Wind Energy Handbook

by Burton, Tony L.; Jenkins, Nick; Bossanyi, Ervin; Sharpe, David; Graham, Michael

• ISBN13: 9781119451099
• ISBN10: 1119451094
• Edition: 3rd
• Format: Hardcover
• Copyright: 2021-04-19
• Publisher: Wiley

Summary

Fully updated and authoritative reference to wind energy technology written by leading academic and industry professionals

The newly revised Third Edition of the Wind Energy Handbook delivers a fully updated treatment of key developments in wind technology since the publication of the book's Second Edition in 2011. The criticality of wakes within wind farms is addressed by the addition of an entirely new chapter on wake effects, including 'engineering' wake models and wake control. Offshore, attention is focused for the first time on the design of floating support structures, and the new 'PISA' method for monopile geotechnical design is introduced.

The coverage of blade design has been completely rewritten, with an expanded description of laminate fatigue properties and new sections on manufacturing methods, blade testing, leading-edge erosion and bend-twist coupling. These are complemented by new sections on blade add-ons and noise in the aerodynamics chapters, which now also include a description of the Leishman-Beddoes dynamic stall model and an extended introduction to Computational Fluid Dynamics analysis.

The importance of the environmental impact of wind farms both on- and offshore is recognized by expanded coverage, and the requirements of the Grid Codes to ensure wind energy plays its full role in the power system are described. The conceptual design chapter has been extended to include a number of novel concepts, including low induction rotors, multiple rotor structures, superconducting generators and magnetic gearboxes.

References and further reading resources are included throughout the book and have been updated to cover the latest literature. As in previous editions, the core subjects constituting the essential background to wind turbine and wind farm design are covered. These include:

• The nature of the wind resource, including geographical variation, synoptic and diurnal variations, and turbulence characteristics
• The aerodynamics of horizontal axis wind turbines, including the actuator disc concept, rotor disc theory, the vortex cylinder model of the actuator disc and the Blade-Element/Momentum theory
• Design loads for horizontal axis wind turbines, including the prescriptions of international standards
• Alternative machine architectures
• The design of key components
• Wind turbine controller design for fixed and variable speed machines
• The integration of wind farms into the electrical power system
• Wind farm design, siting constraints, and the assessment of environmental impact

Perfect for engineers and scientists learning about wind turbine technology, the Wind Energy Handbook will also earn a place in the libraries of graduate students taking courses on wind turbines and wind energy, as well as industry professionals whose work requires a deep understanding of wind energy technology.

Author Biography

Tony Burton is a Civil Engineer recently retired from a post in offshore wind turbine support structure design with DNV GL in London, UK. He has worked for a major UK wind turbine manufacturer on the design, construction, commissioning, and operation of both medium and large-scale wind turbines. 

Nick Jenkins is Professor of Renewable Energy at Cardiff University. He has over 14 years of industrial experience and is a Fellow of the IET, IEEE, and Royal Academy of Engineering. 

Ervin Bossanyi is Senior Principal Researcher in renewables at DNV GL in Bristol, United Kingdom. He is also Visiting Professor at the University of Bristol. He received the Scientific Award of the European Academy of Wind Energy for outstanding contributions to the development of wind energy. 

David Sharpe is a Researcher in wind turbine aerodynamics, having previously been Senior Lecturer in aeronautical engineering at Queen Mary College and then Senior Research Fellow at the Centre for Renewable Energy Systems Technology at Loughborough University. He is currently a visiting Professor at Strathclyde University. 

Michael Graham is Professor in the Faculty of Engineering, Department of Aeronautics at Imperial College in London, UK. His research foci are on environmental flows, computational fluid dynamics, and marine technology. 

