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List of Illustrations
Оглавление1 f10Figure C2 Fixed coordinate system for hub loads and deflections, and positio...
2 Chapter 1Figure 1.1 Wind power capacity worldwide (World Wind Energy Association 2020...Figure 1.2 Wind power capacity by country (US Energy Information Administrat...Figure 1.3 Installed onshore wind power capacity in countries with more than...Figure 1.4 Onshore wind turbines in flat terrain.Figure 1.5 Offshore wind farm.Figure 1.6 Largest commercially available wind turbines.
3 Chapter 2Figure 2.1 Wind spectrum from Brookhaven based on work by Van der Hoven (195...Figure 2.2 Example Weibull distributionsFigure 2.3 The factor Γ(1 + 1/k)Figure 2.4 Turbulence intensities according to various standardsFigure 2.5 Comparison of spectra at 12 m/sFigure 2.6 Comparison of spectra at 25 m/sFigure 2.7 Some asymptotic limitsFigure 2.8 Gust factors calculated from Eq. (2.46)Figure 2.9 Illustration of the Gumbel method
4 Chapter 3Figure 3.1 The energy extracting streamtube of a wind turbine.Figure 3.2 An energy extracting actuator disc and streamtube.Figure 3.3 Variation of C P and C T with axial induction factor a.Figure 3.4 The trajectory of an air particle passing through the rotor disc....Figure 3.5 Tangential velocity grows across the disc thickness.Figure 3.6 Helical vortex wake shed by rotor with three blades each with uni...Figure 3.7 Simplified helical vortex wake ignoring wake expansion.Figure 3.8 The geometry of the vorticity in the cylinder surface.Figure 3.9 The radial and axial variation of axial velocity in the vicinity ...Figure 3.10 The axial variation of tangential velocity in the vicinity of an...Figure 3.11 The axial variation of tangential velocity in the vicinity of an...Figure 3.12 Flow field through an actuator disc for a = 1/3.Figure 3.13 A blade element sweeps out an annular ring.Figure 3.14 Blade element velocities and forces: (a) velocities, and (b) for...Figure 3.15 Power coefficient – tip speed ratio performance curve.Figure 3.16 Comparison of theoretical and measured values of C T .Figure 3.17 Variation of blade geometry parameter with local speed ratio.Figure 3.18 Variation of inflow angle with local speed ratio.Figure 3.19 Optimum blade design for three blades and λ = 6: (a) blade ...Figure 3.20 Uniform taper blade design for optimal operation.Figure 3.21 Spanwise distribution of the lift coefficient required for the l...Figure 3.22 Spanwise distribution of the twist in degrees required for the l...Figure 3.23 Radial variation of the flow induction factors with and without ...Figure 3.24 Spanwise variation of the blade geometry parameter with and with...Figure 3.25 Variation of inflow angle with local speed ratio with and withou...Figure 3.26 The variation of maximum C P with design λ for various lift/...Figure 3.27 Helical trailing tip vortices of a horizontal axis turbine wake....Figure 3.28 Azimuthal variation of a for various radial positions for a thre...Figure 3.29 Spanwise variation of the tip‐loss factor for a blade with unifo...Figure 3.30 Spanwise variation of power extraction in the presence of tip‐lo...Figure 3.31 A (discretised) helicoidal vortex sheet wake for a two bladed ro...Figure 3.32 Prandtl's wake‐disc model to account for tip‐losses.Figure 3.33 Comparison of Prandtl tip‐loss factor with that predicted by a v...Figure 3.34 Spanwise variation of blade circulation for a three blade turbin...Figure 3.35 Spanwise variation of combined tip/root loss factor for a three ...Figure 3.36 Axial flow factor variation with radius for a three blade turbin...Figure 3.37 Variation of blade geometry parameter with local speed ratio, wi...Figure 3.38 Variation of inflow angle with local speed ratio, with and witho...Figure 3.39 Spanwise variation of power