IEC 61400 is an International Standard published by the International Electrotechnical Commission
regarding wind turbines.
== Purpose and function == The 61400 is a set of design requirements
made to ensure that wind turbines are appropriately engineered against damage from hazards within
the planned lifetime.
The standard concerns most aspects of the turbine life from site conditions before construction,
to turbine components being tested, assembled and operated.
Wind turbines are capital intensive, and are usually purchased before they are being erected
and commissioned.
Some of these standards provide technical conditions verifiable by an independent, third
party, and as such are necessary in order to make business agreements so wind turbines
can be financed and erected.IEC started standardizing international certification on the subject
in 1995, and the first standard appeared in 2001.The common set of standards sometimes
replace the various national standards, forming a basis for global certification.Small wind
turbines are defined as being of up to 200 m2 swept area and a somewhat simplified IEC
61400-2 standard addresses these.
It is also possible to use the IEC 61400-1 standard for turbines of less than 200 m2
swept area.
The standards for loads and noise are used in the development of prototypes at the Østerild
Wind Turbine Test Field.
== Harmonization ==
In the U.S., standards are intended to be compatible with IEC standards, and some parts
of 61400 are required documentation.The U.S. National Renewable Energy Laboratory participates
in IEC standards development work, and tests equipment according to these standards.
For U.S. offshore turbines however, more standards are needed, and the most important are :
ISO 19900, General requirements for offshore structures
ISO 19902, Fixed steel offshore structures ISO 19903, Fixed concrete offshore structures
ISO 19904-1, Floating offshore structures – mono-hulls, semisubmersibles and spars
ISO 19904-2, Floating offshore structures - tension-leg platforms
API RP 2A-WSD, Recommended practice for planning, designing and constructing fixed offshore
steel platforms - working stress design.In Canada, the previous national standards were
outdated and impeded the wind industry, and they were updated and harmonized with 61400
by the Canadian Standards Association with several modifications.An update for IEC 61400
is scheduled for 2016.For small wind turbines the global industry has been working towards
harmonisation of certification requirements with a "test once, certify everywhere" objective.
Considerable co-operation has been taking place between UK, USA, and more recently Japan,
Denmark and other countries so that the IEC 61400-2 standard as interpreted within e.g.
the MCS certification scheme (of UK origin) is interoperable with the USA (for example
where it corresponds to an AWEA small wind turbine standard) and other countries.
== Wind Turbine Generator (WTG) classes == Wind turbines are designed for specific conditions.
During the construction and design phase assumptions are made about the wind climate that the wind
turbines will be exposed to.
Turbine wind class is just one of the factors needing consideration during the complex process
of planning a wind power plant.
Wind classes determine which turbine is suitable for the normal wind conditions of a particular
site.
Turbine classes are determined by three parameters - the average wind speed, extreme 50-year
gust, and turbulence.Turbulence intensity quantifies how much the wind varies typically
within 10 minutes.
Because the fatigue loads of a number of major components in a wind turbine are mainly caused
by turbulence, the knowledge of how turbulent a site is of crucial importance.
Normally the wind speed increases with increasing height.
In flat terrain the wind speed increases logarithmically with height.
In complex terrain the wind profile is not a simple increase and additionally a separation
of the flow might occur, leading to heavily increased turbulence.
The extreme wind speeds are based on the 3 second average wind speed.
Turbulence is measured at 15 m/s wind speed.
This is the definition in IEC 61400-1 edition 2.
For U.S. waters however, several hurricanes have already exceeded wind class Ia with speeds
above the 70 m/s (156 mph), and efforts are being made to provide suitable standards.
== List of IEC 61400 parts == IEC 61400-1:2005+AMD1:2010 Design requirements
IEC 61400-2:2013 Small wind turbines IEC 61400-3:2009 Design requirements for offshore
wind turbines IEC 61400-4:2012 Design requirements for wind
turbine gearboxes IEC 61400-11:2012 Acoustic noise measurement
techniques IEC 61400-12-1:2005 Power performance measurements
of electricity producing wind turbines IEC 61400-12-2:2013/COR1:2016 Power performance
of electricity-producing wind turbines based on nacelle anemometry / Corrigendum 1
IEC 61400-12-1:2017 lidar measurements IEC 61400-13:2015 Measurement of mechanical
loads IEC TS 61400-14:2005 Declaration of apparent
sound power level and tonality values IEC 61400-21:2008 Measurement and assessment
of power quality characteristics of grid connected wind turbines
IEC 61400-22:2010 Conformity testing and certification IEC 61400-23:2014 Full-scale structural testing
of rotor blades IEC 61400-24:2010 Lightning protection
IEC 61400-25-1:2006 Communications for monitoring and control of wind power plants - Overall
description of principles and models IEC 61400-25-2:2015 Communications for monitoring
and control of wind power plants - Information models
IEC 61400-25-3:2015 Communications for monitoring and control of wind power plants - Information
exchange models IEC 61400-25-4:2008 Communications for monitoring
and control of wind power plants - Mapping to communication profile
IEC 61400-25-5:2006 Communications for monitoring and control of wind power plants - Conformance
testing IEC 61400-25-6:2010 Communications for monitoring
and control of wind power plants - Logical node classes and data classes for condition
monitoring IEC TS 61400-26-1:2011 Time-based availability
for wind turbine generating systems IEC TS 61400-26-2:2014 Production-based availability
for wind turbines IEC 61400-27-1:2015 Electrical simulation
models - Wind turbines
== References ==
== See also ==
IEC 61400-25
== External links == "IEC 61400" at International Electrotechnical
Commission IEC 61400 Wind turbines - All parts