Table of Contents

About the Authors

Preface to Second Edition

Preface to Third Edition

Acknowledgements for First Edition

Acknowledgements for Second Edition

Acknowledgements for Third Edition

List of Symbols

Figures C1 and C2 – Co-ordinate Systems

1. Introduction

1.1. Historical development of wind energy

1.2. Modern wind turbines

1.3. Scope of the book

References

Websites

Further reading

2. The wind resource

2.1. The nature of the wind

2.2. Geographical variation in the wind resource

2.3. Long-term wind speed variations

2.4. Annual and seasonal variations

2.5. Synoptic and diurnal variations

2.6. Turbulence

2.6.1. The nature of turbulence

2.6.2. The boundary layer

2.6.3. Turbulence intensity

2.6.4. Turbulence spectra

2.6.5. Length scales and other parameters

2.6.6. Asymptotic limits

2.6.7. Cross-spectra and coherence functions

2.6.8. The Mann model of turbulence

2.7. Gust wind speeds

2.8. Extreme wind speeds

2.8.1. Extreme winds in standards

2.9. Wind speed prediction and forecasting

2.9.1. Statistical methods

2.9.2. Meteorological methods

2.9.3. Current methods

2.10. Turbulence in complex terrain

References

3. Aerodynamics of horizontal axis wind turbines (title followed by “Author’s note on aerodynamics”)

3.1. Introduction

3.2. The actuator disc concept

3.2.1. Simple momentum theory

3.2.2. Power coefficient

3.2.3. The Betz limit

3.2.4. The thrust coefficient

3.3. Rotor disc theory

3.3.1. Wake rotation

3.3.2. Angular momentum theory

3.3.3. Maximum power

3.4. Vortex cylinder model of the actuator disc

3.4.1. Introduction

3.4.2. Vortex cylinder theory

3.4.3. Relationship between bound circulation and the induced velocity

3.4.4. Root vortex

3.4.5. Torque and power

3.4.6. Axial flow field

3.4.7. Tangential flow field

3.4.8. Axial thrust

3.4.9. Radial flow and the general flow field

3.4.10. Further development of the Actuator Model

3.4.11. Conclusions

3.5. Rotor blade theory (blade-element/momentum theory)

3.5.1. Introduction

3.5.2. Blade element theory

3.5.3. The blade-element/momentum (BEM) theory

3.5.4. Determination of rotor torque and power

3.6. Actuator Line Theory, including radial variation

3.7. Breakdown of the momentum theory

3.7.1. Free-stream/wake mixing

3.7.2. Modification of rotor thrust caused by flow separation

3.7.3. Empirical determination of thrust coefficient

3.8. Blade geometry

3.8.1. Introduction

3.8.2. Optimal design for variable speed operation

3.8.3. A simple blade design

3.8.4. Effects of drag on optimal blade design

3.8.5. Optimal blade design for constant speed operation

3.9. The effects of a discrete number of blades

3.9.1. Introduction

3.9.2. Tip-losses

3.9.3. Prandtl’s approximation for the tip-loss factor

3.9.4. Blade root losses

3.9.5. Effect of tip-loss on optimum blade design and power

3.9.6. Incorporation of tip-loss for non-optimal operation

3.9.7. Alternative explanation for tip-loss

3.10. Stall delay

3.11. Calculated results for an actual turbine

3.12. The performance curves

3.12.1. Introduction

3.12.2. The CP − λ performance curve

3.12.3. The effect of solidity on performance

3.12.4. The CQ − λ curve

3.12.5. The CT − λ curve

3.13. Constant rotational speed operation

3.13.1. Introduction

3.13.2. The KP − 1/λ curve

3.13.3. Stall regulation

3.13.4. Effect of rotational speed change

3.13.5. Effect of blade pitch angle change