extraction in the presence of tip‐lo...Figure 3.40 The variation of maximum C P with designλ for various lift/d...Figure 3.41 The variation of circulation along the length of a blade.Figure 3.42 Pressure measurements on the surface of a wind turbine blade whi...Figure 3.43 A comparison of measured and Snel's predicted power curves for a...Figure 3.44 The aerodynamic characteristics of the NACA632XX aerofoil series...Figure 3.45 Angle of attack distribution for a range of tip speed ratios.Figure 3.46 Distribution of the flow induction factors for a range of tip sp...Figure 3.47 Distribution of blade loads for a range of tip speed ratios (lin...Figure 3.48 Variation of thrust coefficient with tip speed ratio.Figure 3.49 Variation of the actual force with wind speed.Figure 3.50 C P ‐ λ performance curve for a modern three blade tur...Figure 3.51 C P ‐ λ performance curve for a modern three blade tur...Figure 3.52 Effect of changing solidity.Figure 3.53 The effect of solidity on torque.Figure 3.54 The effect of solidity on thrust.Figure 3.55 Non‐dimensional performance curves for constant‐speed operation....Figure 3.56 Effect on extracted power of rotational speed.Figure 3.57 Effect on extracted power of rotational speed at low wind speeds...Figure 3.58 Effect on extracted power of blade pitch set angle.Figure 3.59 Pitching to feather power regulation requires large changes of p...Figure 3.60 Power vs wind speed curve from the binned measurements of a thre...Figure 3.61 Comparison of measured and theoretical performance curves.Figure 3.62 Measured raw results of a three blade wind turbine.Figure 3.63 C P ‐λ curve for a design tip speed ratio of 7 at 7 m/...Figure 3.64 K P ‐1/λ curve for a fixed‐speed, stall‐regulated turb...Figure 3.65 Power vs wind speed.Figure 3.66 Energy capture curve.Figure 3.67 Energy capture curve for numerical integration.Figure 3.68 Power vs wind speed for variable‐speed turbine.Figure 3.69 NREL aerofoil profiles for large blades.Figure 3.70 The Risø‐A series of aerofoil profiles.Figure 3.71 The Risø‐P series of aerofoil profiles.Figure 3.72 The Risø‐B series of aerofoil profiles.Figure 3.73 The Delft University series of aerofoil profiles.Figure 3.74 Flat‐back aerofoil derived from DU‐97‐W‐300.Figure 3.75 VGs on a blade suction surface. (Flow is from right to left.)Figure 3.76 Flaps and similar acting devices: (a) conventional trailing edge...Figure 3.77 Lift coefficient vs jet momentum coefficient for jet circulation...Figure 3.78 Low noise aerofoil family: (a) DTU‐LN1xx, (b) DTU‐LN2xx, and (c)...Figure 3.79 Diagram of serrated trailing edge for reduction of TE noise.Figure A3.1 Flow past a streamlined body.Figure A3.2 Boundary layer showing the velocity profile.Figure A3.3 Separation of a boundary layer.Figure A3.4 Separated flow past a flat plate.Figure A3.5 Laminar and turbulent boundary layers.Figure A3.6 Variation of C d with Re for a long cylinder.Figure A3.7 Flow past a rotating cylinder.Figure A3.8 Circulatory flow round a rotating cylinder.Figure A3.9 Flow past an aerofoil at a small angle of attack: (a) inviscid f...Figure A3.10 The pressure distribution around the NACA0012 aerofoil at α...Figure A3.11 The pressure distribution around the NACA0012 aerofoil at α...Figure A3.12 Stalled flow around an aerofoil.Figure A3.13 C l − α curve for a symmetrical aerofoil.Figure A3.14 Variationof C d with α for the NACA0012 aerofoil.Figure A3.15 Lift/drag ratio variation for the NACA0012 aerofoil.Figure A3.16 Variation of the drag coefficient with Reynolds number at low a...Figure A3.17 Variation of the drag and lift coefficients with Reynolds numbe...Figure A3.18 The profile of the NACA4412 aerofoil.Figure A3.19 Classification of the NACAXXXX aerofoil range.Figure A3.20 The characteristics of the NACA4412 aerofoil for Re = 1.5·10...
