Live-Line Operation and Maintenance of Power Distribution Networks

Foreword xi

Preface xiii

Introduction 1

1 Overview 3

1.1 Basic Concept of Non-Service Interruption Working 3

1.1.1 Basic Method of Live Line Working 4

1.1.2 Bypass Working and Mobile Power Working 6

1.2 Development of Working Techniques 8

1.2.1 Development History of Live Line Working 8

1.2.2 From Live Line Working to Live Line Working Robot 10

1.2.3 Live Line Working by Helicopter 12

1.2.4 Development From Live Line Working to Non-Service Interruption Working 15

1.3 Power Supply Reliability and Power Outage Losses 15

1.3.1 Reliability Indexes 16

1.3.2 Analysis of Indexes of Power Supply Reliability 17

1.3.3 Power Outage Losses 20

1.4 Analysis of Effect of Working Techniques 23

References 26

2 Distribution Grid and Its Working Techniques 27

2.1 Basic Concept of Distribution Grid 27

2.2 Basic Configuration of Distribution Grid 31

2.2.1 Distribution Network Configuration 31

2.2.2 Composition of Overhead Distribution Lines 34

2.2.3 Composition of Distribution Cable Line 50

2.2.4 Other Common Distribution Equipment 54

2.3 Technical Principles of Distribution Non-Service Interruption Working 63

2.3.1 Earth Potential Working 65

2.3.2 Middle Potential Working 67

2.3.3 Equipotential Working 69

2.4 Types of Distribution Line Poles and Live Line Working 70

2.4.1 Classification of Pole Types 70

2.4.2 Conductor Spacing in Tower and Spacing Between Conductors and Surroundings 72

2.4.3 Types of Poles Suitable for Live Line Working 75

References 77

3 Theoretical Basis of Working Techniques 79

3.1 Analysis of Influence of Electricity on Human Bodies 79

3.1.1 Influence Brought by Current on Human Bodies 79

3.1.2 Influence of Electric Field on Human Bodies 81

3.2 Overvoltage During Working 84

3.2.1 Switching Overvoltage 85

3.2.2 Temporary Overvoltage 86

3.3 Dielectric Properties 89

3.3.1 Conductance and Insulation Resistance of Dielectric 89

3.3.2 Breakdown Strength and Discharge Characteristic of Dielectric 94

3.4 Insulation Coordination and Safety Spacing 101

3.4.1 Insulation Coordination 101

3.4.2 Safety Spacing 107

References 110

4 Common Working Tools and Usages 111

4.1 Insulating Tools 111

4.1.1 Common Insulating Materials 111

4.1.2 Insulating Poles 114

4.1.3 Insulating Ropes and Cords 118

4.2 Protective Appliances 122

4.2.1 Insulating Shielding Appliances 123

4.2.2 Insulating Blanket (Mat) 125

4.2.3 Insulating Protective Appliances 126

4.3 Other Working Tools 131

4.3.1 Tensioner 131

4.3.2 Insulating Tape Lever Hoist 132

4.3.3 Instruments and Meters 133

4.4 The Making of Working Tools 139

4.4.1 Material Selection 139

4.4.2 Design and Processing 141

4.4.3 Simulation Drill and Practical Application 144

4.5 The Usage and Management of Working Tools 146

4.5.1 Storage and Maintenance of Live Line Working Tools 146

4.5.2 Warehouse of Live Line Working Tools and Management 147

4.5.3 Modern Identifications and Intelligent Management of Tools 160

References 161

5 Test Techniques for Working Tools 163

5.1 Test Items 163

5.1.1 Classification of Tests 163

5.1.2 Test Items 164

5.1.3 Technical Standards of Tests 166

5.2 Test of Common Insulating Tools 169

5.2.1 Test of Insulating Pole 169

5.2.2 Test of Insulating Tackle 177

5.2.3 Test of Insulating Hard Ladder 178

5.2.4 Test of Insulating Rope 180

5.2.5 Test of Insulating Hand Tool 184

5.2.6 Test of Insulating Shielding Cover 187

5.2.7 Test of Insulating Blanket (Mat) 191

5.2.8 Test of Insulating Clothing (Shawls) 193

5.2.9 Test of Insulating Gloves 195

5.2.10 Test of Insulating Shoes (Boots) 197

5.2.11 Test of Insulating Helmet 198

References 200

6 Application of Aerial Device with Insulating Boom and Insulating Platform 201

6.1 Aerial Device with Insulating Boom 201

6.1.1 Introduction to Aerial Device with Insulating Boom 201

6.1.2 Use and Operation of Aerial Device with Insulating Boom 205

