High-Voltage Equipment of Power Systems : Design, Principles of Operation, Testing, Monitoring and Diagnostics

This textbook covers in detail the problem of improving the reliability and service life of high-voltage equipment in electric power systems, mainly through testing, monitoring, and diagnostics, which support the timely repair or replacement of equipment. The main focus is on high-voltage power and instrument transformers, switching devices, powerful rotating electric machines, capacitors, bushings, and power cables. The design, purpose, and principle of operation for each respective type of equipment, as well as adverse factors that can lead to defects (primarily in insulation) – and, as a result, to accelerated aging (wear) and failure – are considered. In turn, the scientific and technological foundations and practical application of testing, monitoring, and diagnostics to determine the technical condition of equipment are described. Considerable attention is paid to new and promising methods for testing under voltage (without interrupting operation) – such as pulsed flaw detection and dielectric spectroscopy. In addition, the authors propose a number of helpful physical concepts and technical solutions. The book stands out in terms of the breadth and depth of the consideration of the problem, which reflects recent trends and concepts for the development of the electric power industry, and its convincing demonstration of the capabilities of traditional and advanced methods in relation to the main equipment used in electric power systems. The textbook is intended for undergraduate and graduate students in the field of high-voltage technologies for electric power systems. It also benefits engineering personnel working with electric power systems and in the electrical industry. Preface Contents 1 Past, Present and Future of Electric Power Systems (Brief Excursion) 1.1 Brief History of the Creation and Development of Power Systems 1.2 Main Tendencies in the Development of Electric Power Systems References 2 Characteristics of the Main Elements of Electric Power Systems 2.1 Power and Instrument Transformers 2.1.1 Purpose of Power Transformers 2.1.2 Transformers with Different Insulation 2.1.3 Purpose and Features of Instrument Transformers (ITs) 2.1.4 The Faults, Which Occurs Inside a Power Transformer 2.1.5 Disconnectors 2.1.6 Circuit Switchers and Switchgear Assemblies 2.1.7 Switchgear Assemblies 2.1.8 Design of an Air-Insulated Switchgear Substation Based on New Technology 2.1.9 Layout Reconfiguration and Optimization 2.2 Circuit Breakers and Other Switching Devices 2.2.1 Circuit Breakers 2.3 Rotating Machines 2.3.1 Main Insulation 2.3.2 Turn-to-Turn Insulation 2.4 Power Capacitors 2.5 Bushings 2.5.1 Low Voltage Bushings 2.5.2 High Voltage Bushings 2.6 Cables 2.6.1 Short History and Future of Electrical Cables 2.6.2 Insulation and Design of Power Cables References 3 Insulating Materials and Media Used in High-Voltage Elements of Electric Power Systems 3.1 The Most Important Characteristics of Insulating Materials and Media 3.1.1 Resistivity of Dielectric Materials 3.1.2 Variation of Dielectric Properties with Temperature 3.1.3 Potential Distribution in Dielectrics 3.1.4 Dielectric Strength 3.1.5 Influences Water Penetration and Ionizing Radiation 3.1.6 Arc Tracking of Insulation 3.1.7 Thermal Aging 3.2 Solid Dielectrics 3.2.1 Organic Insulating Materials 3.2.2 Inorganic Insulating Materials 3.3 Liquid Dielectrics 3.3.1 General Consideration 3.3.2 Mineral Insulating Oils 3.3.3 Synthetic Liquid Insulation 3.4 Insulating Gases and Vacuum 3.4.1 General Properties of Gases 3.4.2 Breakdown of Gases 3.4.3 Relative Dielectric Strengths of