5 Chapter 4Figure 4.1 A wind turbine yawed to the wind direction.Figure 4.2 Deflected wake of a yawed turbine and induced velocities.Figure 4.3 Power coefficient variation with yaw angle and axial flow factor....Figure 4.4 Velocities and lift and induced drag forces on an autogyro in fas...Figure 4.5 Velocities normal to the yawed rotor.Figure 4.6 The deflected vortex wake of a yawed rotor showing the shed vorti...Figure 4.7 A yawed rotor wake without wake expansion.Figure 4.8 Plan view of yawed actuator disc and the skewed vortex cylinder w...Figure 4.9 Average induced velocities caused by a yawed actuator disc.Figure 4.10 Maximum power coefficient variation with yaw angle, comparison o...Figure 4.11 Axis system for a yawed rotor.Figure 4.12 Flow expansion function variation with radial position and skew ...Figure 4.13 Azimuthal and radial variation of horizontal (v) and vertical (w Figure 4.14 Flow expansion functions for one, two and three blade rotors by ...Figure 4.15 Approximate flow expansion functions for two and three blade rot...Figure 4.16 Øye's curve fit to Coleman's flow expansion function.Figure 4.17 Flow expansion causes a differential angle of attack.Figure 4.18 The velocity components in the plane of a blade cross‐section.Figure 4.19 Azimuthally averaged induced velocity factors for the Delft turb...Figure 4.20 Component velocities, normalised with wind speed, at 30° of yaw....Figure 4.21 Angle of attack variation at 30° of yaw.Figure 4.22 Measured yaw moments on the Delft turbine.Figure 4.23 Calculated yaw moments on the Delft turbine.Figure 4.24 Measured tilt moments on the Delft turbine.Figure 4.25 Calculated tilt moments on the Delft turbine.Figure 4.26 Radial loading distributions of the first two solutions and thei...Figure 4.27 The form of the loading distribution that yields a yawing moment...Figure 4.28 Yawing moment on the Tjæreborg turbine at 32° yaw and 8.5 m/s.Figure 4.29 Measured and calculated blade root bending moment responses to b...Figure 4.30 Unsteady flow and structural velocities adjacent to a rotor blad...Figure 4.31 Wake development after an impulsive change of angle of attack.Figure 4.32 Lift development after an impulsive change of angle of attack.Figure 4.33 The (a) real and (b) imaginary parts of Theodorsen's function.Figure 4.34 Typical dynamic stall behaviour.Figure 4.35 Growing leading edge vortex and idealised feeding sheet.Figure 4.36 Normal force coefficients for a NACA0012 aerofoil in cyclic pitc...Figure 4.37 Sketch of vortex lattice panels on a blade surface and wake.Figure 4.38 Vorticity downstream of a rotor–blade–tower interaction.Figure 4.39 Volume rendering of computed turbulent wakes of a 4 × 4 array of...
6 Chapter 5Figure 5.1 Variation of turbulence intensity with wind speed for the normal ...Figure 5.2 IEC 61400‐1 extreme rising and falling gust with 50 year return p...Figure 5.3 Simulated wind speed time series constrained to give a 44.5 m/s p...Figure 5.4 (a) Blade SC40 chord and thickness distributions. (b) Blade SC40 ...Figure 5.5 (a) Spanwise variation of resonant and quasi‐static moments – bla...Figure 5.6 Distribution of blade in‐plane and out‐of‐plane aerodynamic loads...Figure 5.7 Distribution of blade in‐plane and out‐of‐plane aerodynamic bendi...Figure 5.8 Blade out‐of‐plane root bending moment during operation in steady...Figure 5.9 Aerofoil data for LM 19.0 blade for various thickness/chord ratio...Figure 5.10 (a) Variation of blade root bending moment with azimuth, for an ...Figure 5.11 (a) Variation of blade root bending moments with azimuth due to ...Figure 5.12 Tower shadow parameters.Figure 5.13 Profiles of velocity deficit due to tower shadow at different di...Figure 5.14 Variation of blade root out‐of‐plane bending moment with azimuth...Figure 5.15 Blade SC40 gravity bending moment distribution.Figure 5.16 Gyroscopic acceleration of a point on a yawing blade.Figure 5.17 (a) Geometry for the derivation of the velocity auto‐correlation...Figure 5.18 Normalised auto‐correlation and cross‐correlation functions for ...Figure 5.19 (a) Rotationally sampled power spectra of longitudinal wind spee...Figure 5.20 Comparison of rotationally sampled power spectra at 40 m radius ...Figure 5.21 Rotationally sampled cross‐spectrum of longitudinal wind speed f...Figure 5.22 Simulated time series of wind speed fluctuations at two points 1...Figure 5.23 Deflection of tip due to flapwise bending of twisted blade (view...Figure 5.24 Restoring moments due to centrifugal force for in‐plane and out‐...Figure 5.25 Blade out‐of‐plane root bending moment dynamic response to tower...Figure 5.26 Blade out‐of‐plane root bending moment