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Группа авторов. Alternative Liquid Dielectrics for High Voltage Transformer Insulation Systems
Table of Contents
List of Tables
List of Illustrations
Guide
Pages
Alternative Liquid Dielectrics for High Voltage Transformer Insulation Systems. Performance Analysis and Applications
Editor Biographies
List of Contributors
Acknowledgments
Editorial
1 Liquid Insulation for Power Transformers
1.1 Background of Liquid‐Filled Transformers
1.2 Insulation System in Liquid‐Filled Transformers
1.3 Insulation Aging Phenomena in Transformers
1.4 Transformer Insulating Liquids. 1.4.1 Conventional Liquid Dielectrics
1.4.1.1 Mineral Insulating Oils
1.4.1.2 Polychlorinated Biphenyl
1.4.1.3 High‐Temperature Hydrocarbons
1.4.2 Alternative Liquid Dielectrics
1.4.2.1 Natural Ester Liquids
1.4.2.2 Vegetable Oils
1.4.2.3 Synthetic Ester Liquids
References
2 Processing and Evaluation of Natural Esters
2.1 Introduction
2.2 Significant Natural Ester Liquids
2.2.1 Soybean Oil
2.2.2 Pongamia Pinnata Oil
2.2.3 Jatropha Curcas Oil
2.2.4 Palm Oil
2.2.5 Rapeseed Oil (Canola Oil)
2.3 Processing and Pretreatment
2.3.1 Extraction of Oil
2.3.1.1 Mechanical Extraction
2.3.1.2 Chemical Extraction
2.3.2 Transesterification
2.4 Properties and Evaluation of Natural Esters
2.4.1 Electrical Properties. 2.4.1.1 AC Breakdown Voltage (ACBDV)
2.4.1.2 Dielectric Dissipation Factor (DDF)
2.4.1.2.1 Parallel Representation
2.4.1.2.2 Series Representation
2.4.1.3 Dielectric Constant
2.4.2 Chemical Properties. 2.4.2.1 Water Content
2.4.2.2 Sulphur Content
2.4.2.3 Total Acid Number (TAN)
2.4.2.4 Oxidation Stability
2.4.3 Physical Properties. 2.4.3.1 Pour Point
2.4.3.2 Flash and Fire Point
2.4.3.3 Interfacial Tension (IFT)
2.4.3.4 Thermal Conductivity
2.4.3.5 Viscosity
2.5 Degradation of Different Vegetable Oils
2.5.1 Fourier Transform Infrared Spectroscopy (FTIR)
2.5.2 Nuclear Magnetic Resonance (NMR) Study
2.6 Dissolved Gas Analysis in Natural Esters
2.6.1 Standard Gas Ratios
2.6.1.1 IEC Gas Ratios
2.6.1.2 Doernenburg Ratio Method
2.6.1.3 Rogers Ratio Method
2.6.1.4 Duval’s Triangle
2.7 Challenges in Using Natural Esters as Insulating Liquid
2.8 Conclusions and Future Scope
References
3 Compatibility of Esters with Cellulosic Insulation Materials
3.1 Introduction. 3.1.1 Types of Solid Insulation
3.1.1.1 Classification According to Manufacturing Processes
3.1.1.2 Special Types of Paper Insulation
3.1.2 Mechanisms of Paper Degradation
3.1.2.1 Processes That Cause Degradation of the Cellulosic Insulation
3.1.2.2 Degradation Products from Cellulosic Insulation
3.1.3 Effect of Paper Deterioration on Transformer Performance
3.2 Procedure of Accelerated Thermal Aging
3.2.1 IEEE Std. C57.100
3.2.2 IEC 60216
3.2.3 Accelerated Thermal Aging Conditions. 3.2.3.1 Temperature
3.2.3.2 Atmosphere
3.2.3.3 Moisture
3.2.3.4 Other Materials
3.2.3.5 Electrical Stress
3.3 Assessment of Liquid Degradation
3.3.1 Physicochemical Properties
3.3.2 Dielectric Properties
3.4 Assessment of Paper Degradation
3.4.1 Chemical Properties
3.4.1.1 Moisture Content
3.4.1.2 Degree of Polymerization
3.4.1.3 Fourier Transform Infrared Spectroscopy and X‐ray Spectroscopy
3.4.1.4 Furanic Compounds, Methanol Content, and Gases Production
