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Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
International Electrotechnical Commission. IEC 61400: Wind turbine generator systems. IEC, Geneva, including the following Parts: IEC 61400-1 (1999) Part 1: Safety requirements (Edition 2)IEC 61400-2 (1996) Part 2: Safety of small wind turbinesIEC 61400-11 (2002) Part 11: Acoustic noise measurement techniquesIEC 61400-12 (1998) Part 12: Wind turbine power performance testingIEC 61400-13 (2001) Part 13: Measurement of mechanical loadsIEC 61400-21 (2001) Part 21: Measurement and assessment of power quality characteristics of grid connected wind turbinesIEC 61400-23 (2001) Part 23: Full-scale structural testing of rotor bladesIEC 61400-24 (2002) Part 24: Lightning protection
Introduction to loads and structures
Published in Martin O. L. Hansen, Aerodynamics of Wind Turbines, 2015
After having described in detail how to calculate the aerodynamic loads on a wind turbine, the following material concerns structural issues to ensure that the construction will not break down during its typical design lifetime of 20 years. Normally a breakdown is caused by an inadequate control system, extreme wind conditions, fatigue cracks or a defective safety system. A very dangerous breakdown may occur if the power to the generator is lost. There is then no braking torque on the rotor which, in the absence of a safety system such as mechanical or aerodynamic emergency brakes, is free to accelerate. Because the aerodynamic forces increase with the square of the rotor speed, the blades will bend more and more in the downwind direction and might end up hitting the tower or flying off due to centrifugal forces. It has been estimated (Sørensen, 1983) that blades sheared from an over-speeding wind turbine can land up to about 300 metres from the tower. Fortunately, violent failures are extremely rare and no humans have, to the author’s knowledge, ever been reported to have suffered injuries from debris flying off a wind turbine. Safety standards, such as (IEC 61400, 2004), exist to ensure that wind turbines operate safely. The standards define load cases, such as extreme gusts, which a wind turbine must be able to survive. Lightning is also known to have caused disintegration of blades.
Electricity generation
Published in Sven Ruin, Göran Sidén, Small-Scale Renewable Energy Systems, 2019
It is standard practice for large wind turbines to have a type certificate, which means that an accredited third-party certification organization has reviewed the compliance with standards (normally in the IEC 61400 series). Also some small wind turbines can be found that have a type certificate to the international small wind turbine standard IEC 61400-2 or to other schemes like MCS in the UK. In Japan, ClassNK certification is used for small wind turbines. Regarding Danish type approval of small wind turbines, see the website links listed later.
Testing of low-voltage ride through capability compliance of wind turbines – a review
Published in International Journal of Ambient Energy, 2018
Rini Ann Jerin A, Palanisamy Kaliannan, Umashankar Subramaniam
The testing may involve either hardware tool or simulation to study and validate. These tools utilised and challenges associated with them for assessment and testing of grid code compliance are elucidated. The hardware setup and control system provided by the manufacturers for FRT/LVRT capability vary within manufacturers and also remain as non-public information (E.ON Nets 2006; Energinet.dk 2010; Mohseni and Islam 2012). Therefore, it becomes difficult to compare various cases or studies due to restricted distribution of these models. Based on these needs, a publicly available model whose parameters are described is available to predict the performance of Doubly Fed Induction Generator (DFIG) during voltage dips reliably. The International Electrotechnical Commission (IEC) is focused on the development of an international standard, IEC 61400-27, related to the definition of generic (i.e. simplified or standard) dynamic models for wind power systems. These generic models are intended to be applicable to transient and dynamic events, such as faults, loss of generation or loads and switching of lines. These IEC models aim to be applicable to dynamic simulations of power system events, such as short circuits (LVRT), loss of generation or loads and typical switching events. IEEE has defined four generic wind turbine model types that are commercially available for Type 1, Type 2, Type 3 and Type 4 (Honrubia-Escribano et al. 2015).