Wind Power Plants Robert Gasch • Jochen Twele Editors Wind Power Plants Fundamentals, Design, Construction and Operation Second Edition Editors Prof. Robert Gasch Prof. Jochen Twele TU Berlin HTW Berlin Fak. V Verkehrs- und Wilhelminenhofstr.
75A Maschinensysteme 12459 Berlin Institut für Luft- und Raumfahrt Germany Marchstr. 12-14 10587 Berlin Germany robert.de ISBN 978-3-642-22937-4 e-ISBN 978-3-642-22938-1 DOI 10.1007/978-3-642-22938-1 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2011937488 ¤ Springer-Verlag Berlin Heidelberg 2012 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcast- ing, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this pub- lication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer.
Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant pro- tective laws and regulations and therefore free for general use. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.com) Preface In 1991, when we sent our manuscript of the first German edition „Wind Power Plants“ to the publishing house, our lecturer Dr.
Schlemmbach was asked by his colleagues “Do you think, anyone will buy and read this book ?” It lasted only one year, until we had to prepare the second edition. The reason for this unexpected success was the first “feed in act” that had passed the German parliament in 1991. Everybody was now allowed to produce electri- city from renewable energies and to feed it into the grid for a fixed price guaran- teed over twenty years. This political decision initiated the boom of the German wind energy industry - similar to the Danish political decision ten years before.
In 1991 most of the authors were members of a research group at the Technical University of Berlin, students, research fellows, postgraduate students and post- docs. Now many of them hold prominent positions in the wind energy industry. This has let to a tightly knit professional network, that helps to keep the book up-to-date. The first English edition (Solar-Praxis, Berlin and James &James, London 2002), based on the 3rd German edition from 1996, was translated by Dörte Müller and Thomas Ackermann, living in Stockholm.
Richard Holmes, Berlin, translated Max Frisch`s Questionnaire. This new English edition is based on the completely revised and extended 5th German edition, Teubner, 2006. It was translated by Christoph Heilmann and reviewed by Wilson Rickerson and Karl E. Stoffers, both from the United States, Jeremy Dunn (Great Britain), Moran Seamus (Ireland) and Simon Cowper (Great Britain).
Heike Müller organized with her skilful hands the graphical work and the final layout. Robert Gasch, Jochen Twele and Christoph Heilmann, Berlin, kept in touch with the co-authors to coordinate the work. We sincerely would like to thank all the contributors for their efforts. We also would like to say thank you to the sponsors and to Dr.
Merkle and Dr. Baumann from the Springer Publishing House for their patience. The editors Berlin, September 2011 Chapters and Authors Chapter 0 Questionnaire 87 Max Frisch Chapter 1 Introduction Prof. Ohde Chapter 2 Historical develop- Prof.
Gasch, ment of windmills Dipl. Schubert Chapter 3 Design and components Prof. Schubert Chapter 4 The wind Dipl. Bade Chapter 5 Blade geometry Prof.
Heilmann Chapter 6 Calculation of perfor- Dr. Maurer, mance characteristics Dr. Heilmann Chapter 7 Scaling wind turbines Prof. Gasch and rules of similarity Chapter 8 Structural dynamics Prof.
Sundermann Chapter 9 Guidelines and Prof. Reuter analysis procedures Chapter 10 Wind pump systems Dr. Kortenkamp Chapter 11 Electricity generation Dipl. Gasch VIII Chapters and Authors Chapter 12 Supervisory and Dipl.
Conrad, control systems Prof. Stoffel Chapter 13 Concepts of electricity Dipl. Conrad, generation Prof. Gasch Chapter 14 Operation at the inter- Prof.
Twele connected grid Dr. Heilmann Chapter 15 Planning, operation and Prof. Twele, economics Dipl. Liersch Chapter 16 Offshore Windfarms Prof.
