2009-05-08 S-02872-012 Amendment Final...

ENERCON Service Center – Customer Relations – Dornumer Straße 20 – 26607 Aurich – Phone +49 4941 976 385 Fax +49 4941 976 319 – Email: [email protected]

Amendment Final Report

Pages: 42 Contents:

1. Data of WEC 2. Introduction 3. Assembling of compression flange 4. Measurement of evenness 5. Analysis of torn off studs 6. Allocation of studs in regard to the position of the rotor blade 7. Summary 8. Annex

Annex 1: Montagem da Flange na Pa E-48-1 Annex 2: Results of the evenness measurement Annex 3: Test report 4073-09 Annex 4: Stud position Annex 5: Production reports rotor blade set (portuguese and english version)

1. Data of WEC

Serial no: 481454 / Turbine No. 12 Site address: Fen Farm Wind Park; Fen Lane, Conisholme; Lincs, LN11

7LU Customer: Next Generation Ltd. Type of WEC: E48 Type of control: CS48a Energy yield: 1,823,340kWh Operating Hours: 6,863h

Time of damage: 2009-01-04 / 06:26:07 Status signal: 73:02 / Torque Monitoring : Peak Load

Vibration sensor trip, turbine shutdown automatically and sent SCADA warning message to Service control – Service Crew despatched immedi-ately to site and on arrival found one blade had detached from turbine and had fallen to the ground and one other blade had a damaged tip but still

Damage at WEC with serial no:

481454 / S-02872-012

Editor Hermann Bohlen / Stephan Menzel / Rainer Schwieters Date 08.05.2009 Subject Blade damage

mailto:[email protected]

ENERCON GmbH . Registered Place of Business: Aurich . Commercial Registration No. HRB 411 (Court of Aurich) Managing Directors / CEOs: Mr. Aloys Wobben . Mr. Hans.Dieter Kettwig

Bank Account No.: Oldenburgische Landesbank . Swift Code OLBODEH2 . IBAN DE54 2802 0050 8424 1991 01 . Commerzbank . Swift Code COBADEFF284 . IBAN DE88 2844 0037 0491 4560 02 . Deutsche Bank AG . Swift Code DEUTDEHB284 . IBAN DE41 2847 0091 0060 62002 01 . Sparkasse Bremen . Swift Code SBREDE22 . IBAN DE03 2905 0101 0001 6312 33 . ABN AMRO Bank N.V./Germany . Swift Code ABNADEFF FRA . IBAN DE61 5023 0400 1028 0050 08 . Landes-bank Baden.Würtemberg . Swift Code SOLADEST . IBAN DE97 6005 0101 0002 4834 50 . VAT.Number DE 181 977 360

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2. Introduction This report is used as an amendment to the Final Report of 25.02.2009 in regard to resultant ques-tions to the former report. In addition to that, all supplementary investigations are described. 3. Assembling of compression flange The assembling of the compression flange is described in detail in “Montagem da Flange na Pa E-48-1”. Due to the fact that the rotor blades were produced in Brazil the description is mainly in Portu-guese (Annex 1). The compression flange is a thin and two parts GRP-ring, which is used for straightening of the real rotor blade GRP-ring. Prior to the assembling of the compression flange, the rotor blade is already prepared with the drill-ings for the transversal studs. During the next production step:

• The front surfaces of the rotor blade will be provided with adhesive • The device for assembling of the compression flange will be attached and levelled in regard

to the transversal studs • The two parts GPR-ring will be inserted in the device for assembling or rather adhesive

bonding • Afterwards the adhesive will be tempered

The compression flange has to be inserted carefully and accurately. In the event of failure an un-evenness or offset/step could occur. Up to the time of the Fen Farm incident, the evenness of the compression flange was not inspected after the adhesive bonding and tempering. Before, it was assumed that an even device result also in an even compression flange. Please find in Annex 5 the production reports of the concerned rotor blade set.



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4. Measurement of evenness The evenness measurement of the compression flange showed an offset/step, which was caused during the production procedure of insertion and thus adhesive bonding of the GRP-ring. The off-set/step is clearly placed at the section point of the two part GRP-ring. In each case, right and left side of the section points, on the evenness measurement protocol (An-nex 2) are the relevant positions. The difference between the Z-values results in the offset/step at the section points. On the left side the difference is 0,705mm (-0,488 / +0,217) and on the right side 0,641 (-0,582 / +0,059). A gap within this section increases the load at the studs. That was clearly verified during the meas-urements. These increased loads decrease the durableness appreciable. The variation (wideness, width) of the gap in practice, which depends on the pre-stressing of the studs, decreases the dur-ableness. The durableness of the separate studs depends on the irregularity on an individual basis. Thus, a general statement regarding the durableness is impossible. The highest loads at the studs were observably in the section of stud no. 5 and in the direct opposite. 5. Analysis of torn off studs Four studs of the total value of 32 of the blade connection were exemplary provided to the official Institute for Material Testing Bremen. Two of them were analysed in detail (Annex 3). As a result of the analysis, the studs were in the required quality and the studs no. 1, 28 and 32 demonstrate explicit evidence of fatigue breakage. In addition to that stud no. 16 demonstrates an overload breakage.



