Environmental Engineering Reference
In-Depth Information
Turbine Type Certification Process
There are few legal requirements for structural design in land-based U.S.
wind energy installations, and no single agency has full responsibility. The
structures must meet local and state building codes, and the electrical sys-
tems must meet electrical standards. These codes and standards are inad-
equate for defining wind turbine design requirements, and there is no
overarching permitting process that addresses structural design. How-
ever, this approach does not appear to have impeded the industry or
become a detriment to public safety. Instead of relying on statutory
regulations, the process is commercially driven. Owners and operators
choose to require type-certified wind turbines for their projects. The type
certification process is outlined in Figure 3-1.
The turbines are usually certified to IEC or other European standards.
Recognizing that the offshore certification process is unique, TC 88 has
begun to draft a second edition of its wind turbine certification process,
IEC 61400-22 (IEC 2010b). The new edition will rely on IEC 61400-3 for
offshore technical requirements while defining the certification process.
Both IEC 61400-3 and WT 01 Ed. 2 assume that the turbine will be certi-
fied to a set of design classes specified in IEC 61400-1 Ed. 3, whereas the
support structure is designed to site-specific conditions. The IEC standards
development process assumes that multiple parties will be responsible for
different aspects of the project and offers guidance for each phase of the
project. It allows for the use of other standards for the support struc-
ture, such as API RP 2A-LRFD-S1 (API 1997), DNV guidelines, and GL
(Optional)
Foundation
Design Evaluation
(Optional)
Characteristic
Measurement
Design
Evaluation
Type Testing
Manufacturing
Evaluation
Final Evaluation
Report
Type Certificate
FIGURE 3-1 Type certification process under IEC 61400-22.
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