BS EN IEC 61400-3-1:2019
$256.21
Wind energy generation systems – Design requirements for fixed offshore wind turbines
| Published By | Publication Date | Number of Pages |
| BSI | 2019 | 154 |
This part of IEC 61400 specifies additional requirements for assessment of the external conditions at an offshore wind turbine site and specifies essential design requirements to ensure the engineering integrity of fixed offshore wind turbines. Its purpose is to provide an appropriate level of protection against damage from all hazards during the planned lifetime. This document focuses on the engineering integrity of the structural components of an offshore wind turbine but is also concerned with subsystems such as control and protection mechanisms, internal electrical systems and mechanical systems. A wind turbine shall be considered as a fixed offshore wind turbine if the support structure is subject to hydrodynamic loading and it is founded on the seabed. The design requirements specified in this document are not sufficient to ensure the engineering integrity of floating offshore wind turbines. For floating installations, reference is made to IEC 61400-3-2. In the remainder of this document, the term “offshore wind turbine” is assumed to refer to those that are fixed to the seabed. This document should be used together with the appropriate IEC and ISO standards mentioned in Clause 2. In particular, this document is fully consistent with the requirements of IEC 61400-1. The safety level of the offshore wind turbine designed according to this document shall be at or exceed the level inherent in IEC 61400-1. In some clauses, where a comprehensive statement of requirements aids clarity, replication of text from IEC 61400-1 is included.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 7 | CONTENTS |
| 12 | FOREWORD |
| 14 | INTRODUCTION |
| 15 | 1 Scope 2 Normative references |
| 16 | 3 Terms and definitions |
| 18 | Figures Figure 1 – Parts of a fixed offshore wind turbine |
| 24 | 4 Symbols and abbreviated terms 4.1 Symbols and units |
| 25 | 4.2 Abbreviations |
| 26 | 5 Principal elements 5.1 General 5.2 Design methods |
| 27 | 5.3 Safety classes 5.4 Quality assurance Figure 2 – Design process for an offshore wind turbine |
| 28 | 5.5 Rotor–nacelle assembly markings 6 External conditions – definition and assessment 6.1 General |
| 29 | 6.2 Wind turbine classes 6.3 Definition of external conditions at an offshore wind turbine site 6.3.1 General |
| 30 | 6.3.2 Wind conditions 6.3.3 Marine conditions |
| 35 | Figure 3 – Definition of water levels |
| 37 | 6.3.4 Electrical power network conditions 6.3.5 Other environmental conditions |
| 38 | 6.4 Assessment of external conditions at an offshore wind turbine site 6.4.1 General 6.4.2 The metocean database |
| 39 | 6.4.3 Assessment of wind conditions Tables Table 1 – Conversion between extreme wind speeds of different averaging periods |
| 41 | 6.4.4 Assessment of marine conditions |
| 45 | 6.4.5 Assessment of other environmental conditions |
| 46 | 6.4.6 Assessment of electrical network conditions 6.4.7 Assessment of soil conditions |
| 47 | 7 Structural design 7.1 General 7.2 Design methodology 7.3 Loads 7.3.1 General 7.3.2 Gravitational and inertial loads |
| 48 | 7.3.3 Aerodynamic loads 7.3.4 Actuation loads 7.3.5 Hydrodynamic loads 7.3.6 Sea/lake ice loads |
| 49 | 7.3.7 Other loads 7.4 Design situations and load cases 7.4.1 General |
| 51 | Table 2 – Design load cases |
| 55 | 7.4.2 Power production (DLC 1.1 to 1.6) |
| 56 | 7.4.3 Power production plus occurrence of fault or loss of electrical network connection (DLC 2.1 – 2.5) |
| 58 | 7.4.4 Start up (DLC 3.1 to 3.3) |
