Grid Integration of Wind Energy

Professor Siegfried Heier, Universitaet Kassel, Institut fuer Elektrische Energietechnik, GermanySiegfried Heier is currently the Head of the Wind Engineering department at Kassel University, Germany. He has been a Professor at the university since 1979. He is the initiator and head of many research projects in the field of wind engineering and he has published more than 70 articles about generator systems, and control and grid integration of wind energy converts. Professor Heier has also written books in the area, such as Windkraftanlagen (B.G. Teubner), now in its 5th Edition. Siegfried currently holds two patents.

• Preface xiNotation xiii1 Wind Energy Power Plants 11.1 Wind Turbine Structures 11.2 A Brief History 41.3 Milestones of Development 51.4 Functional Structures of Wind Turbines 20References 302 Wind Energy Conversion Systems 312.1 Drive Torque and Rotor Power 312.1.1 Inputs and outputs of a wind turbine 312.1.2 Power extraction from the airstream 322.1.3 Determining power or driving torque by the blade element method 342.1.4 Simplifying the computation method 382.1.5 Modeling turbine characteristics 402.2 Turbines 462.2.1 Hub and turbine design 502.2.2 Rotor blade geometry 512.3 Power Control by Turbine Manipulation 572.3.1 Turbine yawing 572.3.2 Rotor blade pitch variation 672.3.3 Limiting power by stall control 972.3.4 Power control using speed variation 1002.4 Mechanical Drive Trains 1022.5 System Data of a Wind Power Plant 1082.5.1 Turbine and drive train data 1082.5.2 Machine and tower masses 1102.5.3 Machine costs 111References 1163 Generating Electrical Energy from Mechanical Energy 1193.1 Constraints and Demands on the Generator 1193.2 Energy Converter Systems 1223.2.1 Asynchronous generator construction 1253.2.2 Synchronous generator construction 1263.3 Operational Ranges of Asynchronous and Synchronous Machines 1263.4 Static and Dynamic Torque 1323.4.1 Static torque 1333.4.2 Dynamic torque 1473.5 Generator Simulation 1543.5.1 Synchronous machines 1553.5.2 Asynchronous machines 1603.6 Design Aspects 1613.6.1 Asynchronous generators 1623.6.2 Synchronous generators for gearless plants 1743.6.3 Multi-generator concept (Dissertation A. Ezzahraoui) 1873.6.4 Ring generator with magnetic bearings (Dissertation K. Messol) 1943.6.5 Compact superconductive and other new generator concepts 1973.7 Machine Data 1993.7.1 Mass and cost relationships 2003.7.2 Characteristic values of asynchronous machines 2023.7.3 Characteristic values of synchronous machines 204References 2084 The Transfer of Electrical Energy to the Supply Grid 2104.1 Power Conditioning and Grid Connection 2104.1.1 Converter systems 2124.1.2 Power semiconductors for converters 2154.1.3 Functional characteristics of power converters 2184.1.4 Converter designs 2224.1.5 Indirect converter 2234.1.6 Electromagnetic compatibility (EMC) 2364.1.7 Protective measures during power conditioning 2374.2 Grid Protection 2384.2.1 Fuses and grid disconnection 2394.2.2 Short-circuiting power 2394.2.3 Increase of short-circuit power 2424.2.4 Isolated operation and rapid auto-reclosure 2454.2.5 Overvoltages in the event of grid faults 2474.3 Grid Effects 2474.3.1 General compatibility and interference 2474.3.2 Output behavior of wind power plants 2484.3.3 Voltage response in grid supply 2604.3.4 Harmonics and subharmonics 2714.3.5 Voltage faults and the fault-ride-through (FRT) 2794.4 Resonance Effects in the Grid During Normal Operation 2844.5 Remedial Measures against Grid Effects and Grid Resonances 2904.5.1 Filters 2904.5.2 Filter design 2924.5.3 Function