6.1.3 Maintenance and Service of Aerial Device with Insulating Boom 213

6.1.4 Test of Aerial Device with Insulating Boom 215

6.2 Insulating Platform 226

6.2.1 Introduction to Insulating Platform 226

6.2.2 Use and Maintenance of Insulating Platform 228

6.2.3 Test of Insulating Platform 229

6.3 Operational Robot 236

6.3.1 Introduction to Operational Robots 236

6.3.2 Working Tools 248

6.3.3 Test of Insulation Performance 251

References 255

7 Medium-Voltage Distribution Live Line Working 257

7.1 Basic Working Procedures and Methods 257

7.1.1 Meteorological Conditions for Working 257

7.1.2 Basic Working Procedures 260

7.1.3 Working Instructions 264

7.1.4 Basic Working Methods 265

7.2 Working Techniques for Simple and Regular Works 269

7.2.1 Repairing Conductors 269

7.2.2 Live Line Connection (Removal) of No-Load By-Pass Jumpers 272

7.2.3 Replacing Tension Insulators 286

7.2.4 Replacing Cross Arms and Insulators in a Suspension Pole 290

7.2.5 Replacing Lightening Arresters 293

7.3 Working Techniques for Complex and Comprehensive Works 296

7.3.1 Live Line Installation of a Pole 296

7.3.2 Replacing a Suspension Pole 310

7.3.3 Changing a Suspension Pole to a Tension Pole 316

7.3.4 On-Load Replacement of Pole-Mounted Switches 322

7.3.5 On-Load Installation of Pole-Mounted Breakers 332

References 337

8 Low-Voltage Distribution Live Line Working 339

8.1 Key Working Techniques 339

8.1.1 Safety Measures for Working 339

8.1.2 Technical Measures for Working 342

8.2 Working Items and Methods 343

8.2.1 Live Line Connection of a Low-Voltage Service Conductor 343

8.2.2 Connection of Power Source for a Low-Voltage Distribution Box 345

8.2.3 Live Line Treatment of a Broken Service Conductor 347

8.2.4 Live Line Replacement of a Three-Phase Four-Wire Watt-Hour Meter 348

8.2.5 Live Line Isolation of a Failed Watt-Hour Meter 350

References 351

9 Bypass Working and Mobile Power Working 353

9.1 Basic Methods of Bypass Working 353

9.1.1 Bypass Cable Method 354

9.1.2 Bypass Overhead Line Method 359

9.1.3 Safety Measures for Bypass Working 363

9.2 Mobile Generation Working Techniques 364

9.2.1 Operating Principle and Wiring 365

9.2.2 Operations of Mobile Generator Vehicle 366

9.2.3 Method of Power Supply by Mobile Generator Vehicle 371

9.3 EPS Working Techniques 374

9.3.1 Operating Principle of EPS 374

9.3.2 Operations of EPS Vehicle 378

9.3.3 Operating Essentials of Power Supply by EPS Vehicle 379

9.3.4 Maintenance of EPS Vehicle 381

9.4 Mobile Prefabricated Transformer Working Techniques 384

9.4.1 Power Supply Principle of Mobile Prefabricated Transformer 384

9.4.2 Changing Pole-Mounted Transformer 386

9.5 Cable Non-Service Interruption Working Techniques 391

9.5.1 Overview of Power Supply Using Bypass Cable 391

9.5.2 Equipment Commonly Used for Working 393

9.5.3 Main Working Techniques 403

References 432

10 Working Management and Emergency Measures 433

10.1 Work Management 433

10.1.1 Organization and Management 433

10.1.2 Safety Management 435

10.1.3 Relevant Regulations and Technical Standards 437

10.1.4 Working Management Documents 438

10.1.5 Management of New Working Subjects 439

10.1.6 Management of New R&D Projects 441

10.2 Training and Management of Workers 441

10.2.1 Induction Training of New Workers 442

10.2.2 Daily Training of Workers 442

10.2.3 Assessment and Management of Workers 443

10.2.4 Training Base 443

10.3 Emergency Measures for Working 444

10.3.1 Emergency Measures for Abrupt Change of Weather 445

10.3.2 Emergency Measures for Failure of Major Working Tools 446

10.3.3 Emergency Measures for Personal Injuries 448

10.3.4 Training and Drill 453

References 453

Annex: Distribution Non-service Interruption Working Instructions (Template) 455

Appendix 1: General Guidelines for Safety of Live Line Working 467

Appendix 2: Technical Guidelines for Common Working Tools 477

Index 501