dynamic response to tower...Figure 5.27 Campbell diagram for blade SC40.Figure 5.28 Power spectrum of blade SC40 first out‐of‐plane mode tip deflect...Figure 5.29 Teeter geometry.Figure 5.30 Teeter angle power spectrum for two bladed rotor with SC40 blade...Figure 5.31 Fundamental mode shapes of blade and tower.Figure 5.32 Tower top and blade tip deflections resulting from tower shadow,...Figure 5.33 Derivation of blade bending stresses at radius r* due to aerodyn...Figure 5.34 Effect of variation of phase angle between harmonics on combined...Figure 5.35 Low‐speed shaft and front bearing before assembly. The hub mount...Figure 5.36 Shaft bending moments with rotating axis system referred to blad...Figure 5.37 Shaft bending moment fluctuations due to wind shear.Figure 5.38 Components of blade 1 out‐of‐plane root bending moment about fix...Figure 5.39 Rotor thrust during operation in steady, uniform wind: variation...Figure 5.40 Power spectra of rotor thrust and resultant tower base fore–aft ...Figure 5.41 Power spectra of rotor thrust and resultant tower base fore–aft ...Figure 5.42 Blade root bending moment in steady wind.Figure 5.43 Blade root bending moment in turbulent wind for a fixed rotation...Figure 5.44 Spectra of out‐of‐plane loads in turbulent wind.Figure 5.45 Spectra of in‐plane loads in turbulent wind.Figure 5.46 Comparison of techniques for fitting a straight line to empirica...Figure 5.47 Comparison of GEV distributions fitted to empirical data on a Gu...Figure 5.48 Gumbel plot comparison of three extreme value distributions fitt...Figure 5.49 Gumbel plot comparison of four extreme value distributions fitte...Figure 5.50 Local extremes derived from blocks of 12 seconds' duration.Figure 5.51 Probability of j or fewer occurrences of the non‐exceedance of t...Figure A5.1 Power spectrum of wind turbulence and frequency response functio...Figure A5.2 Size reduction factors for the first mode resonant response due ...
7 Chapter 6Figure 6.1 Variation of optimum turbine size with wind shear based on simpli...Figure 6.2 (a) Variation of specific blade mass with diameter for LM blades ...Figure 6.3 Variation of cost of energy with turbine diameter for NREL baseli...Figure 6.4 Variation in cost of energy with rated power for a 70 m diameter,...Figure 6.5 Rated power vs swept area for turbines in production in 2008Figure 6.6 Rated power vs swept area for turbines in or close to production ...Figure 6.7 Variation of coefficient of performance, root bending moment coef...Figure 6.8 Variation of maximum C P and corresponding tip speed ratio with li...Figure 6.9 Comparison of C P – λ curves for three bladed baseline machin...Figure 6.10 Pitch‐teeter couplingFigure 6.11 Comparison of power curves for (i) stall‐regulated, fixed‐speed;...Figure 6.12 Power curves for different positive pitch angles: 70 m diameter ...Figure 6.13 Schedule of pitch angles vs wind speed for limiting the power ou...Figure 6.14 Pitch linkage system used in conjunction with a single hydraulic...Figure 6.15 Blade pitching system using separate hydraulic actuators for eac...Figure 6.16 Blade pitching system using a separate electric motor for each b...Figure 6.17 Passive control of tip blade, using screw on tip shaft and sprin...Figure 6.18 Schedule of pitch angles required to limit 70 m diameter turbine...Figure 6.19 Power curves for different negative pitch angles: 70 m diameter ...Figure 6.20 Locus of operation of a two‐speed wind turbineFigure 6.21 Control objective of a variable‐speed wind turbine (see also Cha...Figure 6.22 Wind turbine architectures. (a) Fixed‐speed induction generator,...Figure 6.23 Evolution of commercially available wind turbine generator syste...Figure 6.24 Mechanical analogues of directly connected generatorsFigure 6.25 Superconducting rotor synchronous generatorFigure 6.26 Radial flux magnetic gearboxFigure 6.27 Principle of a cascaded brushless doubly fed induction generator...Figure 6.28 Parallel connection of direct current wind turbine generatorsFigure 6.29 View of nacelle showing traditional drive shaft arrangementFigure 6.30 Nacelle arrangement for the Nordex N60 turbine.Figure 6.31 Drive train side view. From left to right the components visible...Figure 6.32 Turbine assembly in the air (1): View of nacelle of 1.5 MW NEG M...Figure 6.33 Turbine assembly in the air (2): View of low‐speed shaft and fro...Figure 6.34 Direct drive generator arrangementFigure 6.35 Integrated gearbox on the Zond Z‐750 turbine. (The gearbox is mo...Figure 6.36 Nineteen rotors spaced at 30 m mounted on a space frame structur...Figure 6.37 Nineteen rotors spaced at 30 m mounted on a tubular ‘tree’ struc...