3.14. Pitch regulation

3.14.1. Introduction

3.14.2. Pitching to stall

3.14.3. Pitching to feather

3.15. Comparison of measured with theoretical performance

3.16. Variable speed operation

3.17. Estimation of energy capture

3.18. Wind turbine aerofoil design

3.18.1. Introduction

3.18.2. The NREL aerofoils

3.18.3. The Risø aerofoils

3.18.4. The Delft aerofoils

3.18.5. General principles for outboard and inboard blade sections

3.19. Add-ons (including blade modifications independent of the main structure)

3.19.1. Devices to control separation and stalling vortex generators (VGs)

3.19.2. Devices to increase CLmax and Lift/Drag ratio

3.19.3. Circulation control (Jet flaps)

3.20. Aerodynamic noise

3.20.1. Noise sources

3.20.2. Inflow turbulene-induced blade noise

3.20.3. Self-induced blade noise

3.20.4. Interaction between turbulent boundary layers on the blade and the trailing edge

3.20.5. Other blade noise sources

3.20.6. Summary

References

Websites

Further reading

Appendix A3 Lift and drag of aerofoils

A3.1 Drag

A3.2 The boundary layer

A3.3 Boundary layer separation

A3.4 Laminar and turbulent boundary layers

A3.5 Definition of lift and its relationship to circulation

A3.6 The stalled aerofoil

A3.7 The lift coefficient

A3.8 Aerofoil drag characteristics

A3.8.1 Symmetric aerofoils

A3.8.2k Cambered aerofoils

4. Further aerodynamic topics for wind turbines

4.1. Introduction

4.2. The aerodynamics of turbines in steady yaw

4.2.1. Momentum theory for a turbine rotor in steady yaw

4.2.2. Glauert’s momentum theory for the yawed rotor

4.2.3. Vortex cylinder model of the yawed actuator disc

4.2.4. Flow expansion

4.2.5. Related theories

4.2.6. Wake rotation for a turbine rotor in steady yaw

4.2.7. The blade element theory for a turbine rotor in steady yaw

4.2.8. The blade element – momentum theory for a rotor in steady yaw

4.2.9. Calculated values of induced velocity

4.2.10. Blade forces for a rotor in steady yaw

4.2.11. Yawing and tilting moments in steady yaw

4.3. The circular wing/rotor model

4.3.1. Introduction

4.3.2. The general pressure distribution theory of Kinner

4.3.3. The axi-symmetric pressure distributions

4.3.4. The anti-symmetric pressure distributions

4.3.5. The Pitt and Peters model

4.3.6. The general acceleration potential method

4.3.7. Comparison of methods

4.4. Unsteady flow

4.4.1. Introduction

4.4.2. The acceleration potential method to analysek unsteady flow

4.4.3. Unsteady yawing and tilting moments

4.5. Unsteady aerofoil aerodynamics

4.5.1. Introduction

4.5.2. Aerodynamic forces caused by aerofoil acceleration

4.5.3. The effect of the shed vortex wake on an aerofoil in unsteady flow

4.6. Dynamic stall

4.6.1. Introduction

4.6.2. Dynamic stall models

4.6.2.1. The Leishmann-Beddoes (LB) Model

4.6.2.2. The ONERA model

4.6.2.3. The Gangwani Model

4.7. Computational fluid dynamics

4.7.1. Introduction

4.7.2. Inviscid computational methods

4.7.3. RANS and URANS CFD methods

4.7.4. LES and DES methods

4.7.5. Numerical techniques for CFD

4.7.5.1. Inviscid flow

4.7.5.2. Viscous flow (primitive variable methods)

4.7.6. Methods of approximating the terms in the NS equations over the flow field

4.7.6.1. The Finite Difference (FD) method

4.7.6.2. Finite Volume Method (FVM)

4.7.6.3. Finite Element Method (FEM)

4.7.7. Grid construction