| 59 | 7.4.5 Normal shutdown (DLC 4.1 to 4.2) 7.4.6 Emergency stop (DLC 5.1) |
| 60 | 7.4.7 Parked (standstill or idling) (DLC 6.1 to 6.4) |
| 61 | 7.4.8 Parked plus fault conditions (DLC 7.1 to 7.2) |
| 62 | 7.4.9 Transport, assembly, maintenance and repair (DLC 8.1 to 8.4) |
| 65 | 7.4.10 Sea/lake ice design load cases |
| 66 | 7.5 Load and load effect calculations 7.5.1 General 7.5.2 Relevance of hydrodynamic loads Table 3 – Design load cases for sea/lake ice |
| 67 | 7.5.3 Calculation of hydrodynamic loads 7.5.4 Calculation of sea/lake ice loads 7.5.5 Overall damping assessment for support structure response evaluations |
| 69 | 7.5.6 Simulation requirements |
| 70 | 7.5.7 Other requirements |
| 71 | 7.6 Ultimate limit state analysis 7.6.1 Method |
| 72 | Figure 4 – The two approaches to calculate the design load effect |
| 73 | 7.6.2 Ultimate strength analysis 7.6.3 Fatigue failure |
| 74 | 7.6.4 Special partial safety factors 7.6.5 Assessment of cyclic loading for foundation assessment 8 Control system |
| 75 | 9 Mechanical systems 10 Electrical system 11 Foundation and substructure design |
| 76 | 12 Assembly, installation and erection 12.1 General |
| 77 | 12.2 Planning 12.3 Installation conditions 12.4 Site access |
| 78 | 12.5 Environmental conditions 12.6 Documentation 12.7 Receiving, handling and storage 12.8 Support structure systems 12.9 Assembly of offshore wind turbine |
| 79 | 12.10 Erection of offshore wind turbine 12.11 Fasteners and attachments 12.12 Cranes, hoists and lifting equipment 13 Commissioning, operation and maintenance 13.1 General |
| 80 | 13.2 Design requirements for safe operation, inspection and maintenance |
| 81 | 13.3 Instructions concerning commissioning 13.3.1 General 13.3.2 Energization 13.3.3 Commissioning tests 13.3.4 Records 13.3.5 Post commissioning activities 13.4 Operator’s instruction manual 13.4.1 General |
| 82 | 13.4.2 Instructions for operations and maintenance record 13.4.3 Instructions for unscheduled automatic shutdown 13.4.4 Instructions for diminished reliability 13.4.5 Work procedures plan |
| 83 | 13.4.6 Emergency procedures plan 13.5 Maintenance manual |
| 85 | Annex A (informative)Key design parameters for an offshore wind turbine A.1 Offshore wind turbine identifiers A.1.1 General A.1.2 Rotor-nacelle assembly (machine) parameters A.1.3 Support structure parameters A.1.4 Wind conditions (based on a 10-min reference period and including wind farm wake effects where relevant) |
| 86 | A.1.5 Marine conditions (based on a 3-hour reference period where relevant) A.1.6 Electrical network conditions at turbine |
| 87 | A.2 Other environmental conditions A.3 Limiting conditions for transport, erection and maintenance |
| 88 | Annex B (informative)Shallow water hydrodynamics and breaking waves B.1 Selection of suitable wave theories Figure B.1 – Regular wave theory selection diagram |
| 89 | B.2 Modelling of irregular wave trains B.3 Wave height distributions B.3.1 General B.3.2 The Goda model for maximum wave height |
| 92 | B.3.3 The Battjes and Groenendijk wave height distribution |
| 93 | Table B.1 – Constants h1 and h2 andnormalised wave heights hx % as a function of Htr |
| 95 | B.3.4 The Forristall wave and crest height distributions |
| 97 | B.4 Breaking waves Figure B.2 – Comparison of wave height distribution results |
| 99 | Table B.2 – Breaking wave type |
| 100 | B.5 Reference documents |
| 101 | Annex C (informative)Guidance on calculation of hydrodynamic loads C.1 General |
| 102 | C.2 Morison’s equation |
| 103 | C.3 Diffraction |
| 104 | C.4 Slap and slam loading |
| 105 | Figure C.1 – Breaking wave and cylinder parameters |
| 106 | Figure C.2 – Oblique inflow parameters |