3.4.2 Mechanical Properties
3.4.2.1 Tensile Strength. 3.4.2.1.1 Measurement of the Tensile Mechanical Properties of Paper Insulation
3.4.2.1.2 Limitations of the Tensile Strength as a Single Measure to Describe Mechanical Failure
3.4.2.1.3 Need for an Indirect Estimation of the Mechanical Properties of the Solid Insulation
3.4.2.2 Relationship Between Degree of Polymerization (DP) and Mechanical Properties
3.4.2.3 Scanning Electron Microscope (SEM)
3.4.2.4 Refractive Index of Cellulose Fibers (RI)
3.4.3 Dielectric Properties
3.4.3.1 Breakdown Voltage
3.4.3.2 Partial Discharges
3.4.3.3 Dielectric Loss Factor
3.4.3.4 Dielectric Permittivity
3.4.3.5 Conductivity
3.4.3.6 Polarization and Depolarization Currents
3.5 Remaining Life of Transformer Insulation
3.5.1 IEEE C57.91
3.5.2 IEC 60076‐7
3.5.3 Kinetic Approach to Modeling
3.5.3.1 Polymerization Degree
3.5.3.2 Tensile Strength
3.6 Conclusions
References
4 Degradation Assessment of Ester Liquids
4.1 Introduction
4.1.1 Types of Ester Fluids
4.1.2 Properties of Ester Fluids
4.1.2.1 Breakdown Voltage
4.1.2.2 Moisture Content
4.1.2.3 Flash Point and Fire Point
4.1.2.4 Viscosity
4.1.2.5 Oxidation Stability
4.1.2.6 Dielectric Constant and Dissipation Factor
4.1.2.7 Biodegradability
4.1.3 Fluid Maintenance and Storage Issues
4.2 Procedure of Accelerated Thermal Aging
4.2.1 ASTM D1934‐95
4.2.2 IEC 62332‐2
4.2.3 Temperature
4.2.4 Atmosphere
4.2.5 Moisture
4.3 Assessment of Liquid Degradation
4.3.1 Partial Discharge Inception Voltage
4.3.1.1 Measurement of PDIV Under AC and DC Voltage
4.3.1.2 Measurement of PDIV Under Harmonic Voltage
4.3.2 Flow Electrification
4.3.2.1 Flow Electrification Measurement Methods
4.3.2.1.1 Effect of Spinning Velocity
4.3.2.1.2 Effect of Temperature
4.3.3 Spectroscopic Studies
4.3.3.1 UV‐Visible Spectroscopy
4.3.3.2 Fluorescence Spectroscopy
4.3.4 Dielectric Response Spectroscopy
4.3.5 Physico‐Chemical Studies
4.3.5.1 Interfacial Tension
4.3.5.2 Turbidity
4.3.5.3 Viscosity
4.3.5.4 Organic Composition of Oil Using GC‐MS
4.4 Assessment of Paper Degradation
4.4.1 Surface Discharge Analysis
4.4.2 Surface Potential Measurement
4.4.3 Impedance Spectroscopy
4.4.4 Py‐GC/MS
4.4.5 Laser‐Induced Breakdown Spectroscopy
4.5 Conclusions and Future Scope
References
5 End Life Behavior of Ester Liquids in High‐Voltage Transformers
5.1 Introduction
5.2 Evolution of Colloidal and Soluble Decay Particles. 5.2.1 Perspective of Decay Particles
5.2.2 Size And Influence of Decay Particles
5.3 Colloidal Particles – Centrifugal Treatment (ASTM D1698)
5.3.1 UV Spectroscopy
5.3.2 Turbidity
5.3.3 Particle Counter
5.4 Soluble Particles – Fuller's Earth Filtration (ASTM D7150)
5.4.1 UV Spectroscopy
5.4.2 Turbidity
5.4.3 Particle Counter
5.5 Feasibility of Fuller's Earth Filtration for Ester Liquids
5.5.1 On Ratio of Fuller's Earth to Liquid
5.5.2 On Treatment Temperature
5.6 Conclusions and Future Scope
References
6 Prebreakdown and Breakdown Phenomena in Ester Dielectric Liquids
6.1 Introduction
6.2 Research Methods in Assessment of Prebreakdown Phenomena in Ester Liquids
6.2.1 Standard‐Based Approach
6.2.2 Experimental Approach
6.3 Initiation of Streamers in Dielectric Liquids
6.3.1 Influence of Tip Radius on Streamer Initiation
6.3.2 Streamer Initiation Mechanisms
