IEC 61400-1-2019 pdf free download

IEC 61400-1-2019 pdf free download.Wind energy generation systems Part 1 : Design requirements.
6 External conditions
6.1 General
The external conditions described in Clause 6 shall be considered in the design of a wind turbine.
Wind turbines are subjected to environmental and electrical conditions that may affect their loading, durability and operation. To ensure the appropriate level of safety and reliability, environmental, electrical and soil parameters shall be taken into account in the design and shall be explicitly stated in the design documentation.
The environmental conditions are further divided into wind conditions and other environmental conditions. The electrical conditions refer to the electrical power network conditions. Soil properties are relevant to the design of wind turbine foundations.
The external conditions are subdivided into normal and extreme categories. The normal external conditions generally concern recurrent structural loading conditions, while the extreme external conditions represent rare external design conditions. The design load cases shall consist of potentially critical combinations of these external conditions with wind turbine operational modes and other design situations,
Wind conditions are the primary external conditions affecting structural integrity. Other environmental conditions also affect design features such as control system function, durability, corrosion.
The normal and extreme conditions, which are to be considered for design according to wind turbine classes, are prescribed in 6.2 to 6.4.
6.2 Wind turbine classes
The external conditions to be considered for design are dependent on the intended site or site type for a wind turbine installation. Wind turbine classes are defined in terms of wind speed. wind turbine class I, II and Ill, and turbulence parameters, turbulence category A+, A, B, and C. The intention of the classes is to cover most applications. The values of wind speed and turbulence parameters are intended to represent many different sites and do not give a precise representation of any specific site, see 11 .3. The wind turbine classification offers a range of robustness clearly defined in terms of the wind speed and turbulence parameters. In order to allow the use of wind turbine classes for areas, which may experience very high extreme winds in an otherwise moderate wind climate, a T class reference wind speed is included. Such conditions may be found in areas subject to tropical cyclones. IEC 61400-1-2019 pdf free download.