8 Chapter 7Figure 7.1 Blade cross‐sectional outlines at stations along the length of a ...Figure 7.2 Wood‐epoxy blade construction utilising full blade shell. Source:...Figure 7.3 Wood‐epoxy blade construction utilising forward half of blade she...Figure 7.4 Glass fibre blade construction using blade skins in forward porti...Figure 7.5 Glass fibre blade construction with twin I‐beams, each formed of ...Figure 7.6 Glass fibre blade construction with box section spar consisting o...Figure 7.7 Failure strain distribution of individual fibres compared with pl...Figure 7.8 Two stress distributions on a + 45/−45° laminate, which, when com...Figure 7.9 Strain‐life regression lines fitted to results of constant amplit...Figure 7.10 CLD in terms of stress for DD16 MD laminate with 36% fibre volum...Figure 7.11 CLD in terms of strain for QQ1 triaxial laminate with 53% fibre ...Figure 7.12 CLD in terms of strain for Optimat MD2 triaxial laminate with 64...Figure 7.13 Linear CLD in terms of characteristic strainsFigure 7.14 Modified linear CLD in terms of characteristic strains, based on...Figure 7.15 Reduction of residual strength with number of constant amplitude...Figure 7.16 Two‐block high–low R = 0.1 fatigue loading, with half the predic...Figure 7.17 Two‐block low–high R = 0.1 fatigue loading, with half the predic...Figure 7.18 CLD for P2B hybrid laminate with 55% fibre volume fraction and [...Figure 7.19 Variation of blade root out‐of‐plane bending moment with wind sp...Figure 7.20 Variation of blade root flapwise bending moment with wind speed ...Figure 7.21 Effect of rapid wind speed fluctuations on 0 m radius flapwise b...Figure 7.22 Relative contribution to lifetime fatigue damage for different w...Figure 7.23 Time history of flapwise BM at 0 m radius, with breakdown betwee...Figure 7.24 FC40 blade plan‐formFigure 7.25 FC40 blade twist and thickness/chord ratio distributionsFigure 7.26 Cross‐section of blade at 32.5% radiusFigure 7.27 Spar cap thickness profile and combined thickness of inner and o...Figure 7.28 Variation of fatigue stresses at 17 m radius with wind speed for...Figure 7.29 Variation of fatigue damage with wind speed at 17 m radiusFigure 7.30 (a) Velocity diagram for vibrating blade (looking towards hub). ...Figure 7.31 Variation in damping coefficient at 14 m radius with vibration d...Figure 7.32 Typical buckling mode shape of DTU 10 MW reference turbine sucti...Figure 7.33 Typical buckling mode shape of DTU 10 MW reference turbine sucti...Figure 7.34 Curved panel spanning between shear websFigure 7.35 Variation of axial critical buckling stress with panel width for...Figure 7.36 Variation of axial critical buckling stress with curvature for 5...Figure 7.37 (a) Carrot connector, (b) T‐bolt connector, (c) pin‐hole flange,...Figure 7.38 Blade cross‐section (looking towards hub) and plan view on blade...Figure 7.39 In‐plane contraction and shear distortion of section of suction ...Figure 7.40 Variation with fibre inclination of ϒ xy /σ x = , spar cap lo...Figure 7.41 Variation of coupling coefficients at 62.5% and 32.5% radius for...Figure 7.42 Variation of bending moment fluctuations at blade passing freque...Figure 7.43 Proposed use of fore and aft blade sweep in combination with off...Figure 7.44 Typical pitch bearing arrangmentFigure 7.45 (a) Single‐row crossed roller bearings, (b) single‐row ball bear...Figure 7.46 (a) Tri‐cylindrical hub, and (b) spherical hubFigure 7.47 Rotor hub. View of spherical‐shaped rotor hub for the 1.5 MW NEG...Figure 7.48 Load duration curves for 500 kW, two bladed pitch‐regulated and ...Figure 7.49 Simulated power output for two bladed, 40 m dia pitch‐regulated ...Figure 7.50 Low‐speed shaft torque during braking at normal shut‐down. Extra...Figure 7.51 Specimen torque–endurance curves for gear tooth designFigure 7.52 Steady state equivalent circuit of an induction machine with pow...Figure 7.53 Variation of active power with slip for an induction machine sho...Figure 7.54 Circle diagram of 1 MW induction machineFigure 7.55 Soft‐start unit for an induction generator (one phase only shown...Figure 7.56 Steady state equivalent circuit of variable‐slip induction gener...Figure 7.57 Effect of external resistance on the torque slip curve of an ind...Figure 7.58 Voltage source converterFigure 7.59 (a) Sine‐triangular modulation circuit, and (b) PWM output