Wind Energy Generation: Modelling and Control

OLIMPO ANAYA-LARA, University Of Strathclyde, Glasgow, UKNICK JENKINS, Cardiff University. UK JANAKA EKANAYAKE, Cardiff University, UK PHILL CARTWRIGHT, Rolls-Royce plc. UK MIKE HUGHES, Consultant and Imperial College London, UK

• About the Authors xiPreface xiiiAcronyms and Symbols xv1 Electricity Generation from Wind Energy 11.1 Wind Farms 21.2 Wind Energy-generating Systems 31.2.1 Wind Turbines 31.2.2 Wind Turbine Architectures 71.3 Wind Generators Compared with Conventional Power Plant 101.3.1 Local Impacts 111.3.2 System-wide Impacts 131.4 Grid Code Regulations for the Integration of Wind Generation 14References 172 Power Electronics for Wind Turbines 192.1 Soft-starter for FSIG Wind Turbines 212.2 Voltage Source Converters (VSCs) 212.2.1 The Two-level VSC 212.2.2 Square-wave Operation 242.2.3 Carrier-based PWM (CB-PWM) 252.2.4 Switching Frequency Optimal PWM (SFO-PWM) 272.2.5 Regular and Non-regular Sampled PWM (RS-PWM and NRS-PWM) 282.2.6 Selective Harmonic Elimination PWM (SHEM) 292.2.7 Voltage Space Vector Switching (SV-PWM) 302.2.8 Hysteresis Switching 332.3 Application of VSCs for Variable-speed Systems 332.3.1 VSC with a Diode Bridge 342.3.2 Back-to-Back VSCs 34References 363 Modelling of Synchronous Generators 393.1 Synchronous Generator Construction 393.2 The Air-gap Magnetic Field of the Synchronous Generator 393.3 Coil Representation of the Synchronous Generator 423.4 Generator Equations in the dq Frame 443.4.1 Generator Electromagnetic Torque 473.5 Steady-state Operation 473.6 Synchronous Generator with Damper Windings 493.7 Non-reduced Order Model 513.8 Reduced-order Model 523.9 Control of Large Synchronous Generators 533.9.1 Excitation Control 533.9.2 Prime Mover Control 55References 564 Fixed-speed Induction Generator (FSIG)-based Wind Turbines 574.1 Induction Machine Construction 574.1.1 Squirrel-cage Rotor 584.1.2 Wound Rotor 584.2 Steady-state Characteristics 584.2.1 Variations in Generator Terminal Voltage 614.3 FSIG Configurations for Wind Generation 614.3.1 Two-speed Operation 624.3.2 Variable-slip Operation 634.3.3 Reactive Power Compensation Equipment 644.4 Induction Machine Modelling 644.4.1 FSIG Model as a Voltage Behind a Transient Reactance 654.5 Dynamic Performance of FSIG Wind Turbines 704.5.1 Small Disturbances 704.5.2 Performance During Network Faults 73References 765 Doubly Fed Induction Generator (DFIG)-based Wind Turbines 775.1 Typical DFIG Configuration 775.2 Steady-state Characteristics 775.2.1 Active Power Relationships in the Steady State 805.2.2 Vector Diagram of Operating Conditions 815.3 Control for Optimum Wind Power Extraction 835.4 Control Strategies for a DFIG 845.4.1 Current-mode Control (PVdq) 845.4.2 Rotor Flux Magnitude and Angle Control 895.5 Dynamic Performance Assessment 905.5.1 Small Disturbances 915.5.2 Performance During Network Faults 94References 966 Fully Rated Converter-based (FRC) Wind Turbines 996.1 FRC Synchronous Generator-based (FRC-SG) Wind Turbine 1006.1.1 Direct-driven Wind Turbine Generators 1006.1.2 Permanent Magnets Versus Electrically Excited Synchronous Generators 1016.1.3 Permanent Magnet Synchronous Generator 1016.1.4 Wind Turbine Control and Dynamic Performance Assessment 1036.2 FRC Induction Generator-based (FRC-IG) Wind Turbine 1136.2.1 Steady-state Performance 1136.2.2 Control of the FRC-IG Wind Turbine 1146.2.3 