of harmonic absorber filters and compensation units 2934.5.4 Grid-specific filter layout 2944.5.5 Utilizing compensating effects 2974.6 Grid Control and Protection 3004.6.1 Supply by wind turbines 3004.6.2 Grid support and grid control with wind turbines and other renewable systems 3014.6.3 Central reactive power control 3054.6.4 System services and operation 3084.6.5 Connection of wind turbine to the transmission grid 3104.7 Grid Connection Rules 3114.8 Grid Connection in the Offshore Region 3174.8.1 Offshore wind farm properties 3174.8.2 Stationary and dynamic behavior of offshore wind farms 3194.8.3 Wind farm and cluster formation at sea and grid connection 3194.8.4 Electrical energy transmission to the mainland 3234.8.5 Reactive power requirement and reactive power provision in the offshore grid 3254.8.6 Flexible AC transmission systems (FACTS) 3304.9 Integration of the Wind Energy into the Grid and Provision of Energy 3334.9.1 Grid extension 3334.9.2 Provision of energy 3354.9.3 Control and reserve power 3374.9.4 Power reserve provision with wind farms (Dissertation A. J. Gesino) 3384.9.5 Intercontinental grid connections 346References 3465 Control and Supervision of Wind Turbines 3555.1 System Requirements and Operating Modes 3565.2 Isolated Operation of Wind Turbines 3585.2.1 Turbines without a blade pitch adjustment mechanism 3595.2.2 Plants with a blade pitch adjustment mechanism 3605.2.3 Plants with load management 3625.2.4 Turbine control by means of a bypass 3625.3 Grid Operation of Wind Turbines 3635.4 Control Concepts 3675.4.1 Control in isolated operation 3675.4.2 Regulation of variable-speed turbines 3715.4.3 Regulation of variable-slip asynchronous generators 3735.4.4 Regulation of turbines with a rigid connection to the grid 3885.4.5 Wind turbine control using hydrodynamic variable-speed superimposing gears 3905.5 Controller Design 3905.5.1 Adjustment processes and torsional moments at the rotor blades 3925.5.2 Standardizing and linearizing the variables 3955.5.3 Control circuits and simplified dimensioning 4005.5.4 Improving the control characteristics 4045.5.5 Control design for wind turbines 4105.6 Management System 4115.6.1 Operating states 4125.6.2 Faults 4235.6.3 Determining the state of system components 4245.7 Monitoring and Safety Systems 4245.7.1 Wind measuring devices 4255.7.2 Oscillation monitoring 4255.7.3 Grid surveillance and lightning protection 4265.7.4 Surveillance computer 4265.7.5 Fault prediction 4275.7.6 Voltage limitation 429References 4306 Using Wind Energy 4366.1 Wind Conditions and Energy Yields 4366.1.1 Global wind conditions 4366.1.2 Local wind conditions and annual available power from the wind 4386.1.3 Calculation of site-specific and regional turbine yields 4406.1.4 Wind atlas methods 4446.2 Potential and Expansion 4496.2.1 Wind energy use on land 4496.2.2 Offshore wind energy use 4516.2.3 Repowering 4536.3 Economic Considerations 4556.3.1 Purchase and maintenance costs 4576.3.2 Power supply and financial yields 4576.3.3 Blue section 4606.3.4 Commercial calculation methods 4616.4 Legal Aspects and the Installation of Turbines 4636.4.1 Immission protection 4646.4.2 Nature and landscape conservation 4676.4.3 Building laws 4686.4.4 Planning and planning permission 4696.4.5 Procedure for erecting a wind turbine 4706.4.6 Offshore utilization of wind energy 4726.5 Ecological Balance 4746.5.1 Contribution to climate protection 4746.5.2 Landscape utilization 4756.5.3 Bird strike 4756.5.4 Bats 4756.5.5 Recycling of wind turbines 4756.5.6 Energetic amortization time and harvest factor 476References 476Index 483