Atmospheric Icing of Power Networks Book

1 Modern Meteorology and Atmospheric Icing Svein M. Fikke Jon Egill Kristjansson Bjorn Egil Kringlebotn Nygaard 1

1.1 Introduction 1

1.2 Atmospheric Icing - A Brief Survey of Icing Processes and their Meteorological Aspects 4

1.3 Icing Models 7

1.4 Introduction to Numerical Weather Prediction Models 9

1.5 Some Preliminary Applications of Fine-Scale Models 11

1.6 Condensation Schemes in NWP Models - Relevance for Icing Prediction 17

1.7 A Case Study: Using Numerical Weather Prediction Models to Forecast In-cloud Atmospheric Icing Episodes 21

1.8 Concluding Comments 26

References 27

2 Statistical Analysis of Icing Event Data for Transmission Line Design Purposes Masoud Farzaneh Konstantin Savadjiev 31

2.1 Introduction 31

2.2 Measurements and Database 32

2.3 Statistical Analysis and Modelling Ice Loads on Overhead Transmission Lines 40

2.4 Conclusions 78

References 80

3 Numerical Modelling of Icing on Power Network Equipment Lasse Makkonen Edward P. Lozowski 83

3.1 Introduction 83

3.2 The Fundamental Equation of Icing 85

3.3 Computing the Rate of Icing 89

3.4 Numerical Modelling 100

3.5 Conclusions 106

References 110

4 Wet Snow Accretion on Overhead Lines Pierre Admirat 119

4.1 Introduction 119

4.2 Microphysics of Wet Snow 119

4.3 Thermodynamic Analysis of Heat Exchanges 121

4.4 Modelling the Cylindrical Growth of Wet Snow Sleeves 129

4.5 Simulation of Accretion Mechanisms in Wind Tunnel Conditions 131

4.6 Observation of Accretion Mechanisms in Natural Climatic Conditions 140

4.7 Applications to Forecasting, Preventing, and Mapping the Wet Snow Overload Hazard 154

References 166

5 Effect of Ice and Snow on the Dynamics ofTransmission Line Conductors Pierre Van Dyke Dave Havard Andre Laneville 171

5.1 Introduction 171

5.2 Aeolian Vibrations 172

5.3 Wake-induced Oscillations 179

5.4 Galloping Conductors 182

5.5 Protection Methods for Galloping 209

5.6 Galloping Amplitudes 214

5.7 Ice Shedding 219

5.8 Bundle Rolling 222

5.9 Conclusion 224

References 225

6 Anti-icing and De-icing Techniques for Overhead Lines Masoud Farzaneh Christophe Volat Andre Leblond 229

6.1 Introduction 229

6.2 Anti-icing Techniques 230

6.3 De-icing Techniques 236

6.4 Joule-Effect Methods 245

6.5 Methods for Limiting Ice Accretion Weight 252

6.6 Practical Aspects 255

6.7 New Developments in Anti-icing Methods 258

6.8 Conclusions 264

References 265

7 Effects of Ice and Snow on the Electrical Performance of Power Network Insulators Masoud Farzaneh William A. Chisholm 269

7.1 Introduction 269

7.2 Insulator Functions, Dimensions and Materials 270

7.3 Ice and Snow Accretion on Insulators 271

7.4 Ice Flashover Processes and Mechanisms 278

7.5 Cold-Fog Flashover Process and Mechanisms 283

7.6 Snow Flashover Process and Mechanisms 286

7.7 Mathematical Modelling of Flashovers on Insulators Covered with Ice or Snow 291

7.8 Recommended Test Methods 301

7.9 Insulation Coordination for Ice and Snow Conditions 306

7.10 Mitigation Options to Improve Network Reliability in Winter Flashover Conditions 314

7.11 Conclusions and Recommendations 322

References 323

8 Design of Transmission Lines for Atmospheric Icing Anand Goel 327

8.1 Introduction 327

8.2 Types of Atmospheric Icing Accretion 328

8.3 Ice Accretion on Overhead Line Conductors and Structures 329

8.4 Ice Load Measurements 333

8.5 Standards for Ice Loads 335

8.6 Transmission Line System 338

8.7 Design Methodology 343

8.8 Deterministic Design Approach 344

8.9 Reliability-based Design (RBD) Approach 346

8.10 Return Period 349

8.11 Variability of Component Resistance 349

8.12 Other Loads 351

8.13 Ice/Snow Accretion Mitigation Techniques 356

8.14 Lessons from the 1998 Ice Storm 356

8.15 Concluding Remarks 357

Appendix 358

References 369

Index 373