Kühn Content 0 Questionnaire 87 from Max Frisch 1 Introduction to Wind Energy.1 Wind Energy in the year 2010.2 The Demand for Electricity .3 Energy Policy and Governmental Instruments. 11 2 Historical development of windmills .1 Windmills with a vertical axis .2 Horizontal axis windmills.1 From the post windmill to the Western mill .3 Begin and end of the wind power era in the Occident .4 The period after the First World War until the end of the 1960s.5 The Renaissance of the wind energy after 1980 .3 The physics of the use of wind energy .2 Drag driven rotors .3 Lift driven rotors .4 Comparison of rotors using drag principle and lift principle. 42 3 Wind turbines - design and components .3 Blade pitch system .3 Couplings and brakes .3 Auxiliary aggregates and other components .2 Heating and cooling .4 Tower and foundation.5 Assembly and Production .6 Characteristic wind turbine data .1 Origins of the wind .1 Global wind systems .3 Local wind systems .2 Atmospheric boundary layer .1 Surface boundary layer .2 Vertical wind profile .4 Representation of measured wind speeds in the time domain by frequency distribution and distribution functions .5 Spectral representation of the wind.3 Determination of power, yield and loads .1 Yield calculation using wind speed histogram and turbine power curve.2 Yield calculation from distribution function and turbine power curve.3 Power curve measurement .4 Yield prediction of a wind farm.5 Effects of wind and site on the wind turbine loading .4 Wind measurement and evaluation.5 Prediction of the wind regime .1 Wind Atlas Analysis and Application Programme .2 Meso-Scale models .3 Measure-Correlate-Predict-Methode. 164 5 Blade geometry according to Betz and Schmitz .1 How much power can be extracted from the wind? .1 Froude-Rankine Theorem .2 The airfoil theory .3 Flow conditions and aerodynamic forces at the rotating blade .1 Triangles of velocities .2 Aerodynamic forces at the rotating blade .4 The Betz optimum blade dimensions .3 Losses due to wake rotation .6 The Schmitz dimensioning taking into account the rotational wake.1 Losses due to wake rotation .7 Wind turbine design in practice.
203 6 Calculation of performance characteristics and partial load behaviour .1 Method of calculation (blade element momentum method) .2 Dimensionless presentation of the characteristic curves .3 Dimensionless characteristic curves of a turbine with a high tip speed ratio.4 Dimensionless characteristic curves of a turbine with a low tip speed ratio.5 Turbine performance characteristics .1 Turbines with high and low tip speed ratio: a summary.2 Flow conditions in a turbine with a low design tip speed ratio .3 Flow conditions in a turbine with a high design tip speed ratio .7 Behaviour of turbines with high tip speed ratio and blade pitching.8 Extending the calculation method .1 Start-up range of O < OD (high lift coefficients) .2 Idling range of O> OD (Glauert’s empirical formula) .3 The profile drag.4 The extended iteration algorithm .9 Limits of the blade element theory and three-dimensional calculation methods.1 Lift distribution and three-dimensional effects.2 Dynamic flow separation (Dynamic stall) .3 Method of singularities .4 Computational fluid dynamics applied to wind turbines .5 Examples of CFD application to wind turbines. 248 7 Scaling wind turbines and rules of similarity .1 Application and limits of the theory of similarity .2 Bending stress in the blade root from aerodynamic forces .3 Tensile stress in the blade root resulting from centrifugal forces .4 Bending stresses in the blade root due to weight .5 Change in the natural frequencies of the blade and in the frequency ratios.7 Limitations of up-scaling - how large can wind turbines be? .1 Mass, inertia and gravitational forces .2 Aerodynamic and hydrodynamic loads.3 Transient excitations by manoeuvres and malfunctions .2 Free and forced vibrations of wind turbines - examples and phenomenology .1 Dynamics of the tower-nacelle system .3 Drive train vibrations .4 Sub-models - overall system .5 Instabilities and further aeroelastic problems .3 Simulation of the overall system dynamics.1 Modelling in simulation programs.2 Application of simulation programs .4 Validation by measurement. 