| 107 | C.5 Vortex-induced vibrations C.5.1 General Figure C.3 – Distribution over height of the maximum impact line force (γ = 0°) |
| 108 | C.5.2 Critical velocities for cross-flow motion |
| 109 | C.5.3 Critical velocities for in-line motion Figure C.4 – Response of model and full-scale cylinder in-line and cross-flow |
| 110 | C.6 Appurtenances C.6.1 General C.6.2 Alternative method for estimating hydrodynamic coefficients accounting for appurtenances and marine growth |
| 114 | Figure C.5 – Geometrical definition of blocking and shielding |
| 115 | Figure C.6 – Influence of a fixed boundary on the drag coefficient on a circular cylinder in oscillatory supercritical flow KC > 20, Re = 105 – 2 x 106 |
| 116 | Figure C.7 – Shielding factors |
| 117 | C.7 Calculation methods C.7.1 General Figure C.8 – Recommended value for the added mass coefficient Cmof a circular cylinder; influence of a fixed boundary |
| 118 | C.7.2 Explicit approach C.7.3 Constrained wave approach C.8 Reference documents |
| 120 | Annex D (informative)Recommendations for design of offshore wind turbinesupport structures with respect to ice loads D.1 Introductory remarks D.2 General |
| 121 | D.3 Choice of ice thickness |
| 122 | D.4 Load cases D.4.1 General D.4.2 Horizontal load from fast ice cover originating from temperature fluctuations (DLC D1) |
| 123 | D.4.3 Horizontal load from fast ice cover originating from water level fluctuations and arch effect (DLC D2) D.4.4 Horizontal load from moving ice (DLC D3, D4, D7 and D8) |
| 126 | Figure D.1 – Ice force coefficients for plastic limit analysis |
| 127 | D.4.5 Vertical load from fast ice cover (DLC D5) |
| 128 | D.4.6 Pressure from ice ridges (DLC D6) D.4.7 Dynamic loading (DLC D3, D4, D7, and D8) |
| 130 | Figure D.2 – Ice load history for frequency lock-in conditions Figure D.3 – Time history of horizontal force componentof ice load acting on a conical structure |
| 131 | D.5 Requirements on stochastic simulation D.6 Requirements on model testing |
| 132 | D.7 Reference documents |
| 134 | D.8 Databases for ice conditions |
| 135 | Annex E (informative)Offshore wind turbine foundation and substructure design |
| 136 | Annex F (informative)Statistical extrapolation of operational metocean parameters for ultimate strength analysis F.1 General F.2 Use of IFORM to determine 50-yr significant wave height conditional on mean wind speed |
| 137 | Figure F.1 – Example of the construction of the 50-year environmental contour for a 3-hour sea state duration. |
| 138 | F.3 Examples of joint distributions of V and Hs and approximations to the environmental contour |
| 140 | F.4 Choice of sea state duration F.5 Determination of the extreme individual wave height to be embedded in SSS |
| 141 | F.6 Reference documents |
| 142 | Annex G (informative)Corrosion protection G.1 General G.2 The marine environment |
| 143 | G.3 Corrosion protection considerations G.4 Corrosion protection systems – Support structures |
| 144 | G.5 Corrosion protection in the rotor–nacelle assembly |
| 145 | G.6 Reference documents |
| 146 | Annex H (informative)Prediction of extreme wave heights during tropical cyclones H.1 General H.2 Wind field estimation for tropical cyclones |
| 147 | H.3 Wave estimation for tropical cyclones H.4 Reference documents |
| 148 | H.5 Databases for tropical storms conditions |
| 149 | Annex I (informative)Recommendations for alignment of safety levels in tropical cyclone regions I.1 General I.2 Global robustness level criteria |
| 150 | I.3 Design load cases |
| 151 | Table I.1 – Additional load cases for tropical cyclone affected regions |
| 152 | Bibliography |
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