of si...Figure 7.60 Ideal voltage sources representation of a voltage source convert...Figure 7.61 Typical harmonic spectrum of three phase voltage of a PWM invert...Figure 7.62 Steady state equivalent circuit of the DFIG. Vr is the injected ...Figure 7.63 Steady state torque slip curves of a DFIGFigure 7.64 Torque speed curve of a DFIGFigure 7.65 Power flows in a DFIG. (a) Sub‐synchronous operation. (b) Super‐...Figure 7.66 Schematic of a DFIG wind turbine typical control systemFigure 7.67 Power flows in a full power converterFigure 7.68 High‐speed shaft brake disc and calliper (reproduced by permissi...Figure 7.69 Brake disc surface maximum temperature rise for emergency brakin...Figure 7.70 Emergency braking of stall‐regulated 60 m dia turbine from 10% o...Figure 7.71 Typical arrangement of yaw bearing, yaw drive, and yaw brakeFigure 7.72 Variation of dynamic magnification factors with tower natural fr...Figure 7.73 Variation of buckling strength reduction factor, divided by part...Figure 7.74 Variation in tower base wall thickness with diameter required fo...Figure 7.75 EN 1993‐1‐9:2005 fatigue strength curve for detail category 71 (...Figure 7.76 Bolted flange jointFigure 7.77 Flange joint bolt load variation with externally applied load, Z Figure 7.78 (a) Plain slab, (b) slab and pedestal, (c) stub tower embedded i...Figure 7.79 (a) Pile group and cap, (b) solid monopile, and (c) hollow monop...Figure 7.80 Piled foundation for steel lattice towerFigure 7.81 Example of variation of tower natural frequency with foundation ...
9 Chapter 8Figure 8.1 Low‐speed shaft sensing system. Three proximity sensors mounted o...Figure 8.2 Main control loop for a fixed‐speed pitch‐regulated turbineFigure 8.3 Schematic torque‐speed curve for a variable‐speed pitch‐regulated...Figure 8.4 Use of a tower accelerometer to help control tower vibrationFigure 8.5 Effect of a drive train damping filterFigure 8.6 Comparison of pitch and stall controlFigure 8.7 A simple control algorithm for variable‐speed stall regulationFigure 8.8 Operating envelope for a variable‐slip generatorFigure 8.9 Effect of individual pitch control on rotating out‐of‐plane loads...Figure 8.10 Effect of individual pitch control on yaw moment. Top: without i...Figure 8.11 Effect of 1P and 2P individual pitch control on non‐rotating loa...Figure 8.12 Adding higher harmonic individual pitch control loopsFigure 8.13 Possible LiDAR scanning pattern: a five‐lobed cycloidal scan is ...Figure 8.14 Typical linearised turbine modelFigure 8.15 Simplified general model of plant and controllerFigure 8.16 Damping ratio for a complex pole pairFigure 8.17 Example root locus plot for a variable‐speed pitch controllerFigure 8.18 Pitch rate limit modification for a variable‐slip wind turbineFigure 8.19 Structure of the LQG controllerFigure 8.20 Limits applied to a PI controller
10 Chapter 9Figure 9.1 Diagram of the Jensen velocity deficit model.Figure 9.2 Typical Gaussian wake velocity profile from the Ainslie model.Figure 9.3 Wake steering control by yawing (schematic).
11 Chapter 10Figure 10.1 (a) Binned PDF of wind speed. (b) Power curve at each wind speed...Figure 10.2 Scatter plot for MCP.Figure 10.3 Example of an energy map (GWh/year) of a prospective wind farm s...Figure 10.4 Wind farm of six 660 kW turbines in flat terrain.Figure 10.5 Wind farm of 600 kW turbines at Tarifa, Spain.Figure 10.6 Wind farm of 700 kW turbines along a coast.Figure 10.7 Large wind farm on flat upland terrain.Figure 10.8 Example of ZTV (visual impact) of a wind farm. See Plate 4 for c...Figure 10.9 Example of wireframe showing visibility of three wind farms.Figure 10.10 Example of photomontage.Figure 10.11 (a) 3‐D view of a wind farm. (b) 3‐D view within a wind farm. (...Figure 10.12 Example of shadow flicker prediction. The continuous line shows...Figure 10.13 Noise contours around a small wind farm.Figure 10.14 Example of noise criterion proposed by the UKWorking Group on N...Figure 10.15 Example of noise criterion proposed by the UKWorking Group on N...Figure 10.16 Interference mechanisms of wind turbines with radio systems.Figure 10.17 Interference regions of a wind turbine.Figure 10.18 Illustration of first Fresnel zone (Fresnel ellipsoid).Figure 10.19 Example of areas where a wind turbine would mask radar.Figure 10.20 Evaluation of the impact of wind turbines on radar.
