Section 4 Site-specific wind turbine/RNA design evaluation

4.1 Module requirements

4.1.1 The purpose of this evaluation is to confirm that the site-specific WT is in compliance with the design basis. If the WT support structure is of a project-specific design, its evaluation should be included in the design evaluation addressed in Ch 2, 5 Site-specific support structure design evaluation.

4.1.2 This module cannot be completed successfully without prior completion of the design basis evaluation and ILA evaluation (see Ch 2, 2 Design basis evaluation and Ch 2, 3 Integrated loads analysis evaluation).

4.2 Guidance on input requirements

4.2.1 The applicant’s submission for this module’s evaluation should include a comparison between the WT type certification conditions and the actual site conditions as presented in the design basis and IEC 61400-1 Wind turbines – Part 1: Design requirements , IEC 61400-3-1 Wind energy generation systems – Part 3-1: Design requirements for fixed offshore wind turbines or IEC TS 61400-3-2 Wind energy generation systems – Part 3-2: Design requirements for floating offshore wind turbines. The submission should include:

a comparison of the WT type certification load envelope and the site-specific load envelope arising from the ILA covering all wind and turbulent class dependent load cases including waves and currents (unless an ILA is not undertaken because site conditions are less onerous than those assumed for the type-certification); and
an evaluation of any increases in load level or any changes in vibration modes or natural frequencies, including identification of any components that will require reinforcement or modification.

4.2.2 The submission should also include a comparison between the site-specific conditions and those considered in the type certification, including an assessment of any differences (their effect on the WT structural, mechanical, electrical, safety and corrosion protection systems) and a description of the actions taken as a result of the assessment (e.g. design changes to the generator, converter, transformer, switch gear and enclosures). The external conditions to be considered should include:

temperature;
humidity;
solar radiation;
rain, hail, snow and ice;
chemically active substances;
mechanically active particles;
salinity;
electrical conditions; and
lightning.

4.3 Evaluation methodology

4.3.1 LR’s design evaluation will focus on the interfaces between the WT type certification and the preceding modules, including:

consistency of assumptions between the design basis and those made as part of the type certification;
comparison of loads assumed for the WT type certification and the project site-specific loads; and
comparison of the certified design of support structure with the WT and tower design, if applicable.

4.3.2 The design evaluation will include a review of any aspect of the WT design that is not fully covered by the type certification (e.g. modified/new components or systems); this will not result in a reissue of the type certificate by LR as a project certification body.

4.3.3 If during the evaluation any issues arise with regards to the validity of WT design changes, load measurements, functional and component testing with respect to the WT type certificate, these should be brought to the attention of the applicant and request their clarification by the WT certification body.

4.3.4 LR’s design evaluation will include the corrosion protection systems for all WT systems including electrical components, with respect to the site-specific conditions.

4.3.5 For IECRE OD-502 Project Certification Scheme projects, new and/or significantly reinforced WT/RNA components shall be evaluated by an approved RECB under the IECRE OD-501 Type and Component Certification Scheme.