4.7.8. Full Flow Field Simulation including ABL and wind turbines

4.7.8.1. Incident Flow Field (ABL)

4.7.8.2. Large scale wind farm simulation

References

Bibliography

5. Design loads for horizontal axis wind turbines

5.1. National and international standards

5.1.1. Historical development

5.1.2. IEC 61400–1

5.2. Basis for design loads

5.2.1. Sources of loading

5.2.2. Ultimate loads

5.2.3. Fatigue loads

5.2.4. Partial safety factors

5.2.5. Functions of the control and safety systems

5.3. Turbulence and wakes

5.4. Extreme loads

5.4.1. Operational load cases

5.4.2. Non-operational load cases

5.4.3. Blade/tower clearance

5.4.4. Constrained stochastic simulation of wind gusts

5.5. Fatigue loading

5.5.1. Synthesis of fatigue load spectrum

5.6. Stationary blade loading

5.6.1. Lift and drag coefficients

5.6.2. Critical configuration for different machine types

5.6.3. Dynamic response

5.7. Blade loads during operation

5.7.1. Deterministic and stochastic load components

5.7.2. Deterministic aerodynamic loads

5.7.3. Gravity loads

5.7.4. Deterministic inertia loads

5.7.5. Stochastic aerodynamic loads: analysis in the frequency domain

5.7.6. Stochastic aerodynamic loads: analysis in the time domain

5.7.7. Extreme loads

5.8. Blade dynamic response

5.8.1. Modal analysis

5.8.2. Mode shapes and frequencies

5.8.3. Centrifugal stiffening

5.8.4. Aerodynamic and structural damping

5.8.5. Response to deterministic loads: step-by-step dynamic analysis

5.8.6. Response to stochastic loads

5.8.7. Response to simulated loads

5.8.8. Teeter motion

5.8.9. Tower coupling

5.8.10. Aeroelastic stability

5.9. Blade fatigue stresses 267

5.9.1. Methodology for blade fatigue design

5.9.2. Combination of deterministic and stochastic components

5.9.3. Fatigue prediction in the frequency domain

5.9.4. Wind simulation

5.9.5. Fatigue cycle counting

5.10. Hub and low speed shaft loading

5.10.1. Introduction

5.10.2. Deterministic aerodynamic loads

5.10.3. Stochastic aerodynamic loads

5.10.4. Gravity loading

5.11. Nacelle loading

5.11.1. Loadings from rotor

5.11.2. Nacelle wind loads

5.12. Tower loading

5.12.1. Extreme loads

5.12.2. Dynamic response to extreme loads

5.12.3. Operational loads due to steady wind (deterministic component)

5.12.4. Operational loads due to turbulence (stochastic component)

5.12.5. Dynamic response to operational loads

5.12.6. Fatigue loads and stresses

5.13. Wind turbine dynamic analysis codes

5.14. Extrapolation of extreme loads from simulations

5.14.1. Derivation of empirical cumulative distribution function of global extremes

5.14.2. Fitting an extreme value distribution to the empirical distribution

5.14.3. Comparison of extreme value distributions

5.14.4. Combination of probability distributions

5.14.5. Extrapolation

5.14.6. Fitting probability distribution after aggregation

5.14.7. Local extremes method

5.14.8. Convergence requirements

References

Appendix 5: Dynamic response of stationary blade in turbulent wind

A5.1 Introduction

A5.2 Frequency response function

A5.2.1 Equation of motion

A5.2.2 Frequency response function

A5.3 Resonant displacement response ignoring wind variations along the blade

A5.3.1 Linearisation of wind loading

A5.3.2 First mode displacement response

A5.3.3 Background and resonant response

A5.4 Effect of across-wind turbulence distribution on resonant displacement response