12 Chapter 11Figure 11.1 Large electric power system.Figure 11.2 Typical UK distribution transformer and earthing arrangements.Figure 11.3 Voltage control of a distribution circuit.Figure 11.4 Alternative locations of a transformer in a wind turbine.Figure 11.5 Protection circuitry of a wind turbine.Figure 11.6 Transformer and switchgear of 1.5 MW wind turbine.Figure 11.7 Unprotected GRP wind turbine blade damaged by a positive lightni...Figure 11.8 Blade lightning protection for a large wind turbine.Figure 11.9 Electrical power collection system of a wind farm.Figure 11.10 Schematic of a wind farm earthing system.Figure 11.11 Simplified typical protection scheme for a small wind farm conn...Figure 11.12 Typical shape of continuous and short‐time operating regions.Figure 11.13 Reactive power/power characteristics required in Great Britain....Figure 11.14 Reactive power/power characteristics required in two continenta...Figure 11.15 Commonly used reactive power compensators.Figure 11.16 Frequency response.Figure 11.17 Delta control of real power.Figure 11.18 Typical fault ride through characteristic.Figure 11.19 Additional control loops to provide synthetic inertia to a vari...Figure 11.20 Illustration of generation adequacy.Figure 11.21 Generation merit order, showing the effect of increasing wind g...Figure 11.22 Flows of information in a wind power forecasting tool.Figure 11.23 Origin of power quality issues. (a) Disturbances originating in...Figure 11.24 Influence of frequency on the human perception of sinusoidal vo...Figure 11.25 Principle of flicker measurement (IEC 61400‐4‐15 2008b).Figure 11.26 Use of a fictitious grid to establish voltage variations for va...Figure 11.27 Harmonic equivalent circuit of a VSC based wind turbine generat...Figure A11.1 Fixed‐speed wind turbine on a radial circuit.Figure A11.2 Example of calculation of voltage rise on a redial circuit (all...
13 Chapter 12Figure 12.1 Offshore wind farm capacity. (a) Offshore wind farm capacity wor...Figure 12.2 Lillgrund wind farm layout. Lillgrund Pilot Project (2009a).Figure 12.3 Lillgrund wind farm: variation in array efficiency with wind dir...Figure 12.4 Variation of turbulence intensity with wind speed – onshore and ...Figure 12.5 Pierson–Moskowitz (PM) and JONSWAP spectra for H s = 3 m and T p =...Figure 12.6 Simulated water surface elevation time history based on JONSWAP ...Figure 12.7 Data from wind‐wave scatter diagram for site NL‐1.Figure 12.8 Joint probability density of two uncorrelated normally distribut...Figure 12.9 Circle of radius β in U 1 .U 2 space, representing environmental co...Figure 12.10 Fifty year significant wave height against mean wind speed envi...Figure 12.11 Regular wave theory selection diagram: log scales (Barltrop et ...Figure 12.12 Parameter definitions and coordinates for regular, periodic, tw...Figure 12.13 Velocity potential contours for Airy wave theory.Figure 12.14 Horizontal particle velocity at the wave crest: Airy theory as ...Figure 12.15 Streamlines for Airy wave theory with the frame of reference fi...Figure 12.16 Streamlines for Airy wave theory with frame of reference moving...Figure 12.17 Streamlines for Dean stream function wave theory with moving fr...Figure 12.18 Horizontal particle velocity profiles below wave crest and trou...Figure 12.19 Dependence of steady flow drag coefficient on relative roughnes...Figure 12.20 Variation of wake amplification factor, ψ = C D /C DS , with K...Figure 12.21 Variation of inertia coefficient, C M , with Keulegan–Carpenter n...Figure 12.22 Variation of C D , C M , C D /C M , and the ratio of maximum drag force...Figure 12.23 Variation of wave loading on a 4 m dia vertical cylinder over a...Figure 12.24 Variation of wave loading on a 4 m dia vertical cylinder over a...Figure 12.25 Effect of large cylinder diameter on inertia coefficient, based...Figure 12.26 Wave breaking at vertical cylinder.Figure 12.27 Time histories of impulsive force on cylinder according to diff...Figure 12.28 Development of water pile-up as wavefront advances around cylin...Figure 12.29 Time history of force per unit length on cylinder due to breaki...Figure 12.30 JONSWAP spectrum autocorrelation function and its time derivati...Figure 12.31 Simulated water surface time history and desired constraints at...Figure 12.32 Example of a simulated water surface elevation time history