Gases 3.4.4 Corona and Breakdown in Inhomogeneous Fields 3.4.5 Corona Discharges on Insulator Surfaces 3.4.6 Flashover on Solid Surfaces in Gases 3.4.7 Vacuum References 4 Effects on Equipment Causing Insulation Aging and Failure 4.1 Effects of Electrical Voltage 4.2 Mechanical Effects 4.3 Thermal Effects 4.4 Atmospheric Influences 4.5 Time Factor 4.6 Exposure to Aggressive Media 4.7 Force Majeure Factors Causing Equipment Failure References 5 Defects in High Voltage Equipment: Types and Content of Tests 5.1 Classification of Defects 5.2 Test Types 5.2.1 Type (Normalized) Tests 5.2.2 Proof (Control) Tests 5.2.3 Acceptance Tests 5.2.4 Periodic (Operational) Tests 5.2.5 Special Tests 5.3 Norms and Test Methods 5.4 Diagnostics and Monitoring 5.4.1 Diagnostics 5.4.2 Monitoring 5.5 Expert Systems References 6 Non-electrical Diagnostic Methods 6.1 Chemical Control Methods 6.1.1 Chromatographic Analysis of Dissolved Gases 6.1.2 Chemical and Physical Indicators for Estimation the Condition of Paper Insulation for Oil—Filled Apparatus in Operation 6.2 Vibration Control 6.3 Thermal Methods and Devices for Control and Diagnostics 6.4 Magnetic Structuroscopy 6.5 Acoustic Control Methods 6.6 Acoustic Emission Diagnostics 6.7 Radiation Diagnostics References 7 Traditional Electrical Diagnostic Methods 7.1 Insulation Condition Monitoring by PD Registration 7.2 Measurement of Idling Losses 7.3 Measurement of the Transformation Ratio 7.4 Insulation Resistance Monitoring for Transformer Windings 7.5 Measurement of Winding DC-Resistance 7.6 Short-Circuit Resistance Monitoring 7.7 High Voltage Test References 8 Diagnostics of High-Voltage Equipment by Defectography Methods 8.1 Diagnostics of the Transformer Windings Condition by Probing Pulses 8.1.1 Physical Basis and Development of Pulsed Diagnostics 8.1.2 Development of Pulsed Diagnostics Technology 8.1.3 Frequency Analysis as a Development of Pulsed Diagnostics 8.1.4 Probing Transformer Windings with Nanosecond Pulses 8.1.5 Technology of Single-Stage Pulsed Defectography 8.1.6 ON-LINE Monitoring of Winding Condition 8.2 Defectography Method for Rotating Machines Diagnostics References 9 Dielectric Spectroscopy Technology 9.1 Basic Fundamental of Dielectric Spectroscopy 9.2 Polarization and Depolarization Current Measurement 9.3 Recovery Voltage Measurement 9.4 Frequency Time Domain Spectroscopy References 10 Diagnostics of High Voltage Equipment 10.1 Transformers and Other Oil-Filled Equipment 10.2 Circuit Breakers and Other Switching Devices 10.3 High Voltage Turbogenerators and Other Rotating Machines 10.4 Capacitors and Capacitor Banks 10.5 High Voltage Bushings 10.6 Gas-Insulated Switch Gears (GIS) References 11 Diagnostics of High-Voltage Cable Lines 11.1 Acceptance Testing of Power Cables 11.1.1 Checking the Integrity and Phasing of the Cable Cores 11.1.2 Measurement of Insulation Resistance 11.1.3 Rectified Current High Voltage Test 11.1.4 Power Frequency Overvoltage Test 11.1.5 Determination of Active Resistance of Cable Cores 11.1.6 Determination of the Electrical Performance of Cores 11.2 Diagnostics of Power Cables 11.3 Monitoring Cable Lines References 12 Diagnostics of Insulating Structures of Overhead Power Lines and Outdoor Substations 12.1 Brief Information About Insulators for Overhead Transmission Lines and Outdoor Substations and the Features of their Working Conditions 12.2 Simulating Lightning and Switching Surges for Testing 12.3 Voltage–Time Characteristic 12.4 Insulation Coordination 12.4.1 Statistical Approach to Insulation Coordination 12.4.2 Correlation Between Insulation and Protection Levels 12.5 Control of Thermal and Mechanical Resistance References Conclusion Appendix A Appendix B