conditions 50
3.2.3.1 Temperature 50
Contents ix
3.2.3.2 Atmosphere 50
3.2.3.3 Moisture 50
3.2.3.4 Other Materials 51
3.2.3.5 Electrical Stress 52
3.3 Assessment of Liquid Degradation 52
3.3.1 Physicochemical Properties 52
3.3.2 Dielectric Properties 53
3.4 Assessment of Paper Degradation 55
3.4.1 Chemical Properties 55
3.4.1.1 Moisture Content 55
3.4.1.2 Degree of Polymerization 55
3.4.1.3 Fourier Transform Infrared Spectroscopy and X-r ay Spectroscopy 58
3.4.1.4 Furanic Compounds, Methanol Content, and Gases Production 58
3.4.2 Mechanical Properties 59
3.4.2.1 Tensile Strength 59
3.4.2.2 Relationship Between Degree of Polymerization (DP) and Mechanical Properties 62
3.4.2.3 Scanning Electron Microscope (SEM) 62
3.4.2.4 Refractive Index of Cellulose Fibers (RI) 63
3.4.3 Dielectric Properties 64
3.4.3.1 Breakdown Voltage 64
3.4.3.2 Partial Discharges 65
3.4.3.3 Dielectric Loss Factor 65
3.4.3.4 Dielectric Permittivity 65
3.4.3.5 Conductivity 66
3.4.3.6 Polarization and Depolarization Currents 66
3.5 Remaining Life of Transformer Insulation 66
3.5.1 IEEE C57.91 67
3.5.2 IEC 60076- 7 69
3.5.3 Kinetic Approach to Modeling 71
3.5.3.1 Polymerization Degree 71
3.5.3.2 Tensile Strength 73
3.6 Conclusions 76
References 78
4 Degradation Assessment of Ester Liquids 85
A.J. Amalanathan, R. Sarathi, N. Harid, and H. Griffiths
4.1 Introduction 85
4.1.1 Types of Ester Fluids 85
4.1.2 Properties of Ester Fluids 86
4.1.2.1 Breakdown Voltage 87
4.1.2.2 Moisture Content 89
4.1.2.3 Flash Point and Fire Point 90
4.1.2.4 Viscosity 90
4.1.2.5 Oxidation Stability 91
4.1.2.6 Dielectric Constant and Dissipation Factor 91
4.1.2.7 Biodegradability 92
4.1.3 Fluid Maintenance and Storage Issues 92
x Contents
4.2 Procedure of Accelerated Thermal Aging 93
4.2.1 ASTM D1934- 95 93
4.2.2 IEC 62332- 2 93
4.2.3 Temperature 94
4.2.4 Atmosphere 94
4.2.5 Moisture 94
4.3 Assessment of Liquid Degradation 95
4.3.1 Partial Discharge Inception Voltage 95
4.3.1.1 Measurement of PDIV Under AC and DC Voltage 96
4.3.1.2 Measurement of PDIV Under Harmonic Voltage 97
4.3.2 Flow Electrification 98
4.3.2.1 Flow Electrification Measurement Methods 98
4.3.3 Spectroscopic Studies 102
4.3.3.1 UV- Visible Spectroscopy 103
4.3.3.2 Fluorescence Spectroscopy 104
4.3.4 Dielectric Response Spectroscopy 107
4.3.5 Physico- Chemical Studies 108
4.3.5.1 Interfacial Tension 108
4.3.5.2 Turbidity 109
4.3.5.3 Viscosity 109
4.3.5.4 Organic Composition of Oil Using GC- MS 110
4.4 Assessment of Paper Degradation 110
4.4.1 Surface Discharge Analysis 111
4.4.2 Surface Potential Measurement 112
4.4.3 Impedance Spectroscopy 113
4.4.4 Py- GC/MS 116
4.4.5 Laser- Induced Breakdown Spectroscopy 117
4.5 Conclusions and Future Scope 120
References 120
5 End Life Behavior of Ester Liquids in High- Voltage Transformers 127
U. Mohan Rao, I. Fofana, L. Loiselle, and T. Jayasree
5.1 Introduction 127
5.2 Evolution of Colloidal and Soluble Decay Particles 128
5.2.1 Perspective of Decay Particles 128
5.2.2 Size and Influence of Decay Particles 129
5.3 Colloidal Particles – Centrifugal Treatment (ASTM D1698) 130
5.3.1 UV Spectroscopy 132
5.3.2 Turbidity 133
5.3.3 Particle Counter 135
5.4 Soluble Particles – Fuller’s Earth Filtration (ASTM D7150) 137
5.4.1 UV Spectroscopy 137
5.4.2 Turbidity 138
5.4.3 Particle Counter 139
5.5 Feasibility of Fuller’s Earth Filtration for Ester Liquids 140
5.5.1 On Ratio of Fuller’s Earth to Liquid 141
5.5.2 On Treatment Temperature 142