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6. Allocation of the stud in regard to the position of the rotor blade In Annex 4 two different reference planes are marked in the drawing. The mould reference plane reflects the partition of the rotor blade during the production procedure. Please note that this mould reference plane is irrelevant for the operation of the turbine. In case the rotor blade is fully driven into the wind and thus to the front side of the rotor hub, the 0°-stud will be driven in the 0°-position of the rotor blade. In Annex 4 the position of the studs are shown, which were analysed by the official Institute for Ma-terial Testing Bremen. 7. Summary The further and above mentioned investigations confirm the result of the Final Report of 25.02.2009. The studs were in the required quality and the studs no. 1, 28 and 32 demonstrate explicit evidence of fatigue breakage. In addition to that stud no. 16 demonstrates an overload breakage. As mentioned in the Final Report of 25.02.2009 we assume that the offset/step at the section point of the compression flange is the cause for the stud breakage. Due to the offset/step the loads were increased and thus decrease the durableness appreciable.



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8. Annex Annex 1:

Montagem da Flange na Pá E48-1

Nº Etapas de Trabalho

1. Comentários Iniciais:

1.1.

Para o acompanhamento do processo e Inspeção do Controle de Qualidade é utilizado o Docu-mento de Fabricação E481– 21 Pá (Montagem1). It´s necessary to use the MR-481-21.

2. Colagem da Flange: Bonding of the flange

2.1. Retirar o nylon interno e externo numa largura de 200mm do Raio 1200 ao Raio 1400. To take away the internal and external peelply from R1200 to R1400.

2.2. Fazer a limpeza do gabarito e aplicar desmoldante (Cera Desmoldante Mold Release TR). To clean the flange gluing device and to apply the demoulding agent.

2.3. Posicionar a flange no gabarito 02GF01 com o lado liso para o gabarito. To put the flange on the device.

2.4. Colocar proteção de espuma nos furos das Barras Roscadas, vide foto abaixo. To put the foam protections on the bar holes.

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Proteção de espuma.

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2.5. Aplicar massa na raiz na área de colagem da flange. To apply the gluing paste.

2.6. Posicionar o gabarito 02GF01 na Pá com auxilio de duas barras guias. To put the device on the root.

2.7. Fixar o gabarito 02GF01 na raiz pelos furos dos Batoques. To fix the gluing device.

2.8. Limpar o excesso de massa interno e externo. To clean the paste excess.

2.9. Colocar a turbina (Processo de cura 1,5h a 60ºC). To turn on the heat turbine.

3. Montagem das Barras Roscadas: Assemblying of the bolts.

3.1.

Retirar o gabarito. To take away the device.

3.2. Limpar o gabarito e aplicar desmoldante no mesmo. To clean the device and to apply the de-moulding agent.

3.3. Repassar broca nos furos das barras roscadas Ф 22 e passar serra copo nos furos dos batoques, com objetivo de eliminar rebarbas. To clean the holes of the bolts and T-bolts with drillers.

Barras guias.

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3.4. Fazer furos de Ф 5.0mm no interior da raiz na direção do furo da barra, no R 1240. Fazer este furo para cada barra roscada. O mesmo serve para injetar pyrmoflex nas barras roscadas. To drill the Ø5mm holes for each bolt in the R1240 to put pyrmopflex.

3.5. Fazer a limpeza do Pó. To clean the powder excess.

3.6 Posicionar o gabarito 02GF01 na raiz e prender com grampos. To put the device on the root and fix it with clamps.

3.7. Aplicar “pasta 20” com pistola pneumática dentro dos furos dos batoques e nos batoques. Espalhar bem a pasta nos furos e nos batoques. To apply paste 2 on the T-bolts and in their holes. Material: Pasta 20 R, un 3082 Pasta 20 H, um 2735

3.8. Posicionar os batoques nos furos alinhando a rosca com a barra roscada. To put the T-bolt in the holes.

R 1200

Furo do Batoque. Furo da Barra Roscada.

Furo com Ф de 5.0mm para aplicação do pyrmoflex.

2



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3.9. Parafusar a barra roscada no batoque com o auxílio de uma parafusadeira pneumática. To screw the bolts.

3. 10.

Colocar arruela, alongador e porca na barra roscada para prender o gabarito na raiz. To put the washers and nuts to fix the bolts.

3. 11. Montar todas as barras. To assembly all the bolts.

3. 12. Colocar turbina (1,5h a 60ºC). To turn on the heat turbine.

3. 13.

Soltar os grampos do gabarito e retirar os pinos dos furos dos batoques. To release the clamps and take away the pins from the T-bolts holes.

3. 14. Montar as barras nas posições dos grampos. To assembly the bolts in the clamps positions.