6.3.3 Research Progress on Streamer Initiation in Esters vs. Mineral Oil
6.4 Streamer Propagation
6.4.1 Overview of Propagation Modes
6.4.2 Streamer Development Theories
6.4.3 Streamer Propagation and Breakdown in Esters vs. Mineral Oils
6.4.4 Influence of Nanoparticles on Prebreakdown Phenomena in Ester Liquids
6.5 Influence of Temperature on Prebreakdown Phenomena in Natural Ester Liquids
6.6 Influence of Thermal Aging on Prebreakdown Phenomena in Synthetic Ester Liquids
6.7 Conclusions and Future Scope
References
7 Miscibility and Engineering Application of a Novel Mixed Fluid
7.1 Introduction
7.2 Need and Research Progress of Mixed Insulating Liquids
7.3 Preparation Method for the New Mixed Insulating Oil. 7.3.1 Selection of the Base Oil
7.3.2 Determination of the Proportion
7.3.3 Improvement of Oxidation Stability
7.3.4 Stability Overall Performance
7.3.5 Performance of Novel Three‐Element Mixed Insulating Oil
7.4 Thermal Aging Characteristics of the New Mixed Insulation Oil–Paper Insulation and Its Delaying Thermal Aging Mechanism
7.4.1 Introduction
7.4.2 DP Values of Cellulose Paper
7.4.3 Mechanism of Delaying Thermal Aging
7.5 Mechanism of Property Enhancement of the New Mixed Insulation Oil on Power Frequency Breakdown of Oil–Paper Insulation. 7.5.1 Introduction
7.5.2 Oils Breakdown Voltage with Different Moisture Contents
7.5.3 Oils Breakdown Voltage with Different Temperatures
7.5.4 Oil Breakdown Voltage Under Combined Effects of Moisture and Temperature
7.5.5 Comparison of AC Breakdown Characteristics of Composite Insulation with Different Temperatures and Moisture Contents
7.5.6 Comparison of AC Breakdown Characteristics of Composite Insulation with Oil Gap
7.6 Enhancing Effect and Mechanism of the New Mixed Insulation Oil on Flashover Voltage of Oil–Paper Insulation. 7.6.1 Introduction
7.6.2 Surface Flashover Voltage of Oil‐Cellulose Insulation Pressboard
7.6.3 Surface Flashover Difference Analysis
7.7 Application of the New Mixed Insulation Oil: Service Experiences. 7.7.1 Introduction
7.7.2 Using the New Three‐Element Mixed Insulation Oil in 10 kV Transformer
7.7.3 Overheating and Discharge Fault Identification for Novel Three‐Element Mixed Oil‐Paper Insulation System
7.7.4 Fault‐Type Identification Model Based on Hydrogen, Ethane, and Acetylene
7.8 Conclusions and Future Scope
References
8 Natural Ester Nanosfluids as Alternate Insulating Oils for Transformers
8.1 Introduction
8.1.1 Importance of Nanofluids
8.1.2 Improvement of Natural Esters
8.1.2.1 Additives for Chemical Structure Modification
8.1.2.2 Addition of Nanoparticles
8.1.3 Commonly Used Nanoparticles
8.2 Preparation of Natural Ester Nanofluids and Stability Analysis
8.2.1 Preparation of Natural Ester Nanofluids
8.2.1.1 Different Methods of Nanofluid Preparation
8.2.1.1.1 Single‐Step Preparation Methodology
8.2.1.1.2 Two‐Step Preparation Methodology
8.2.1.1.3 Other Methods of Nanofluid Preparation
8.2.2 Stability of Natural Ester Nanofluids. 8.2.2.1 Stability of Nanofluids
8.2.2.1.1 DLVO Theory
8.2.2.2 Methods of Stability Improvement of Natural Ester Nanofluids
8.2.2.2.1 Chemical Method
Addition of Surfactant
pH Control
8.2.2.2.2 Mechanical Method
8.2.2.3 Methods of Stability Analysis of Natural Ester Nanofluids
