Risk-based Comparative Study of Fluid Power Pitch Concepts

Publikation: Bidrag til bog/antologi/rapport/konference proceedingKonferenceartikel i proceedingForskningpeer review

2 Citationer (Scopus)

Resumé

Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk. Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where a common supply delivers to cylinder drives mounted at each blade, the concept using bootstraps are fully contained in the rotating hub and act as standalone actuators. Clear advantages of such systems are a reduction of high pressure leakage paths, but in turn more components are used for each supply circuit. To allow for comparison, this paper deals with a risk-based analysis of these two types of pitch concepts. The risk-based analysis is conducted according to a qualitative failure analysis method which is verified against recent field failure data for hydraulic pitch systems. The method combines Fault Tree Analysis and Failure Mode and Effect Criticality Analysis in a systematic framework that lowers the bias issues normally encountered for qualitative studies. Under the assumption of similar components, the results indicate an equal risk of the two concepts. A decreased reliability is seen for the bootstrap concept due to additional components in the supply circuit compared to the conventional system. It is noted that careful selection of high reliable pumps and relief valves may significantly reduce risk and increase reliability of the bootstrap concept.
OriginalsprogEngelsk
TitelProceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control
Antal sider9
ForlagAmerican Society of Mechanical Engineers
Publikationsdatookt. 2017
ISBN (Elektronisk)978-0-7918-5833-2
DOI
StatusUdgivet - okt. 2017
BegivenhedASME/BATH 2017 Symposium on Fluid Power & Motion Control - Lido Beach Resport, Sarasota, USA
Varighed: 16 okt. 201719 okt. 2017
http://www.asmeconferences.org/FPMC2017/

Konference

KonferenceASME/BATH 2017 Symposium on Fluid Power & Motion Control
LokationLido Beach Resport
LandUSA
BySarasota
Periode16/10/201719/10/2017
Internetadresse

Fingerprint

Fluids
Hydraulics
Pressure relief valves
Fault tree analysis
Networks (circuits)
Wind turbines
Failure modes
Failure analysis
Turbines
Actuators
Pumps

Citer dette

Liniger, J., Pedersen, H. C., & N. Soltani, M. (2017). Risk-based Comparative Study of Fluid Power Pitch Concepts. I Proceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control American Society of Mechanical Engineers. https://doi.org/10.1115/FPMC2017-4222
Liniger, Jesper ; Pedersen, Henrik Clemmensen ; N. Soltani, Mohsen. / Risk-based Comparative Study of Fluid Power Pitch Concepts. Proceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control. American Society of Mechanical Engineers, 2017.
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abstract = "Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk. Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where a common supply delivers to cylinder drives mounted at each blade, the concept using bootstraps are fully contained in the rotating hub and act as standalone actuators. Clear advantages of such systems are a reduction of high pressure leakage paths, but in turn more components are used for each supply circuit. To allow for comparison, this paper deals with a risk-based analysis of these two types of pitch concepts. The risk-based analysis is conducted according to a qualitative failure analysis method which is verified against recent field failure data for hydraulic pitch systems. The method combines Fault Tree Analysis and Failure Mode and Effect Criticality Analysis in a systematic framework that lowers the bias issues normally encountered for qualitative studies. Under the assumption of similar components, the results indicate an equal risk of the two concepts. A decreased reliability is seen for the bootstrap concept due to additional components in the supply circuit compared to the conventional system. It is noted that careful selection of high reliable pumps and relief valves may significantly reduce risk and increase reliability of the bootstrap concept.",
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Liniger, J, Pedersen, HC & N. Soltani, M 2017, Risk-based Comparative Study of Fluid Power Pitch Concepts. i Proceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control. American Society of Mechanical Engineers, ASME/BATH 2017 Symposium on Fluid Power & Motion Control, Sarasota, USA, 16/10/2017. https://doi.org/10.1115/FPMC2017-4222

Risk-based Comparative Study of Fluid Power Pitch Concepts. / Liniger, Jesper; Pedersen, Henrik Clemmensen; N. Soltani, Mohsen.

Proceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control. American Society of Mechanical Engineers, 2017.

Publikation: Bidrag til bog/antologi/rapport/konference proceedingKonferenceartikel i proceedingForskningpeer review

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N2 - Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk. Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where a common supply delivers to cylinder drives mounted at each blade, the concept using bootstraps are fully contained in the rotating hub and act as standalone actuators. Clear advantages of such systems are a reduction of high pressure leakage paths, but in turn more components are used for each supply circuit. To allow for comparison, this paper deals with a risk-based analysis of these two types of pitch concepts. The risk-based analysis is conducted according to a qualitative failure analysis method which is verified against recent field failure data for hydraulic pitch systems. The method combines Fault Tree Analysis and Failure Mode and Effect Criticality Analysis in a systematic framework that lowers the bias issues normally encountered for qualitative studies. Under the assumption of similar components, the results indicate an equal risk of the two concepts. A decreased reliability is seen for the bootstrap concept due to additional components in the supply circuit compared to the conventional system. It is noted that careful selection of high reliable pumps and relief valves may significantly reduce risk and increase reliability of the bootstrap concept.

AB - Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk. Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where a common supply delivers to cylinder drives mounted at each blade, the concept using bootstraps are fully contained in the rotating hub and act as standalone actuators. Clear advantages of such systems are a reduction of high pressure leakage paths, but in turn more components are used for each supply circuit. To allow for comparison, this paper deals with a risk-based analysis of these two types of pitch concepts. The risk-based analysis is conducted according to a qualitative failure analysis method which is verified against recent field failure data for hydraulic pitch systems. The method combines Fault Tree Analysis and Failure Mode and Effect Criticality Analysis in a systematic framework that lowers the bias issues normally encountered for qualitative studies. Under the assumption of similar components, the results indicate an equal risk of the two concepts. A decreased reliability is seen for the bootstrap concept due to additional components in the supply circuit compared to the conventional system. It is noted that careful selection of high reliable pumps and relief valves may significantly reduce risk and increase reliability of the bootstrap concept.

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Liniger J, Pedersen HC, N. Soltani M. Risk-based Comparative Study of Fluid Power Pitch Concepts. I Proceedings of ASME/BATH 2017 Symposium on Fluid Power & Motion Control. American Society of Mechanical Engineers. 2017 https://doi.org/10.1115/FPMC2017-4222