A5.4.1 Formula for normalised co-spectrum

A5.5 Resonant root bending moment

A5.6 Root bending moment background response

A5.7 Peak response

A5.8 Bending moments at intermediate blade positions

A5.8.1 Background response

A5.8.2 Resonant response

References

6. Conceptual design of horizontal axis wind turbines

6.1. Introduction

6.2. Rotor diameter

6.2.1. Cost modelling

6.2.2. Simplified cost model for machine size optimisation an illustration

6.2.3. The NREL cost model

6.2.4. The INNWINF.EU Cost Model

6.2.5. Machine size growth

6.2.6. Gravity limitations

6.2.7. Variable diameter rotors

6.3. Machine rating

6.3.1. Simplified cost model for optimising machine rating in relation to diameter

6.3.2. Relationship between optimum rated wind speed and annual mean

6.3.3. Specific power of production machines

6.4. Rotational speed

6.4.1. Ideal relationship between rotational speed and solidity

6.4.2. Influence of rotational speed on blade weight

6.4.3. High-speed rotors

6.4.4. Low induction rotors

6.4.5. Noise constraint on rotational speed

6.4.6. Visual considerations

6.5. Number of blades

6.5.1. Overview

6.5.2. Ideal relationship between number of blades, rotational speed and solidity

6.5.3. Effect of number of blades on optimum CP in the presence of tip loss and drag

6.5.4. Some performance and cost comparisons

6.5.5. Effect of number of blades on loads

6.5.6. Noise constraint on rotational speed

6.5.7. Visual appearance

6.5.8. Single-bladed turbines

6.6. Teetering

6.6.1. Load relief benefits

6.6.2. Limitation of large excursions

6.6.3. Pitch-teeter coupling

6.6.4. Teeter stability on stall-regulated machines

6.7. Power control

6.7.1. Passive stall control

6.7.2. Active pitch control

6.7.3. Passive pitch control

6.7.4. Active stall control

6.7.5. Yaw control

6.8. Braking systems

6.8.1. Independent braking systems: requirements of standards

6.8.2. Aerodynamic brake options

6.8.3. Mechanical brake options

6.8.4. Parking versus idling

6.9. Fixed speed, two speed or variable speed

6.9.1. Fixed speed operation

6.9.2. Two speed operation

6.9.3. Variable slip operation (see also Chapter 8, Section 8.3.8)

6.9.4. Variable speed operation

6.9.5. Generator system architectures

6.9.6. Low speed direct drive generators

6.9.7. Hybrid gearboxes, medium speed generators

6.9.8. Evolution of generator systems

6.10. Other drive trains and generators

6.10.1. Directly connected, fixed speed generators

6.10.2. Innovations to allow the use of directly connected generators

6.10.3. Generator and drive train innovations

6.11. Drive train mounting arrangement options

6.11.1. Low speed shaft mounting

6.11.2. High speed shaft and generator mounting

6.12. Drive train compliance

6.13. Rotor position with respect to tower

6.13.1. Upwind configuration

6.13.2. Downwind configuration

6.14. Tower stiffness

6.14.1. Stochastic thrust loading at blade passing frequency

6.14.2. Tower top moment fluctuations due to blade pitch errors

6.14.3. Tower top moment fluctuations due to rotor mass imbalance

6.14.4. Tower stiffness categories

6.15. Multiple rotor structures

6.15.1. Space frame support structure

6.15.2. Tubular cantilever arm support structure

6.15.3. Vestas four rotor array

6.15.4. Cost comparison based on fundamental scaling rules

6.15.5. Cost comparison based on NREL scaling indices

6.15.6. Discussion

6.16. Augmented flow

6.17. Personnel safety and access issues

References

7. Component design

7.1. Blades

7.1.1. Introduction

7.1.2. Aerodynamic design

7.1.3. Practical modifications to optimum aerodynamic design

7.1.4. Structural design criteria

7.1.5. Form of blade structure

7.1.6. Blade materials and properties

7.1.7. Static Properties of glass/polyester and glass/epoxy composites

7.1.8. Fatigue Properties of glass/polyester and glass/epoxy composites

7.1.9. Carbon fibre composites

7.1.10. Properties of wood laminates

7.1.11. Material safety factors

7.1.12. Manufacture of composite blades

7.1.13. Blade loading overview

7.1.14. Simplified fatigue design example

7.1.15. Blade resonance

7.1.16. Design against buckling

7.1.17. Blade root fixings

7.1.18. Blade testing

7.1.19. Leading edge erosion

7.1.20. Bend-twist coupling

7.2. Pitch bearings

7.3. Rotor hub