3. 15. Limpar o excesso de “Pasta 20”. To clean the paste 2 excess.

3. 16.

Apertar todas as barras com o Torquímetro: 150N.m. To screw all the bolts.

3. 17. Colocar a turbina: 1,5h a 60ºC. To turn on the heat turbine.

Parafusadeira pneumática.



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3. 18.

Posição da barra 0º. A primeira barra no Extra Dorso a partir da união das cascas no Bordo de Ataque. The 0° bolt is the first one after the half of the leading edge on clockwise direction.

3. 19.

Após a cura aplicar pyrmoflex pelos furos de 5.0mm com pistola pneumática e limpar os excessos. After curing to apply the pyrmoflex in the Ø5mm holes.

3. 20.

Rebaixar 10mm da Flange da Barra Roscada -2 ao -6. To cut the flange in the pitch motor region.

4. Proteção dos Batoques externos e do Canal de Resina: Protection of the external region of the T-bolts and resin channel.

4.1. Oscilar a região dos Batoques no lado externo, utilizando lixa de grão 40. To sand (oscillating machine) the external region.

4.2. Oscilar a região do canal de Resina. To sand (oscillating machine) the external region.

4.3. Retirar o Pó da região, utilizando Ar comprimido. To clean the powder excess.

4.4. Cortar os tecidos G1, sendo: To cut the specific fabrics. 1 tira de tecido G1 de 150x3.600mm para o reforço dos Batoques. 1 tira de tecido G1 de 150x1.800mm para o reforço do Camal de Resina (para cada Lado).

4.5. Aplicar massa sobre a região oscilada, utilizando uma espatula celuloide. To apply gluing paste.

Extra

Intra

B.A B.F

0º

Oscilante

Canal de Resina.

Oscilante



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4.6. Em uma mesa plana protegida com plástico impregnar com resina líquida os tecidos cortados no item 4.4, utlizando rolinho de lã de carneiro ou similar. To wet the fabrics with resin.

4.7. Aplicar os tecidos impregnado no item anterior em cima da massa aplicada no item 4.5. To apply the fabrics on the external regions.

4.8. Retirar as bolhas, utilizando espatula celuloide. To take the bubbles away.

4.9. Aplicar nylon de 200mm de largura em cima dos tecidos e impregnar com resina líquida, utlizando rolinho de lã de carneiro ou similar. To apply the peelply 200mm width and wet it with resin.

4. 10. Retirar as bolhas, utilizando espatula celuloide. To take the bubbles away from the peelply.

4. 11.

Colocar turbina. To turn on the heat turbine.

Rolinho de lã de carneiro.

Turbina.



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5. Reforços dos Bordos de Ataque e Fuga: Leading and trailing edges reinforcements.

5.1. Retirar o nylon da região dos reforços do R 1.550 ao R 5.500. To take the peelply away from R1550 to R5500. Obs.: se ficar algum pedaço de nylon que não possa ser tirado com a mão, utilizar lixadeira.

5.2. Retirar todo Pó da região, utilizando ar comprimido. To clean the excess of the powder.

5.3. Cortar os tecidos G1G1 para os reforços, sendo: To cut the G1G1 fabrics. Tecidos para o reforço do Bordo de Ataque. Fabrics for LE 1º tecido 200x3.450mm 2º tecido 220x3.700mm 3º tecido 240x3.950mm Tecidos para o reforço do Bordo de Fuga. Fabrics for TE. 1º tecido 200x3.700mm 2º tecido 220x3.950mm 3º tecido 240x4.200mm

5.4. Aplicar massa na região do reforço do R 1.550 ao R 5.500, utilizando uma espatula celuloide. To apply the gluing paste on the reinforcements regions.

5.5. Em uma messa protegida com plástico impregnar com resina líquida os tecidos cortados no item 5.3, utilizando rolinho de lã carneiro ou similar. To wet the fabrics with resin.

Lixadeira

Aplicação de massa com celulóide.



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5.6. Aplicar os tecido do item anterior em cima da massa aplicada no item 5.4, fazer escalonamento conforme esquema ao lado. To apply the fabrics on the reinforcements regions according to the overlaping showed below.

5.7. Retirar as Bolhas, utilizando celulóide. To take the bubbles away.

5.8. Aplicar nylon de 300mm de largura em cima dos tecidos e retirar as bolhas com espatula celulóide. To apply the peelply 300mm width on the fabrics.

5.9. Colocar Turbina. To turn on the heat turbine.

5. 10.

Para o reforço do Bordo de Fuga repetir os mesmos procedimento feitos para o reforço do Bordo de Ataque. Same procedure for both reinformecents LE and TE. Obs.: o reforço d Bordo de Fuga do R 1.550 ao R 5.750. The TE reinforcements from R1550 to R5750.

R 5.500 R 1.550

1º 2º 3º

celulóide

Turbina

R 1.550 R 5.750

1º 2º 3º Aplicação dos tecidos



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Annex 2:



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Annex 3



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