Performance Characteristics of the FRC-IG Wind Turbine 119References 1197 Influence of Rotor Dynamics on Wind Turbine Operation 1217.1 Blade Bending Dynamics 1227.2 Derivation of Three-mass Model 1237.2.1 Example: 300 kW FSIG Wind Turbine 1247.3 Effective Two-mass Model 1267.4 Assessment of FSIG and DFIG Wind Turbine Performance 128Acknowledgement 132References 1328 Influence of Wind Farms on Network Dynamic Performance 1358.1 Dynamic Stability and its Assessment 1358.2 Dynamic Characteristics of Synchronous Generation 1368.3 A Synchronizing Power and Damping Power Model of a Synchronous Generator 1378.4 Influence of Automatic Voltage Regulator on Damping 1398.5 Influence on Damping of Generator Operating Conditions 1418.6 Influence of Turbine Governor on Generator Operation 1438.7 Transient Stability 1458.8 Voltage Stability 1478.9 Generic Test Network 1498.10 Influence of Generation Type on Network Dynamic Stability 1508.10.1 Generator 2 – Synchronous Generator 1518.10.2 Generator 2 – FSIG-based Wind Farm 1528.10.3 Generator 2 – DFIG-based Wind Farm (PVdq Control) 1528.10.4 Generator 2 – DFIG-based Wind Farm (FMAC Control) 1528.10.5 Generator 2 – FRC-based Wind Farm 1528.11 Dynamic Interaction of Wind Farms with the Network 1538.11.1 FSIG Influence on Network Damping 1538.11.2 DFIG Influence on Network Damping 1588.12 Influence of Wind Generation on Network Transient Performance 1618.12.1 Generator 2 – Synchronous Generator 1618.12.2 Generator 2 – FSIG Wind Farm 1628.12.3 Generator 2 – DFIG Wind Farm 1638.12.4 Generator 2 – FRC Wind Farm 165References 1659 Power Systems Stabilizers and Network Damping Capability of Wind Farms 1679.1 A Power System Stabilizer for a Synchronous Generator 1679.1.1 Requirements and Function 1679.1.2 Synchronous Generator PSS and its Performance Contributions 1699.2 A Power System Stabilizer for a DFIG 1729.2.1 Requirements and Function 1729.2.2 DFIG-PSS and its Performance Contributions 1789.3 A Power System Stabilizer for an FRC Wind Farm 1829.3.1 Requirements and Functions 1829.3.2 FRC–PSS and its Performance Contributions 186References 19110 The Integration of Wind Farms into the Power System 19310.1 Reactive Power Compensation 19310.1.1 Static Var Compensator (SVC) 19410.1.2 Static Synchronous Compensator (STATCOM) 19510.1.3 STATCOM and FSIG Stability 19710.2 HVAC Connections 19810.3 HVDC Connections 19810.3.1 LCC–HVDC 20010.3.2 VSC–HVDC 20110.3.3 Multi-terminal HVDC 20310.3.4 HVDC Transmission – Opportunities and Challenges 20410.4 Example of the Design of a Submarine Network 20710.4.1 Beatrice Offshore Wind Farm 20710.4.2 Onshore Grid Connection Points 20810.4.3 Technical Analysis 21010.4.4 Cost Analysis 21210.4.5 Recommended Point of Connection 213Acknowledgement 214References 21411 Wind Turbine Control for System Contingencies 21711.1 Contribution of Wind Generation to Frequency Regulation 21711.1.1 Frequency Control 21711.1.2 Wind Turbine Inertia 21811.1.3 Fast Primary Response 21911.1.4 Slow Primary Response 22211.2 Fault Ride-through (FRT) 22811.2.1 FSIGs 22811.2.2 DFIGs 22911.2.3 FRCs 23111.2.4 VSC–HVDC with FSIG Wind Farm 23311.2.5 FRC Wind Turbines Connected Via a VSC–HVDC 234References 237Appendix A: State–Space Concepts and Models 241Appendix B: Introduction to Eigenvalues and Eigenvectors 249Appendix C: Linearization of State Equations 255Appendix D: Generic Network Model Parameters 259Index 265