Gas Insulated Transmission Lines (GIL)

Gas-insulated transmission lines (GIL) is an established high
voltage technology used when environmental or structural
considerations restrict the use of overhead transmission lines.
With an overview on the technical, economical and environmental
impact and power system implications of GIL, this guide provides a
complete understanding of its physical design, features and
advantages. The author illustrates how to evaluate when GIL would
be the best solution during the planning sequence and how to apply
GIL in the electricity power network.

Other key features include:

• operation and maintenance requirements with information on
  repair processes, duration, and different monitoring systems
  enabling the achievement of reliable and safe operation;

• a wide variety of realized applications from across the world
  over the past 35 years, illustrating typical fields of application
  through descriptions of real projects that the author has worked
  on; and

• future application possibilities in a smart transmission
  network, used for solving power transmission problems.

This is an essential reference for engineers involved in
planning and executing bulk power transmission projects overground,
in tunnels or buried. It offers a concise summary of all areas of
the subject and is the perfect aid for utility power engineers,
consulting engineers and manufacturers worldwide.

Auteur
**Hermann J. Koch, Principle Expert, Power Transmission, Siemens, Germany
Mr Koch currently works in the field of high voltage switchgear and high voltage transmission lines with Siemens in Germany. He became Principal Expert after over-seeing the installation of the first second generation GIL (gas insulated transmission lines) in Geneva, Switzerland in 2001. Since then he has worked on many projects with Siemens. Mr Koch created a successful tutorial Gas Insulated Substations with the IEEE PES Substations Committee, which has been presented in more than twenty countries including the USA, Canada, South America and India.

Résumé
Gas-insulated transmission lines (GIL) is an established high voltage technology used when environmental or structural considerations restrict the use of overhead transmission lines. With an overview on the technical, economical and environmental impact and power system implications of GIL, this guide provides a complete understanding of its physical design, features and advantages. The author illustrates how to evaluate when GIL would be the best solution during the planning sequence and how to apply GIL in the electricity power network. Other key features include:

• operation and maintenance requirements with information on repair processes, duration, and different monitoring systems enabling the achievement of reliable and safe operation;
• a wide variety of realized applications from across the world over the past 35 years, illustrating typical fields of application through descriptions of real projects that the author has worked on; and
• future application possibilities in a smart transmission network, used for solving power transmission problems.
  This is an essential reference for engineers involved in planning and executing bulk power transmission projects overground, in tunnels or buried. It offers a concise summary of all areas of the subject and is the perfect aid for utility power engineers, consulting engineers and manufacturers worldwide.

Contenu
Foreword xiii Acknowledgements xv

1 Introduction 1

1.1 Changing Electric Power Supply 1

1.2 Advantages of GIL 4

2 History 7

2.1 Transmission Network Development 7

2.2 Historical Development of GIL 20

3 Technology 39

3.1 Gas Insulation 41

3.1.1 Free Gas Space 42

3.1.2 Insulators 42

3.1.3 Gas-Tight Enclosure 44

3.1.4 Insulating Gases 46

3.2 Basic Design 65

3.2.1 Overview 65

3.2.2 Dielectric Dimensioning 68

3.2.3 Thermal Dimensioning 68

3.2.4 Insulation Coordination 68

3.2.5 Electrical Optimization 69

3.2.6 Transmission Network Studies 69

3.2.7 Gas Pressure Dimensions 70

3.2.8 High-Voltage Design Tests 70

3.2.9 Current Rating Design 72

3.2.10 Short-Circuit Rating Design 73

3.2.11 Internal Arc Design 74

3.2.12 Electromagnetic Current Forces Design 76

3.2.13 Mechanical Design 76

3.2.14 Integrated Overvoltage Protection 77

3.2.15 Particles 78

3.2.16 Thermal Design 79

3.2.17 Seismic Design 86

3.3 Product Design 93

3.3.1 Technical Data 93

3.3.2 Conductor Pipe 95

3.3.3 Enclosure Pipe 95

3.3.4 Size of Gas Compartment 97

3.3.5 Insulators 98

3.3.6 Sliding Contacts 100

3.3.7 Modular Design 100

3.3.8 Overhead Line Connection 103

3.3.9 Bending Radius 103

3.3.10 Joint Technology for Conductor and Enclosure 104

3.3.10.1 Flanged Joints 105

3.3.11 Corrosion Protection 112

3.3.12 On-Site Assembly Work 116

3.3.13 Monitoring 117

3.4 Quality Control and Diagnostic Tools 123

3.4.1 Quality of Parts 124

3.4.2 Quality of Processes 124

3.4.3 Partial Discharge Detection 125

3.4.4 High-Voltage Testing On-Site 126

3.4.5 Conclusion of Quality Control 130

3.5 Planning Issues 131

3.5.1 Network Impact 131

3.5.2 Reliability 139

3.5.3 Grounding/Earthing 141

3.5.4 Safety 141

3.5.5 Environmental Limitations 143

3.5.6 Electric Phase Angle Compensation 145

3.5.7 Loadability and Capability Overload 145

3.6 Specification Checklist 149

3.7 Laying Options 153

3.7.1 General 153

3.7.2 Above-Ground Installation 154

3.7.3 Trench-Laid 159

3.7.4 Tunnel-Laid 160

3.7.5 Directly Buried 166

3.7.6 Directional Boring 182

3.8 Long-Duration Testing 183

3.8.1 General 183

3.8.2 Tunnel Version 184

3.8.3 Directly Buried Version 197

3.8.4 Long-Duration Test Results 215

3.9 Gas Handling 217

3.9.1 General 217

3.9.2 Gas Mixture Handling 217

3.9.3 Conclusion 219

3.10 Commissioning and On-Site Testing 221

4 System and Network 225

4.1 General 225

4.2 Line Constants of GIL 225

4.3 Transmission Losses 228

4.4 Operational Aspects 231

4.5 Ageing 234

4.6 Internal Arc Fault 235

4.7 Maintenance 236

4.8 Repair 237

4.9 Personnel Safety 237

4.10 Insulation Coordination 238

4.11 System Control 247

5 Environmental Impact 253

5.1 General 253

5.2 Visual Impact 253

5.3 Electromagnetic Fields 254

5.4 Gas Handling 267

5.5 Thermal Aspects 267

5.6 Recycling 268

5.7 Lifecycle Assessment 269

5.8 CO2 Footprint 269 ...