con...Figure 12.33 Variation of cost of energy with turbine diameter based on INNW...Figure 12.34 Wind turbine sub‐assembly failure rates and downtime per failur...Figure 12.35 Indicative arrangement of monopile and transition piece with in...Figure 12.36 Response of 0.76 m diameter pile embedded to a depth of 7.6 m i...Figure 12.37 Degradation of clay secant shear modulus with increasing shear ...Figure 12.38 Comparison of measured and predicted ground‐level load‐displace...Figure 12.39 (a) PISA 1‐D pile model showing the soil reaction components ac...Figure 12.40 Form of non‐dimensionalised load‐displacement curves.Figure 12.41 Non‐dimensionalised ultimate lateral load per unit depth versus...Figure 12.42 Large displacement response of an 8.75 m diameter pile embedded...Figure 12.43 Pile rotation versus applied moment during initial loading and ...Figure 12.44 Variation of dimensionless functions T b and T c with M max /M r and...Figure 12.45 Variation of extreme and fatigue moments over height of support...Figure 12.46 Support structure natural frequency exclusion zones for a 5 MW ...Figure 12.47 Variation of support structure weight with mean water depth....Figure 12.48 Example support structure for 5 MW turbine.Figure 12.49 Comparison of quasi‐static and resonant transfer functions for ...Figure 12.50 Effect of diffraction on the transfer function for quasi‐static...Figure 12.51 Variation of aerodynamic damping with wind speed for fixed‐spee...Figure 12.52 Spectra of water surface elevation and resonant mudline bending...Figure 12.53 Mudline moment spectrum approximation.Figure 12.54 Schematic for simplified calculation of fatigue damage.Figure 12.55 Reinforced concrete gravity base design used at Lillgrund wind ...Figure 12.56 Gravity bases for Lillgrund under construction on barge at quay...Figure 12.57 Lowering of gravity base by floating crane during installation ...Figure 12.58 Prestressed concrete gravity base design used at Thornton Bank ...Figure 12.59 Elevation on Blyth gravity base foundation in cross‐section.Figure 12.60 Gravity base foundations for Blyth offshore wind farm under con...Figure 12.61 Four legged jacket structure to support REpower 5 MW turbine at...Figure 12.62 Transition section configured to provide direct load paths from...Figure 12.63 Anchorage of jacket leg to pile using concentric jacket stab‐in...Figure 12.64 Installation of tower, nacelle, and rotor assembly by floating ...Figure 12.65 Theoretical variation of 5 MW turbine monopile support structur...Figure 12.66 Tripile structure after installation. The pile tops, which spor...Figure 12.67 Comparison of design S‐N curves for transverse butt welds witho...Figure 12.68 Double‐sided butt weld with 30° bevel angles.Figure 12.69 Comparison of butt weld fatigue strength reduction factors due ...Figure 12.70 Cumulative failure probability for a weld designed using a DFF ...Figure 12.71 Types of floating offshore wind structures: (a) spar buoy, (b) ...Figure 12.72 Ratios of extreme turbine loads on different floating platforms...Figure 12.73 Spar buoy nomenclature.Figure 12.74 Variation of spar length, steel spar weight, ballast weight, an...Figure 12.75 Possible arrangements of three and four column semi‐submersible...Figure 12.76 Variation of column spacing, draft, notional column steel weigh...Figure 12.77 Variation of column spacing, draft, natural pitching period and...Figure 12.78 Spar buoy mooring system layout.Figure 12.79 Variation of mooring loads, stiffnesses, and inclination with s...Figure 12.80 Artist's impression of Hywind Scotland wind farm.Figure 12.81 Two Hywind spar buoys loaded onto a vessel prior to flotation....Figure 12.82 Pitch motion of all five turbines during operation in a mean wi...Figure 12.83 WindFloat Atlantic platform during load‐out from quayside to se...Figure 12.84 Floatgen in situ.Figure 12.85 Options for transmission from offshore wind farms.Figure 12.86 Typical UK Round 2 offshore wind farm power collection and tran...Figure 12.87 Per‐phase approximate equivalent circuit of 1 km of 132 kV cabl...Figure 12.88 Typical offshore wind farm ac connection.Figure 12.89 Impedance of the network of Figure 12.88 seen from 132 kV busba...Figure 12.90 Voltage propagating through a wind turbine power collection rad...Figure 12.91 VSC HVdc transmission from an offshore wind farm.Figure 12.92 MMC using half bridges.