304 9 Guidelines and analysis procedures.1 Standard for certification: IEC 61400.2 Guidelines for the Certification of Wind Turbines by Germanischer Lloyd.3 Guidelines for Design of Wind Turbines by DNV .4 Regulation for Wind Energy Conversion Systems, Actions and Verification of Structural Integrity for Tower and Foundation by DIBt.5 Further standards and guidelines.6 Wind classes and site categories .7 Load case definitions.1 Ultimate limit state and the concept of partial safety factors.3 Basics of fatigue analysis .3 Example: Tubular steel tower analysis - mono-axial stress state and isotropic material .1 Ultimate limit state analysis, analysis of extreme loads .2 Fatigue strength analysis .3 Serviceability analysis, natural frequencies analysis .4 Example: Rotor hub analysis - multi-axial stress state and isotropic material .2 Ultimate limit state analysis - critical section plane method .3 Fatigue strength analysis - procedure-dependent S/N curves .5 Example: Rotor blades analysis - mono-axial stress state and orthotropic material .1 Concept of admissible strain for analysis of the chords .2 Local component failure .3 Choice of materials and production methods. 327 10 Wind pump systems .2 Types of wind-driven pumps.3 Operation behaviour of wind pumps .1 Suitable combinations of wind turbines and pumps .2 Qualitative comparison of wind pump systems with piston pump and centrifugal pump.4 Design of wind pump systems.2 Selection of the rated wind speed for the wind pump design .3 Design of a wind pump system with a piston pump .4 Design of a wind pump system with a centrifugal pump.
359 11 Wind turbines for electricity generation - basics .1 The alternator - single-phase AC machine .1 The alternator (dynamo) in stand-alone operation.2 Types of excitation, internal and external pole machine .3 Alternator (single-phase AC machine) in grid-connected operation.2 Three-phase machines .1 The three-phase synchronous machine .2 The three-phase induction machine .3 Power electronic components of wind turbines - converters. 394 12 Supervisory and control systems for wind turbines.1 Methods to manipulate the drive drain .1 Aerodynamic manipulation measures.2 Drive train manipulation using the load.2 Sensors and actuators.3 Controller and control systems .4 Control strategy of a variable-speed wind turbine with a blade pitching system .5 Remarks on controller design. 416 XIV Content Annex I. 424 13 Concepts of electricity generation by wind turbines.1 Grid-connected wind turbines .1 The Danish concept: Directly grid-connected asynchronous generators .2 Directly grid-connected asynchronous generator with dynamic slip control.3 Variable-speed wind turbine with converter and direct voltage intermediate circuit.4 Variable-speed wind turbine with doubly-feeding asynchronous generator and converter in the rotor circuit .5 Power curves and power coefficients of three wind turbine concepts– a small comparison .2 Wind turbines for stand-alone operation .2 Resistive heaters with synchronous generators.3 Wind pump system with electrical power transmission .4 Stand-alone wind turbines for insular grids .5 Asynchronous generator operating in an insular grid .3 Wind turbines in isolated grids.1 Wind-diesel system with a flywheel storage .2 Wind-diesel system with a common DC line .3 Wind-diesel-photovoltaic system (minimal grid).
459 14 Wind turbine operation at the interconnected grid .1 The interconnected electrical grid .1 Structure of the interconnected electrical grid .2 Operation of the interconnected grid .2 Wind turbines in the interconnected electrical grid.1 Technical requirements of the grid connection.2 Interaction between grid and wind turbine operation - network interaction and grid compatibility .3 Characteristics of wind turbine concepts for grid-connected operation. 476 15 Planning, operation and economics of wind farm projects .1 Wind farm project planning.1 Technical planning aspects .2 Legal aspects of the approval process.3 Estimation of economic efficiency .2 Erection and operation of wind turbines .1 Technical aspects of erection and operation of wind turbines.3 Economic efficiency of operation .4 Influence of the hub height and wind turbine concept on the yield .5 General estimation of the annual energy yield of an idealised wind turbine .