7.4. Gearbox

7.4.1. Introduction

7.4.2. Variable loading during operation

7.4.3. Drive train dynamics

7.4.4. Braking loads

7.4.5. Effect of variable loading on fatigue design of gear teeth

7.4.6. Effect of variable loading on fatigue design of bearings and shafts

7.4.7. Gear arrangements

7.4.8. Gearbox noise

7.4.9. Integrated gearboxes

7.4.10. Lubrication and cooling

7.4.11. Gearbox efficiency

7.5. Generator

7.5.1. Fixed-speed induction generators

7.5.2. Variable slip induction generators

7.5.3. Variable speed operation

7.5.4. Variable speed operation using a Doubly Fed Induction Generator (DFIG)

7.5.5. Variable speed operation using a Full Power Converter (FPG)

7.6. Mechanical brake

7.6.1. Brake duty

7.6.2. Factors governing brake design

7.6.3. Calculation of brake disc temperature rise

7.6.4. High speed shaft brake design

7.6.5. Two level braking

7.6.6. Low speed shaft brake design

7.7. Nacelle bedplate

7.8. Yaw drive

7.9. Tower

7.9.1. Introduction

7.9.2. Constraints on first mode natural frequency

7.9.3. Steel tubular towers

7.9.4. Steel lattice towers

7.10. Foundations

7.10.1. Slab foundations

7.10.2. Multi-pile foundations

7.10.3. Concrete monopile foundations

7.10.4. Foundations for steel lattice towers

7.10.5. Foundation rotational stiffness

References

8. The controller

8.1. Functions of the wind turbine controller

8.1.1. Supervisory control

8.1.2. Closed loop control

8.1.3. The safety system

8.2. Closed loop control: issues and objectives

8.2.1. Pitch control (See also Chapter 3, Section 3.14 and Chapter 6, Section 6.7.2)

8.2.2. Stall control

8.2.3. Generator torque control (see also Chapter 6, Section 6.9 and Chapter 7, Section 7.5)

8.2.4. Yaw control

8.2.5. Influence of the controller on loads

8.2.6. Defining controller objectives

8.2.7. PI and PID controllers

8.3. Closed loop control: general techniques

8.3.1. Control of fixed speed, pitch regulated turbines

8.3.2. Control of variable speed pitch regulated turbines

8.3.3. Pitch control for variable speed turbines

8.3.4. Switching between torque and pitch control

8.3.5. Control of tower vibration

8.3.6. Control of drive train torsional vibration

8.3.7. Variable speed stall regulation

8.3.8. Control of variable slip turbines

8.3.9. Individual pitch control

8.3.10. Multivariable control – decoupling the wind turbine control loops

8.3.11. Two-axis decoupling for individual pitch control

8.3.12. Load reduction with individual pitch control

8.3.13. Individual pitch control implementation

8.3.14. Further extensions to individual pitch control

8.3.15. Commercial use of individual pitch control

8.3.16. Estimation of rotor-average wind speed

8.3.17. LIDAR-assisted control

8.3.18. LIDAR signal processing

8.4. Closed loop control: analytical design methods

8.4.1. Classical design methods

8.4.2. Gain scheduling for pitch controllers

8.4.3. Adding more terms to the controller

8.4.4. Other extensions to classical controllers

8.4.5. Optimal feedback methods

8.4.6. Pros and cons of model-based control methods

8.4.7. Other methods

8.5. Pitch actuators (see also, Chapter 6 Section 6.7.2)

8.6. Control system implementation

8.6.1. Discretisation

8.6.2. Integrator desaturation

References

9. Wake effects and wind farm control

9.1. Introduction

9.2. Wake characteristics

9.2.1. Modelling wake effects

9.2.2. Wake turbulence in the IEC standard

9.2.3. CFD models

9.2.4. Simplified or ‘engineering’ wake models

9.2.5. Wind farm models

9.3. Active wake control methods

9.3.1. Wake control options

9.3.2. Control objectives

9.3.3. Control design methods for active wake control

9.3.4. Field testing for active wake control

9.4. Wind farm control and the grid system

9.4.1. Curtailment and delta control

9.4.2. Fast frequency response

10. Wind turbine installations and wind farms

10.1. Project development

10.1.1. Initial site selection

10.1.2. Project feasibility assessment

10.1.3. The Measure-Correlate-Predict (MCP) technique

10.1.4. Micrositing

10.1.5. Site investigations

10.1.6. Public consultation

10.1.7. Preparation and submission of the planning application and Environmental Statement

10.1.8. Planning requirements in the UK

10.1.9. Procurement of a wind farm

10.1.10. Financing of wind farms

