iec 61400-1:2005 (“edition 3”) -experiences - wind power · pdf filedieser platz...
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IEC 61400-1:2005 (“edition 3”) - Experiences
Germanischer Lloyd Industrial Services Kai Freudenreich, Peter Frohböse
Risö 13.01.2010 No. 2
Contents
• validity and present status of IEC 61400-1:2005
• acceptance / applications / challenges for design assessment
• acceptance / applications for site assessments
• questions raised
• publications by GL
Risö 13.01.2010 No. 3
Validity of IEC 61400-1:2005 - as known to GL
• IEC 61400-1:2005 page 5: „This third edition cancels and replaces the second edition published in 1999. It constitutes a technical revision.“
• IEC secretary statement: „IEC 61400-1:2005 is recommended to be used as soon as published“(instead of IEC 61400-1:1999)
• Certification bodies accept both IEC 61400-1:2005 and IEC 61400-1:1999 - or?
• decision is up to the client – marked survey required
Risö 13.01.2010 No. 4
Validity of IEC 61400-1:2005 - worldwide
• Europe: EN 61400-1:2006 (= IEC 61400-1:2005)
has replaced EN 61400-1:2004, EN 61400-1:2004
is invalid
• Netherlands: IEC 61400-1:2005 has replaced
NVN 11400-0:1999 – but with exceptions
• Denmark: DS/EN 61400-1:2006 has replaced IEC
61400-1:1999 / DS472 – but with exceptions
• India demands IEC 61400-1:2005 or GL Guideline
• IEC 61400-22 demands IEC 61400-1:2005
Risö 13.01.2010 No. 5
Present status of IEC 61400-1:2005
• IEC 61400-1:2005 has been published
in 2005-08
• voting results on the Amendement
IEC 61400-1/A1 (88/339/CDV)
distributed on 27.11.2009
• final IEC 61400-1/A1 to be published
in 2010-02 with minor edititorial
changes
• IEC 61400-1:201x to be started in
spring 2010
Risö 13.01.2010 No. 6
Acceptance of IEC 61400-1:2005 fordesign assessment• clients seem to be interested but also very reluctant
• „looks like a lot of effort“
• „heard that loads will increase“
• intensive discussions necessary on
• validity and accceptance
• application during assessment (mostly on load
extrapolation and contemporaneous loads)
• by far most turbines assessed acc. IEC 61400-1:1999 or
GL Guideline
• IEC 61400-1:2005 presently not well accepted
Risö 13.01.2010 No. 7
Applications of IEC 61400-1:2005 Site specific certification (1)
• Requests for site specific certification acc. to
IEC61400-1:2005 since 2005 are very rare!
• Most request are of discussion type: Do we need to use IEC61400-1:2005 for site specific
certification?
How do we consider XYZ acc to IEC61400-1:2005?
• Site specific certification based on IEC61400-
1:2005 only required if type certification was
performed acc. to IEC61400-1:2005!
Risö 13.01.2010 No. 8
Applications of IEC 61400-1:2005 Site specific certification (2)• Mixing of IEC61400-1:2005 and IEC61400-1:1999 (in
design assessment and site specific calculations must be avoided as basic idea of standard has changed
• Some turbine manufacturers see external pressure that site specific certification needs to be done acc. to IEC61400-1:2005 thus re-certification of the turbine type acc to IEC61400-1:2005 might be needed ���� pressure to shift to new IEC61400-1:2005 comes from the financiers via the projects and not by the turbine buyers / turbine market
Risö 13.01.2010 No. 9
Question / Challenges• general difficulty is how to judge a „good fit“ for load
extrapolation
� final load level may depend on interpretation
wind bin 1 wind bin 2 wind bin 3
Risö 13.01.2010 No. 10
Load level comparison
1.191.151.121.253
1.201.031.191.132
1.151.030.881.091
edge minedge maxflap max
Blade tip
deflection max
Blade root bending momentGL Test
Turbine
Load / deflection from extrapolation + DLC 1.3 with scaled ETM
as fraction of total IEC 61400-1:1999
Risö 13.01.2010 No. 11
Questions – for discussion
• load extrapolation:
• 7.6.2: necessary to run DLC 1.1 until vout ?
Do bins vhub > ~ 16m/s result in overall dimensioning
loads ?
• Annex F.3 Data aggregation first and fitting
afterwards: experience with the weighting of different
bins ?
• Annex F.4 Convergence criteria: experience with
application ?
