DNV DNV-ST-0437 PDF

Scope and application

This standard is applicable for the determination of design loads for onshore and bottom mounted offshore wind turbines, the relevant site conditions are also within the scope of this standard. For floating offshore wind turbines see DNV-OS-J103. Unless stated otherwise, within this standard the term wind turbine refers to the rotor-nacelle assembly including the support structure of both onshore and offshore wind turbines. Any reference to offshore requirements is meant for offshore wind turbines only.

The standard should be applied in combination with other DNV standards. DNV recommended practices may be utilised to cover specific requirements as outlined in this standard. Where no DNV standards and recommended practices exist, relevant international standards should be utilised.

All applicable requirements specified in this standard shall be fulfilled. Deviations from these requirements, or the application of alternative means to comply with these requirements, may be acceptable, provided that an equivalent level of safety and reliability can be demonstrated. For onshore wind turbines the level of safety resulting from applying IEC 61400-1 in its latest edition will result in an equivalent level of safety. As a consequence, for onshore wind turbines either this standard or IEC 61400-1 may be applied. The mixing of requirements of this standard with requirements of other standards is generally not permitted unless it can be demonstrated that an equivalent or higher level of safety and reliability is reached by doing so.

This standard may be applied as part of the technical basis for carrying out type or component certification of wind turbines according to DNV-SE-0441 as well as for carrying out a project certification of wind power plants according to DNV-SE-0190. It is also intended for application in connection with IEC 61400-22 related certification schemes as described in DNV-SE-0073 and DNV-SE-0074.

The standard is applicable to all types of wind turbines, however, it is most comprehensive for two or three bladed and grid connected horizontal axis wind turbines with active pitch and yaw systems. When this standard is applied for other turbine types, the standard shall be applied logically rather than literally with the target of reaching the same level of safety.

This standard contains the:

— definition and theory regarding external conditions

— determination of site specific design conditions

— calculation and evaluation of loads

— model validation by measurement of loads and power curve.