8.2.2.3.1 Sedimentation Method
8.2.2.3.2 Dynamic Light Scattering (DLS) Method
8.2.2.3.3 UV‐Vis Spectrum Method
8.2.2.3.4 Turbidity Measurement
8.3 Properties of Natural Esters and Natural Ester Nanofluids
8.3.1 Physical Properties
8.3.2 Electrical Properties
8.3.2.1 Permittivity of Nanofluids
8.3.2.2 Partial Discharge and Breakdown Voltage in Nanofluids
8.3.2.2.1 Electron Scavenging Theory
8.3.2.2.2 Potential Well Model
8.3.2.2.3 Shallow Trap Theory
8.3.2.2.4 Hydrophilicity Theory
8.3.3 Thermal Properties
8.3.4 Aging Study of Natural Ester Nanofluids
8.3.5 Feasibility of Natural Ester Nanofluids as an Alternate Insulating Oil for Transformers
8.4 Conclusion
8.4.1 Stability Enhancement of Natural Ester Nanofluids
8.4.2 Simulation Model for Nanofluids
8.4.3 Design of Transformers Using Natural Ester Nanofluids
8.4.4 Mixed Fluids and Multiparticle Nanofluids
References
9 Dielectric Properties of Silica‐Based Synthetic Ester Nanofluid
9.1 Introduction
9.1.1 Need for Nanofluids
9.1.2 Methods of Property Enhancement of Nanofluids
9.2 Nanofluid Preparation and Characterization. 9.2.1 Nanoparticle Characterization
9.2.2 Nanofluid Preparation
9.2.3 Nanofluid Stability
9.2.3.1 Particle Size Analysis
9.2.3.2 Zeta Potential Analysis
9.2.3.3 Viscosity Measurement
9.3 Frequency Domain Dielectric Response. 9.3.1 Experimental Setup
9.3.2 Dielectric Constant
9.3.3 Dissipation Factor
9.4 Time Domain Dielectric Response. 9.4.1 Experimental Setup
9.4.2 Ion Mobility
9.4.3 Conductivity and Other Dielectric Properties
9.5 Conduction at High Electric Field. 9.5.1 Experimental Setup
9.5.2 I–U Characteristics
9.6 Corona Inception Voltage. 9.6.1 Experimental Setup
9.6.2 CIV Results and Discussion
9.6.3 Incipient Discharge Activity. 9.6.3.1 Corona Discharge Activity Under Harmonic AC Voltages
9.6.3.2 UHF Signal Energy Analysis
9.7 Conclusions and Future Scope
References
10 Behavior of Ester Liquids Under Various Operating Fault Conditions
10.1 Introduction
10.2 Dissolved Gas Analysis and Transformer Faults
10.2.1 Duval's Triangle
10.2.2 Duval's Pentagon
10.2.3 Research Progress on Various Faulty Conditions
10.3 Simulation of Various Faults in Laboratory Environment. 10.3.1 Low‐Energy Discharges (Surface Discharges)
10.3.2 Thermal Faults (Hotspot)
10.3.3 High‐Energy Discharges (Arcing)
10.4 Influence of Different Faults on the State of Liquid and Gassing Tendency
10.4.1 Effect on Gassing Tendency
10.4.2 Effect on Degradation
10.5 Conclusions and Future Scope
References
11 In‐Service Performance of Natural Esters
11.1 Introduction
11.2 Reasons Why These Utilities Chose a Natural Ester
11.3 Transformers Under Study
11.4 Summary of Research Applied to Manage These Transformers
11.5 Fluid Temperature at Rated Load
11.6 Breakdown Voltage and Water Content
11.7 Investigations into Oxidation and Handling Fluid‐Impregnated Paper
11.8 Study on Installation and Early Operation of a Power Transformer Filled with Natural Ester
11.9 Fleet Measurements
11.9.1 Dielectric Dissipation Factor, Interfacial Tension, and Acid Number
11.9.2 Water Content of Oil
11.9.3 Breakdown Voltage of Oil
11.9.4 Dissolved Gas Analysis
11.9.5 Electrical Testing of Transformers
11.10 Summary
References
Index. a
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