AAU logo

PhD defence by Jesper Liniger on Design of Reliable Fluid Power Pitch Systems for Wind Turbines

Time

18.04.2018 kl. 12.30 - 18.04.2018 kl. 16.00

Description

Jesper Liniger, Department of Energy Technology Esbjerg, will defend the thesis "Design of Reliable Fluid Power Pitch Systems for Wind Turbines".

TITLE

Design of Reliable Fluid Power Pitch Systems for Wind Turbines

PHD DEFENDANT

Jesper Liniger

SUPERVISOR

Professor Henrik Clemmensen Pedersen

MODERATOR

Professor Torben O. Andersen  

OPPONENTS

Associate Professor Zhenyu Yang, Department of Energy Technology, Aalborg University Esbjerg (Chairman)
Professor Andrew Plummer, University of Bath, UK
Professor Ronald J. Patton, University of Hull, UK

ABSTRACT

Wind turbines are one of the major contributors of renewable energy and an increase in worldwide capacity is expected. The biggest potential for increasing the capacity, especially in Europe and Asia, is the installation of offshore turbines. Currently, however, the Cost Of Energy (COE) from offshore turbines is double compared with onshore turbines. This means a reduced competitiveness relative to other renewable energy sources. Strategic maintenance aided by condition monitoring and increased reliability is pointed out as key points in reducing the COE for wind turbines.

Through the past decade, several studies on failures in wind turbines have been conducted to reveal reliability and downtime issues in turbine sub-systems. The trend for modern multi-megawatt turbines points to the pitch system being both a major contributor to failure and downtime. Evidently, improving reliability by design and reducing downtime of pitch systems through condition monitoring poses a significant opportunity for lowering the COE produced by modern wind turbines. This research takes its offset in fluid power pitch systems which are preferred on modern offshore turbines by two of the major turbine manufacturers.

Reliability is addressed at the system level by the development of design tool for pitch systems which enables identification of critical failure modes and root causes in terms of both safety and reliability. The design tool builds on qualitative industry methods and presents a validated systematical framework usable even when very limited information is available on component failures. Furthermore, the design tool is utilized for comparing the feasibility of alternative pitch system concepts.

Condition monitoring is addressed for two critical component faults. Namely, the detection of gas leakage of fluid power accumulators and detection of the early signs of coil failure in solenoid valves. Both methods are evaluated experimentally and show promising results in conditions similar to those of wind turbines.

DOWNLOAD AS A PDF

PhD defence by Jesper Liniger on Design of Reliable Fluid Power Pitch Systems for Wind Turbines

ALL ARE WELCOME. THE DEFENCE WILL BE IN ENGLISH and AFTER THE DEFENCE THERE WILL BE AN INFORMAL RECEPTION in the vestibule (C2).

 

 

Host

Department of Energy Technology - Esbjerg

Address

Niels Bohrs Vej 8, room C1.119

Events at AAU

See the list