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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Management System for Operations Mantenanace in Offshore Wind Turbine Plant

Ghanbari, Ahmad, Oyelakin, Muhydeen January 2012 (has links)
Management system for enhancing transfer of knowledge in wind power industry has not received sufficient research attention in recent times. In some cases, the wind power plant owner does not control the management system for operation and maintenance activities. Most of these wind power plants are under contract and rely upon the turbine vendor to perform most of the maintenance works and subsequently share their experience at the initial stage of operation. This research investigates the management system for the operations and maintenance activities of the offshore wind plant in Lillgrund. The research also explores the type of learning method that was adopted by the wind turbine vendor (Siemens) to transfer the operation and maintenance knowledge to the operator and owner (Vattenfall) within the speculated period. It was realized that in the next one year, the Vattenfall would be in full control of the operations and maintenance activities of the offshore wind power plant in Lillgrund. The co-management arrangement will give Siemens a good reputation and gainful experience in the wind power industry. The arrangement is achievable due to Siemens strategy to strive for constructive and long-standing relationships with their customer, based on trust, respect, and honesty. Vattenfall on the other hand, is aiming to be the partner of choice for their suppliers at the same time as best serving their internal customers. The provision for the training during the co-management period enables Siemens to strengthen their relationship with Vattenfall in this industry. In addition, Siemens also maintain close relationship with their customers and develop a large part of their portfolio, frequently on site. Vattenfall improves profitability and value creation, as a fundamental prerequisite for continued growth. The management systems of Vattenfall can be related to professional bureaucracy, this is due to the fact that it was organized to accommodate Siemens experts. Vattenfall benefits from the co-management activities of the operation and maintenance of the Lillgrund wind power plant for a specific period of time. The outcome of the research work has proven that there is an effective time-dependent proportionality for a gradual transfer of the technical knowledge of operation and maintenance from Siemens Wind AB to the Vattenfall personnel. The research started from the perspective of the maintenance method by Swedish standard for wind power, and the way things are being carried out in a more practical way in Lillgrund plant.
2

Analysis of Low Voltage Ride Through Capability of Different Off-shore Wind Farm Collection Schemes

Chen, Yu-Jie 15 July 2012 (has links)
Demand is emerging for offshore wind power plant (WPP) that often has favorable capacity factor and high capacity value as compared with onshore wind farms. There are many challenges regarding power losses, economics, protection system and reliability of the wind farm. Collection system design decisions play an essential role to efficient operation of the WPP. Wind generators also have to be able to cope with grid disturbances. Low voltage ride-through (LVRT) capability of wind turbines requires generator units remain in operation for severe voltage drops during ¡@grid system faults, and be able to withstand depressed voltage for a few seconds in a recovery period. Technical requirements set out in grid codes for off shore wind farm normally relate to different connection points. A rigor LVRT requirement would increase the overall investment costs of the wind farm. In most offshore wind farm projects, radial collector systems connecting a number of wind turbines and terminated at the offshore platform have served well the requirements for an economical design. However, due to the lack of redundancy, its reliability is poor. To improve the reliability of the collector system, the inclusion of a cable section that interconnects the remote ends of two adjacent radial feeders has been proposed. The transmission system of a wind farm takes the power generated and sends it to shore. Medium voltage AC transmission is the simplest one, just gathering the cables from the collector system and taking them together until they reach the point of common coupling (PCC).Through wind farm dynamic simulations by using DIgSIENT package, this thesis demonstrates that the ride through capability which occur at the particular wind parks with different collector system topology are greater than those which the wind turbines are capable of riding through, i.e., LVRT curves of different wind farm collection system designs of an offshore WPP and a single wind generator are different. This can be exploited to reduce the cost in complying with LVRT requirement of offshore WPP.

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