Risö 13.01.2010 No. 12
Questions – 7.6.2.2 Partial safety factorsfor materials where recognized designcodes are not available
• for non fail-safe components with possibility of rapid
failure of major wind turbine component
• γγγγm ≥ 1.3 for rupture from exceeding tensile or
compression strength
• this approach leads to higher allowable stresses than
for example EN 1563 for cast iron EN-GJS-700-2U:
• Smax = 380 MPa (yield stress) / 1.1 = 345 MPa
(EN 1563)
• Smax = 660 MPa (tensile stress) / 1.3 = 508 MPa
(IEC 61400-1:2005)
Risö 13.01.2010 No. 13
Electromagnetic compatibilty (10.11)
• refers to IEC 61000-6-2 (Immunity
for industrial environments)
• IEC 61000-6-4 (Emission standard
for industrial environment)
• but how to test EMC of a whole turbine?
• or test all components individually?
Risö 13.01.2010 No. 14
Questions - 13 Commissioning, operation and maintenance• Requirements in 13.1 and 13.2 are rather general:
Does IEC intend to apply EN 50308 „Wind turbines
– protective measures – Requirements for design,
operation and maintenance“ ?
Risö 13.01.2010 No. 15
Comments on IEC 61400-1:2005 Site Specific Chapters (1)
• Site Specific Environmental Condition Evaluation and Site Specific LoadCalculation handled in more detail in chapter 11 (before GL Guideline was theonly reference)���� improvement!
• No statement on consistency of standardstype certification and site specificcertification���� customer / user confusion!
Risö 13.01.2010 No. 16
Challenges on IEC61400-1:2005 Site Specific Chapters (2)
• definition of terms have changed: e.g. :characteristic turbulence���� reference turbulence
• wake model now officially Sten Frandsen Model, but new / changed wake calculation method not consistend with the German DIBt and the EN (application of the trust coefficient)
• wake effects should be considered in ultimate loads, but not with the effective turbulence intensity values���� How to consider the influence of wake on extreme loads?
Risö 13.01.2010 No. 17
Open Issues in IEC61400-1:2005 Site Specific Chapters (1)
• terrain complexity definitions are not easy applicable and the definitions are “confusing” to the user���� most important idea: the site is considered complex if the wind conditions indicate parameters to be “complex”
• wind conditions are mostly taken from energy assessment: average wind speed P50 / P90 are at the “wrong end” of the statistical distributions ���� not conservative?! guidance needed!
• ambient turbulence intensity are sometimes calculated based on surface roughness these results deviate from the measured values���� guidance would be helpful!
Risö 13.01.2010 No. 18
Open Issues in IEC61400-1:2005 Site Specific Chapters (2)
• ice load case and definition of icing periods and mass calculation���� what if customer wants to run (power produce) under icing? what is the aerodynamic imbalance / effect of icing?
• effective turbulence: the effect of big wind farms or surrounding wind farms���� should be proved by measurements / tests at the moment this effect seems vague and therewith voluntary in some cases
• assessment of integrity by reference to wind data (chapter 11.9) only refers to basic parameters ���� difficult as there are other environmental parameters influencing the load level and interpretation of the influence on loads is not always easy
Risö 13.01.2010 No. 19
Publications by Germanischer Lloyd
• Best Engineering Practise
• Journal and Conference papers
• Guideline for the Certification of Wind
Turbines by Germanischer Lloyd,
edition 2010
Risö 13.01.2010 No. 20
Best Engineering Practise
• intended to be a GL interpretation for the
application of IEC 61400-1:2005
• additional guidance for data base generation,
extrapolation and DLC 1.3 ETM
• lists alternatives for extrapolation
• simplified check for convergence
• cooking recipe for contemporaneous loads
• lists minimum required documentation
• a living document – changes possible!
Risö 13.01.2010 No. 21
Papers• effect of load extrapolation on extreme loads – comparison
between IEC 61400-1:1999 and IEC 61400-1:2005:
• Freudenreich K, Argyriadis K. “The new standard IEC
61400-1:2005 and its effect on the load level of wind
turbines.” Proceedings of Deutsche Wind Energie
Konferenz, Bremen, 2006.
• Freudenreich K, Argyriadis K. “The Load Level of Modern
Wind Turbines according to IEC 61400-1.” Proceedings of
Special Topics Conference: the Science of Making Torque
from Wind, IOP Publishing Journal of Physics: Conference
Series 75, 2007.
• Freudenreich K, Argyriadis K. “Wind Turbine Load Level
based on Extrapolation and Simplified Methods.” Wind
Energy Vol.11, No.6, pp.589-600, 2008
Risö 13.01.2010 No. 22
GL Guideline - edition 2010 (onshore)
• new edition of „Guideline for the Certification of Wind Turbines“ by Germanischer Lloyd
• planned for spring 2010
• load case catalogue of GL 2003/2004 remains, but withimprovements, e.g.
• non-relevant DLC removed
• split DLC into mandatory and optional (site specific)
• more guidance for icing, active load reduction ...
• loads according to IEC 61400-1:2005 and :1999 also accepted
• new chapter on controller assessment addressing load relevant control and safety system functions
Risö 13.01.2010 No. 24
Any questions ?