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Advanced Control of AC / DC Power Networks: System of Systems Approach Based on Spatio-temporal Scales

Advanced Control of AC / DC Power Networks: System of Systems Approach Based on Spatio-temporal Scales

Abdelkrim Benchaib

ISBN: 978-1-119-13577-7

Aug 2015, Wiley-ISTE

164 pages

£81.99

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Description

The power engineering domain is facing huge challenges, with an increasing interest in intermittent renewable energies which are imposing major technical limitations. Operating ever closer to their limits, the industry-standard AC power grids are subject to instabilities.

This book presents an insight into DC grid systems, offering interesting issues to well controlled power grids, in contrast to current AC systems which provide the simplest and most economic connection method for short distances.

FOREWORD ix

PREFACE xi

LIST OF FIGURES xiii

LIST OF TABLES xvii

INTRODUCTION xix

CHAPTER 1. MODELING CONTROL OF VSCS 1

1.1. Introduction 1

1.2. Steady state voltage control systems – multi-terminal direct current (VSC-MTDC) model 3

1.2.1. Convention 4

1.2.2. DC side model 5

1.2.3. DC power flow calculation 5

1.2.4. AC side model 6

1.3. Control system of VSC based on VOC 8

1.3.1. Inner current controller 10

1.3.2. Outer power controller 11

1.3.3. DC voltage controller 13

1.4. Conclusion 15

CHAPTER 2. TIME SCALE TOOLS: A CONTROL SOLUTION FOR MTDC COMPLEX SYSTEMS WITH PLUG-AND-PLAY REQUIREMENTS 17

2.1. Introduction 17

2.2. Recalling VSC-HVDC control objectives 18

2.3. DC voltage control strategies for MTDC grids 20

2.3.1. Slack bus control (master/slave control) 21

2.3.2. Voltage margin control 22

2.3.3. Droop control 24

2.3.4. Dead-band-droop control 28

2.3.5. Undead-band-droop-control 29

2.3.6. Priority control 30

2.3.7. Ratio control 30

2.3.8. DC voltage control strategy summary 31

2.4. DC grid steady state modeling 32

2.5. Newton–Raphson technique 35

2.6. DC power flow 36

2.6.1. The first method: for master/slave control strategy 37

2.6.2. The second method (for a droop control): generalized approach 42

2.6.3. Generalized power flow for multi-terminal DC grids with more than one slack bus 45

2.7. Steady state control of multi-terminal DC grids 45

2.7.1. Normal operation (without fault) 46

2.7.2. Power-step-change with master/slave strategy of control 48

2.7.3. Voltage margin control 49

2.7.4. Power-step-change for a voltage/power droop control 51

2.8. Primary and secondary control strategies 52

2.9. Dynamic control of multi-terminal DC grids 54

2.10. Plug-and-play in interconnected systems: application to MTDC grids 55

2.11. Control of the actuators connected to the power system 55

2.12. Concluding remarks 56

CHAPTER 3. FROM SMALL SIGNAL TO EXACT LINEARIZATION OF SWING EQUATIONS 57

3.1. Introduction 57

3.2. Recalling stability analysis tools 62

3.2.1. Small signal analysis – first method of Lyapunov 63

3.2.2. Transient stability 63

3.2.3. Global stability 66

3.2.4. Summary of stability approaches 66

3.3. Modeling of AC power network – swing equation 67

3.3.1. Nonlinear swing equation 68

3.3.2. Linearized swing equation 70

3.3.3. Development of the electrical power term 72

3.4. Simulation of AC swing equation 74

3.4.1. Post-fault simulation case (transient response) 77

3.5. Revisited swing equation for multi-machines power system modeling 82

3.6. Exact linearization of swing equation 83

3.7. Concluding remarks 85

CHAPTER 4. SPACE SCALE PROPERTIES FOR AC/DC POWER NETWORK CONTROL AND OPERATIONS: NEW AGGREGATION METHODS IN POWER SYSTEMS 87

4.1. Introduction 87

4.2. Inter-area oscillation damping: locally intelligent substation 88

4.3. Free of space-scale model for AC systems: model reduction 92

4.3.1. Average model for N station multi-terminal systems: aggregated power system 92

4.3.2. Free of space-scale model for inter-region application 94

4.4. Modeling of DC power networks 99

4.4.1. Mathematical approach of two terminal DC grid modeling 99

4.4.2. Multi-terminal DC (MTDC) grid modeling: generalized MTDC model 101

4.4.3. Toward DC swing equation 102

4.4.4. Development of the electric power term Pe 104

4.4.5. AC and DC “swing equations” equivalence 104

4.5. AC/DC converter control to mimic synchronous generators 105

4.6. Concluding remarks 107

CONCLUSION 109

APPENDICES 113

APPENDIX 1 115

APPENDIX 2 117

APPENDIX 3 121

BIBLIOGRAPHY 123

INDEX 129