Variable Frequency Transformers for Large Scale Power Systems Interconnection

ABOUT THE AUTHOR 1

PREFACE TO ENGLISH VERSION 2

PREFACE 4

1 POWER GRID DEVELOPMENT AND INTERCONNECTION 7

1.1 OVERVIEW 7

1.2 ENERGY REFORM AND THIRD GENERATION OF POWER GRIDS 8

1.3 LARGE-SCALE POWER ALLOCATION AND LARGE POWER GRID INTERCONNECTION 21

1.4 MAIN CONTENT OF THE BOOK 42

1.5 SUMMARY 44

REFERENCES 45

2 PROPOSAL AND APPLICATION OF VARIABLE FREQUENCY TRANSFORMER 47

2.1 OVERVIEW 47

2.2 VARIABLE FREQUENCY TRANSFORMER SYSTEM CONSTITUTION 47

2.3 BASIC FUNCTIONS OF VARIABLE FREQUENCY TRANSFORMER 55

2.4 START-UP AND CONTROL OF VARIABLE FREQUENCY TRANSFORMER 56

2.5 MECHANISM OF VFT IMPROVING THE SYSTEM STABILITY 58

2.6 EXISTING VARIABLE FREQUENCY TRANSFORMER APPLICATION IN POWER SYSTEM 61

2.7 VFT APPLICATION WITHIN GLOBAL ENERGY INTERCONNECTION 62

2.8 STUDYING PROMINENT PROBLEMS OF VFT TO BE SOLVED 92

2.9 SUMMARY 93

REFERENCES 94

3 BASIC EQUATION AND SIMULATION MODEL OF VARIABLE FREQUENCY TRANSFORMER 97

3.1 OVERVIEW 97

3.2 STEADY STATE EQUATION AND POWER FLOW CALCULATION MODEL OF VFT 101

3.3 ELECTROMECHANICAL TRANSIENT EQUATION AND SIMULATION MODEL OF VFT 108

3.4 ELECTROMAGNETIC TRANSIENT EQUATION AND SIMULATION MODEL OF VFT 115

3.5SHORT-CIRCUIT IMPEDANCE AND CALCULATION MODEL OF VFT 118

3.6 VFT SIMULATION MODEL AVAILABILITY VERIFICATION 120

3.7 SUMMARY 125

REFERENCE 125

4 VFT CONTROL SYSTEM RESEARCH AND MODELING 127

4.1 OVERVIEW 127

4.2 VFT CONTROL STRATEGY AND SYSTEM BLOCK DIAGRAM 128

4.3 VFT ELEMENT LEVEL CONTROL AND DC DRIVE SYSTEM DESIGN 132

4.4 VFT DEVICE LEVEL CONTROL DESIGN 137

4.5 VFT SYSTEM LEVEL CONTROL DESIGN 142

4.6 SUMMARY 144

REFERENCE 144

5 ANALYSIS OF OPERATION CHARACTERISTICS AND APPLICATION OF VFT IN THE ELECTRICAL POWER SYSTEM 146

5.1 OVERVIEW 146

5.2 VFT PARAMETERS AND RESEARCH SYSTEM DESIGN 146

5.3 STARTUP AND POWER REGULATION OF VFT 151

5.4 USING VFT TO REGULATE SYSTEM POWER FLOW 157

5.5 CHARACTERISTICS OF VFT DURING FAULT PERIOD 160

5.6 USING VFT TO REGULATE SYSTEM FREQUENCY 163

5.7 USING VFT TO SUPPLY POWER TO WEAK POWER GRIDS AND PASSIVE SYSTEMS 165

5.8 APPLICATION OF VFT IN LARGE COMPLEX ELECTRICAL POWER SYSTEM 167

5.9 USING VFT TO SUPPRESS LOW FREQUENCY POWER OSCILLATION IN THE ELECTRICAL POWER SYSTEM 171

5.10 SUMMARY 172

REFERENCE 173

6 DESIGN OF ADAPTIVE LOW-FREQUENCY OSCILLATION DAMPING CONTROLLER BASED ON VFT 175

6.1 OVERVIEW 175

6.2 IMPACTS OF THE VARIABLE-FREQUENCY OSCILLATIONS OF POWER SYSTEMS AND CORRESPONDING CONTROL ACTIONS 175

6.3 PRONY METHOD BASED TRANSFER FUNCTION IDENTIFICATION 177

6.4 LOW-FREQUENCY OSCILLATION DAMPING CONTROLLER DESIGN WITH VFTS AND A PRONY METHOD 179

6.5 APPLICATION OF VFTS BASED ADAPTIVE DAMPING CONTROLLER IN A FOUR-GENERATOR POWER SYSTEM 181

6.6 APPLICATION OF VFT BASED ADAPTIVE DAMPING CONTROLLERS IN COMPLICATED POWER SYSTEMS 192

6.7 SUMMARY 196

7 TECHNICAL AND ECONOMICAL CHARACTERISTICS OF VFTS 199

7.1 OVERVIEW 199

7.2 COMPARISON OF TECHNICAL AND ECONOMICAL CHARACTERISTICS OF VFTS AND PHASE SHIFTING TRANSFORMERS 199

7.3 COMPARISON OF TECHNICAL AND ECONOMICAL CHARACTERISTICS BETWEEN VFTS AND DC TRANSMISSION SYSTEMS 210

7.4. SUMMARY 224

REFERENCES 224

8 SUMMARY AND PROSPECT 227

8.1 OVERVIEW 227

8.2 MAIN CONCLUSIONS 227

8.3 IN-DEPTH STUDIES OF VFTS 230

APPENDIX A 232

APPLICATION OF VFTS IN PROJECTS 232

A.1 OVERVIEW 232

A.2 MAIN STRUCTURE AND SYSTEMATIC CONTROL OF A VFT 232

A.3 THE WORLD FIRST VFT STATION ¢"¢"LANGLOIS SUBSTATION 239

A.4 THE WORLD SECOND VFT STATION¢"¢"LAREDO SUBSTATION 244

A.5 THE WORLD THIRD VFT STATION¢"¢"LINDEN SUBSTATION 245

REFERENCES 248

INDEX 249