10.2. Landscape and visual impact assessment

10.2.1. Landscape character assessment

10.2.2. Turbine and wind farm design for minimum visual impact

10.2.3. Assessment of impact

10.2.4. Shadow flicker

10.3. Noise

10.3.1. Terminology and basic concepts

10.3.2. Wind turbine noise

10.3.3. Measurement of wind turbine noise

10.3.4. Prediction and assessment of wind turbine noise

10.3.5. Low frequency noise

10.4. Electromagnetic Interference

10.4.1. Impact of wind turbines on communication systems

10.4.2. Impact of wind turbines on aviation radar

10.5. Ecological assessment

10.5.1. Impact on birds

10.5.2. Impact on bats

References

Software

11. Wind energy and the electric power system

11.1. Introduction

11.1.1. The electric power system

11.1.2. Electrical distribution networks

11.1.3. Electrical generation and transmission systems

11.2. Wind turbine electrical systems

11.2.1. Wind turbine transformers

11.2.2. Protection of wind turbine electrical systems

11.2.3. Lightning protection of a wind turbine

11.3. Wind farm electrical systems

11.3.1. Power collection system

11.3.2. Earthing (grounding) of wind farms

11.4. Connection of wind farms to distribution networks

11.4.1. Power system studies

11.4.2. Electrical protection of a wind farm

11.4.3. Islanding and anti-islanding protection

11.4.4. Utility protection of a wind farm

11.5. Crid Codes and connection of large wind farms to transmission networks

11.5.1. Continuous operation capability

11.5.2. Reactive power capability

11.5.3. Frequency response

11.5.4. Fault ride through

11.5.5. Fast fault current injection

11.5.6. Synthetic inertia

11.6. Wind energy and the generation system

11.6.1. Development (planning) of a generation system including wind energy

11.6.2. Operation of a generation system including wind energy

11.6.3. Wind power forecasting

11.7. Power quality

11.7.1. Voltage flicker perception

11.7.2. Measurement and assessment of power quality characteristics of grid connected wind turbines

11.7.3. Harmonics

11.8. Wind energy and the generation system

11.8.1. Capacity credit

11.8.2. Wind power forecasting

References

Appendix A11 Simple calculations for the connection of wind turbines

A11.1 The Per-unit system

A11.2 Power flows, slow voltage variations and network losses

12. Offshore wind turbines and wind farms

12.1. Offshore wind farms + Appendix 12.1 Costs of Electricity

12.2. The offshore wind resource

12.2.1. Winds offshore

12.2.2. Site wind speed assessment

12.2.3. Wakes in offshore wind farms

12.3. Design loads

12.3.1. International Standards

12.3.2. Wind conditions

12.3.3. Marine conditions

12.3.4. Wave spectra

12.3.5. Ultimate loads: operational load cases and accompanying wave climates

12.3.6. Ultimate loads: non-operational load cases and accompanying wave climates

12.3.7. Fatigue loads

12.3.8. Wave theories

12.3.9. Wave loading on support structure

12.3.10. Constrained waves

12.3.11. Analysis of support structure loads

12.4. Machine size optimisation

12.5. Reliability of offshore wind turbines

12.6. Fixed Support Structures - Overview

12.7. Fixed Support structures

12.7.1. Monopiles – Introduction

12.7.2. Monopiles – Geotechnical design

12.7.3. Monopiles – Steel design

12.7.4. Monopiles - Fatigue analysis in the frequency domain

12.7.5. Gravity bases

12.7.6. Jacket structures

12.7.7. Tripod structures

12.7.8. Tripile structures

12.7.9. S-N curves for fatigue design

12.8. Floating support structures

12.8.1. Introduction

12.8.2. Floater concepts

12.8.3. Design standards

12.8.4. Design considerations

12.8.5. Spar buoy design space

12.8.6. Semi-submersible design space

12.8.7. Station keeping

12.8.8. Spar buoy case study – Hywind Scotland

12.8.9. Three column semi-submersible case study – WindFloat Atlantic

12.8.10. Ring shaped floating platform –Floatgen, France

12.9. Environmental assessment of offshore wind farms

12.9.1. Environmental impact assessment

12.9.2. Contents of the environmental statement of an offshore wind farm

12.9.3. Environmental monitoring of wind farms in operation

12.10. Offshore power collection and transmission systems

12.10.1. Offshore wind farm transmission systems

12.10.2. Submarine AC cable systems

12.10.3. HVDC transmission

References

Index